VERSION 4.

Parametrics
USER GUIDE

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TABLE OF CONTENTS

Preface 7

Introduction 9
What Is Parametric Design? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
How Parametric Design Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Tooltray . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Dimensioning 25
Dimensions in Parametric Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
Tolerance Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Linear Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Circle and Arc Dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Over-dimensioning and Under-dimensioning. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
Change Dimension Text. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Getting Started 39
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
Creating a Viewbox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Creating a Reference Point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Dimensioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Building the Parametric Grid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Examining the Parametric Grid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Entering Your Own Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Parameterizing an Object. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Example 1: Using a Prim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Example 2: Using Baselines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57

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Simple Parameterization Examples 63

Example One . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Example Two . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Example Three . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Geometric Constraints 75
What Are Geometric Constraints? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
Looking at Inferred Constraints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
Baselines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
Specifying Constraints Explicitly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Example One . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
Example Two . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Example Three . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
Variables and Expressions 91
Values in Dimensions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94
Assigning Values to Variables Using in-sheet commands . . . . . . . . . . . . . . . . . . . . . . . . . . 96
Assigning Values to LCIS Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
Administration, Loading and Updating Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
Errors While Using Variables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104
Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
Layers and Parametric Switches 107
How Layers Are Used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108
Changing Layer Properties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
Parametric Graphics Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
Parametric Switches and Command Texts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
Tables 117
Structure of a Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
Creating a Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
Where to Place a Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
Accessing Values From a Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
Worked Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126
Parameterize Variant from a Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131

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Symbols 133
Creating Parametric Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
Loading Parametric Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
Worked Example 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
Loading Parametric Symbols With Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144
Loading Symbols Using CPI Named Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
Worked Example 2 - CPI Named Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
Parametric Groups 159
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
Creating a Parametric Group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
Example 1: Static Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
Example 2: Dynamic Group with One Prim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
Example 3: Dynamic Group with Two Prims . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167
Example 4: Rotating Parametric Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
Example 5: Dynamic Group with Three Prims . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172
Post-Parameterization 175
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176
Dialog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
Creating Post-Parametric Definition Sheets. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 180
Callbacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
Demo Sheet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
Simulating Mechanisms 189
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
Dialog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
Example 1: Repeated Parameterization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
Example 2: Simulating Linear Motion. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
Example 3: Simulating Rotary Motion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 197
Example 4: Using a Program to Simulate Motion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 200
Example 5: Simulating a Working Mechanism. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 202
Plotting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 204

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Other Applications 205

MEDUSA Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 206
Parametric Design and 3D Modelling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 207
Parametric Design and Sheet Metal Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
Appendix A Parametric Design Element Defaults 213
Basic Parametric Elements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 214
Tables, Symbols, Groups and Error Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 215
Graphical User Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 216
Appendix B Error and Warning Messages 217

List of Figures 225

Index 229

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PREFACE

Book Conventions

The following table illustrates and explains conventions used in writing about MEDUSA applica-
tions.
Convention Example Explanation
Menu Choose Zoom from the View menu Indicates a command, function or
Add button button that you can choose from a
Choose the tool Creates thin solid lines. menu, dialog or tooltray.
Syntax acos 0.345 User input,
The ciaddobj command commands, keywords and
Return or Control-g keys to press on a keyboard.
SyntaxBold Enter command> plot_config Where system output and user input
are mixed, user input is in bold.
SyntaxItalic tar -cvf /dev/rst0 filename Supply an appropriate substitute for
each variable; for the given example
replace filename with an actual file
name.
Filename&path medusa\med2d\m2d\src\ Shows path and filenames.
UPPERCASE MEDUSA or CADCONVERT Names of products.
italic left mouse button Indicates the buttons to press on a
Drafting User Guide mouse and names of books.
bold A temporary group is a collection of ... Emphasize text.

Please note: Illustrations showing menus and forms are taken from a window system.
The display for other platforms can differ slightly.

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Preface

Online User Documentation

Online documentation for each book is provided in HTML format. You can view this online
documentation in the installation directory, on the CD-ROM, or directly by calling it up within the
MEDUSA user interface.

Installation Directory
1. Navigate to the directory where MEDUSA is installed.
<MEDUSA installation directory>/meddoc/doc/<language>/ (Unix)
<MEDUSA installation directory>\meddoc\doc\<language>\ (Windows)
where <language> is either english, german or french.
2. Click on the file mainmenu.htm.
3. Click the book title you want to view.

CD-ROM
1. Navigate with your HTML browser to the CD-ROM into the following directory.
<CDROM_mount_point>/doc/<language>/ (Unix)
<CDROM_Drive>:\doc\<language>\ (Windows)
2. Click on the file mainmenu.htm.
3. Click the book title you want to view.

MEDUSA Interface
1. Click left on the entry Help inside the main menu.
2. Choose MEDUSA Documentation from the pulldown menu.
A browser opens showing the mainmenu.htm listing all available documents.

Printing Documentation

A PDF (Portable Document Format) file is included for each online book. See the first page of
each online book for the document name which corresponds to the PDF file name (e.g. HTML
title is Drafting User Guide, PDF file is drafting.pdf). Check with your system administrator if you
need more information. You must have Acrobat Reader installed to view and print PDF files. If
you don‘t have the Acrobat Reader, you can download it for free from the Adobe homepage:
http://www.adobe.com/products/acrobat/readstep.html

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 MEDUSA4 Parametrics

INTRODUCTION

This chapter introduces the MEDUSA Parametric Design system.

• What Is Parametric Design? .................................................... 10

• How Parametric Design Works ................................................ 14

• Tooltray .................................................................................... 23

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MEDUSA4 Parametrics
Introduction

What Is Parametric Design?

MEDUSA Parametric Design is a system for scaling, or reconfiguring, the size and shape of
part geometry according to a defined set of dimensions, or parameters. In MEDUSA 2D, you
change the shape of an object using one of the transformation tools such as magnify or shrink,
mirror, or rotate, or by redrawing it completely. Using Parametric Design, you change the shape
of an object by changing its dimensions, pulling and stretching the geometry into another shape.
You can use Parametric Design to do any of the following:
• Reconfigure the geometry of a part
• Create families of parts where one general case of a part is defined with a set of
dimensions that you can vary
• Create libraries of symbols
• Simulate the action of mechanisms

Reconfiguring the Geometry of a Part

Parametric Design is used primarily to change one or more dimensions of an object on a sheet
to make either fine adjustments to a design or radical changes to a drawing.
For example, the master drawing of the part shown in the figure below has three dimensions.
Any of these can be changed to produce a new shape. If required, all three dimensions can be
changed.
Figure 1 Changing the Dimensions of an Object

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 MEDUSA4 Parametrics
What Is Parametric Design?

Creating Families of Parts

The Parametric Design system makes it easy to produce families of parts, where components
which have similar functions but vary in shape and size. A good example is a set of spanners of
various sizes.
Figure 2 shows another example, a set of brackets. Parametric Design allows you to produce a
whole family of parts automatically from a single master drawing using a set of dimension vari-
ables.
Figure 2 A Family of Parts Made From a Single Master Drawing

Creating Symbol Libraries

You often need to load standard symbols onto a MEDUSA sheet. Using Parametric Design, you
can create libraries of parametric symbols to suit a range of different applications without having
to redraw the symbol each time.

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MEDUSA4 Parametrics
Introduction

This example shows a master drawing of a tab and some of the results obtained by loading the
symbol with different relative dimensions.
Figure 3 A Symbol Library Created Using Parametric Design

By adding a table of dimensions to the master drawing, all the required sizes may be pre-
defined. In this way you can produce a drawing of a particular size of component simply by
selecting a set of dimensions from the table.

Simulating Mechanical Movement

You have seen how you can use Parametric Design to change the size of an object on a sheet.
By progressively altering one or more dimensions and redrawing the new view over the old, you
can create an impression on the screen which simulates the movement of a mechanism. You
can then investigate potential collisions as the components move and reciprocate. For example,
Figure 4 shows a simulation of the motion of a lift arm assembly for a loader shovel.

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What Is Parametric Design?

Figure 4 Simulation of the Movement of a Lift Arm Assembly

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MEDUSA4 Parametrics
Introduction

How Parametric Design Works

Parametric Design places some or all of the points that make up an object onto a grid. The grid
is moved according to the parameters you specify, either angles or lengths, and this process
pulls the points of the object to their new positions.
To use Parametric Design, you do the following:
1. Create a parametric viewbox around the object you want to parameterize.
2. Define a reference point that will remain static during parameterization.
3. Decide if all or only part of the object needs to be parameterized.
4. Dimension the object using MEDUSA dimensioning facilities to place relevant object
points on the grid.
5. Check that all the moveable points of the object lie at grid intersections.
6. Exclude some parts of the object from parameterization, if you want to.
7. Enter new parameters.
8. Execute the Parametrization that moves the grid.
9. Check the result.

Viewboxes

Before you can parameterize any geometry, you must place a parametric viewbox on the sheet
around the geometry.
A parametric viewbox is a closed line of type LPV, consisting of straight line segments. Only ele-
ments wholly within a viewbox are affected by Parametrization. Viewboxes have the following
features:
• They may be any shape
• They must not overlap or be nested
Viewboxes are processed in turn independently of one another, in the order that you place them
on the sheet. The maximum number of viewboxes allowed per sheet is 20.
Figure 5 Examples of Parametric Viewbox Shapes

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 MEDUSA4 Parametrics
How Parametric Design Works

Reference Points

The geometry that you intend to parameterize must have a datum or reference point. This is the
point from which all movement occurs. The reference point remains fixed on the sheet during
parameterization. You can use intersecting static baselines or a prim to specify a reference
point.

Static Baselines

One way of specifying a reference point is using a pair of intersecting static baselines. A base-
line is a line of type LBL. A static baseline has static points (FUNV0) at each end. You would
normally draw a horizontal baseline and a vertical baseline through the geometry. The intersec-
tion of these two lines is the fixed reference point which does not move during parameterization.
Figure 6 Intersecting Static Baselines

Intersecting static baselines such as those shown above in Figure 6 generate six grid lines, of
which you can normally see just two. Each baseline supports three grid lines: one along its
length, and two at the ends of the line, perpendicular to it. The default length of these perpen-
dicular grid lines depends on the grid tolerance. The default grid tolerance is 0.1 mm, so you
cannot normally see these grid lines at all.

PVG Prims

Another way to specify a reference point is using a prim of type PVG. The datum of the prim is
the reference point. Horizontal and vertical grid lines are generated through the datum.
Figure 7 The Parametric Design Datum Prim (Type PVG)

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MEDUSA4 Parametrics
Introduction

Orthogonal View Prims

You can also use an orthogonal view prim to specify a reference point. The datum of the prim
acts as a static reference point and grid lines are generated along the arms of the prim. A
worked example showing how to use a view prim as a reference point is given on ”Getting
Started”, “Example 1: Using a Prim” on page 53.
Figure 8 Orthogonal View Prims

Positioning Reference Points

Choosing the right place for a reference point is not always easy. The reference point should
usually be at the point from which you would choose to dimension your drawing. In general, a
good reference point is a central point on a line of symmetry, for example the center of a circle.
Do not choose a point which should move during parameterization.

Static baselines: Static baselines can be drawn at any orientation although they are frequently
at right angles, as shown in Figure 9.
Figure 9 Positioning Baselines

Figure 9 (a) The center of the circle is also the center of symmetry. This makes an ideal
reference point.
Figure 9 (b) If the component lies at an angle, draw the baselines at the same angle, so
that they lie along lines of symmetry.
Figure 9 (c) The bottom left point is a suitable reference point because it is used when you
dimension the width and length. Any point from which dimensions are
measured is a useful reference point.

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 MEDUSA4 Parametrics
How Parametric Design Works

Prims: Figure 10 shows some examples of how you might position a prim in relation to object
geometry. You can use a PVG prim or an orthogonal view prim.
Figure 10 Positioning a Prim

Figure 10 (a) The datum point of the prim is placed precisely at the bottom left corner point of the
object. Grid lines are generated in the direction of each arm.
Figure 10 (b) If the component lies at an angle, adjust the prim so that its arms run along the
lines of the component. To do this, position the prim in its normal orientation then
rotate it until it aligns with the component.
Figure 10 (c) Make sure that at least one of the arms of the prim lies along an existing line. This
helps when the grid is drawn at a later stage.
Figure 10 (d) It is perfectly valid to place a prim at a center of symmetry. Notice that this PVG
prim does not lie on any existing lines.
Figure 10 (e) You may sometimes need to add supporting lines to help create the grid. In this
example, two dashed lines have been added.

The Parametric Grid

Parametric Design works not by moving individual points but by moving a grid upon which all
moveable points are placed. The grid consists of lines at any angles and also of circles. It is not
a regular orthogonal grid like the construction grid in the 2D drafting system.

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Introduction

Grid Lines

Parametric grid lines are frankfurter lines, type STK, and can be oriented at any angle and spac-
ing. They are drawn on top of existing lines in your drawing. If your drawing contains diagonals,
arcs, or circles then grid lines are also drawn in the shape of diagonals, arcs, or circles.
Figure 11 Parametric Grid Lines

Dimensions and the Grid

You place moveable points upon the grid by dimensioning them. Each dimensioned point in the
object geometry is fixed to a grid line intersection. Points that are fixed to grid intersections
move with those grid intersections during parameterization.

Looking at Grid Lines

It is very useful to look at the grid that has been calculated each time you create a new dimen-
sion group. This enables you to see if the drawing has been adequately dimensioned.

Geometric Tolerance

The system uses a geometric tolerance or grid tolerance to match object points to grid line
points. The default tolerance is very small (0.1 mm) and you are advised not to change it.

Some Special Drafting Techniques

You can use any MEDUSA drawing as input to the Parametric Design system. However, you
should be aware that you cannot always draw and dimension an object in the normal way and
then parameterize it. You may need draw an object in a particular way to avoid constraining the
movement of points during parameterization.
This section describes some of the ways you can avoid placing unnecessary constraints on the
way geometry is transformed during parameterization. Constraints can occur if you have either
coincident or collinear points in the master drawing:

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How Parametric Design Works

Avoiding Coincident Points

Coincident points in object geometry can cause problems for Parametric Design. If you create
points on top of each other in the master drawing, these points will remain coincident whenever
you parameterize the drawing. The result may not be what you intend. If there are small details
in your drawing, such as fillets, it is best to exaggerate them or the distance between them. This
ensures that points are not coincident. The system uses a geometric tolerance to decide
whether or not two points are coincident.
Figure 12 shows how you might want to parameterize an object. The drawing on the right can
only be generated from the master drawing on the left if the master is drawn correctly.
Figure 12 Possible Parameterization

Figure 13 shows the fillet detail and illustrates how to solve the problem of coincident points.
Figure 13 Avoiding Coincident Points

In this example, if you draw two 3 mm radius fillets in an 8 mm gap, the end points are com-
pletely separate. This allows you to move the points apart during parameterization, as in
Figure 12. However, if you create the 3 mm fillets in a 6 mm gap, the end points are coincident
and are locked together. The points cannot move apart during parameterization, and therefore
you cannot parameterize the object freely.
Figure 14 shows another example. Here, there are two versions of the master drawing of a
mechanism in which a piston is required to move up and down a cylinder.

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Introduction

Figure 14 Coincident Points

In Figure 14 (a), the piston cannot move during parameterization because its top two points are
coincident with the points at the top of the cylinder. To allow the piston to move freely you must
draw the piston in the position shown in Figure 14 (b).

Collinear Points

Points are considered to be collinear if a straight line can be drawn through them. During
parameterization, collinear points which lie along the same grid line remain collinear even if you
attempt to change their orientation during parameterization. The following example illustrates
this.
Figure 15 shows geometry containing several collinear points. The vertical dimension gener-
ates grid lines running in the same direction as the dimension leader lines. The grid lines appear
as frankfurter lines (line type STK).
Figure 15 Collinear Points on the Same Grid Line

Any points lying along these grid lines are kept collinear during parameterization. This means
that it is not possible to parameterize the drawing to produce the shape shown in Figure 16.
Points 3 and 4 must remain collinear with points 1 and 2. The same restriction applies to points
lying along the lower grid line in Figure 15.
Figure 16 Aim of Parameterization

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How Parametric Design Works

How Geometric Properties are Maintained During Parameterization

Geometric properties are automatically preserved during parameterization. For example, lines
that are perpendicular are kept perpendicular. Tangential lines remain tangential. For example,
in Figure 1, “Changing the Dimensions of an Object” on page 10, the straight line segments
remain tangential to the arcs whenever this component is parameterized.
Horizontal and vertical lines also remain in the same orientation. In Figure 17, horizontal and
vertical properties of the master drawing are maintained whenever the object is parameterized.
Figure 17 Example of Parameterizing a Specific Case

By rotating the master drawing before parameterizing it, you can produce several versions of
the master, in a variety of shapes and orientations. For example, the master drawing in
Figure 18 has been rotated by a few degrees and consequently there are no horizontal or verti-
cal lines. You can now produce any sized or shaped variant of the original object by parameter-
izing the master drawing. Notice that this method also allows you to create new objects with
vertical or horizontal sides.
Figure 18 Example of an Ideal Master Drawing

In many cases a horizontal master drawing may be sufficient. It is only when you need to rotate
the drawing during parameterization that the master drawing must be drawn at an angle. This is
particularly important when creating parametric symbols or when simulating mechanical move-
ment. In these situations objects frequently need to be rotated as they are parameterized.

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Introduction

Special Cases

As shown above, a master containing horizontal and vertical lines may be treated as a special
case. Restrictions can also be caused by lines drawn at angles of 30, 45, and 60 degrees.
These are also regarded as special cases. So if you need to rotate the master drawing, use a
fractional angle, such as 13.5 degrees. This ensures that the rotated drawing contains no lines
at angles which are regarded as special cases. If a drawing fails to parameterize, always check
for special cases, particularly the angles of the lines in the drawing.

Always Parameterize the Master Drawing

When you parameterize geometry, always use the master drawing. You may not be able to
parameterize a drawing which is itself a parameterized version of the master. This is because a
drawing produced by parameterization may contain restricting features not present in the mas-
ter drawing. These might be coincident points or lines, or lines at particular angles, or any of the
other special cases mentioned above.
If you want to produce several parameterized versions of an object, create the master drawing
and save the sheet. To produce the first parameterized version, take the master drawing and
parameterize it. The new version must be stored under a new name, so rename the sheet and
save it. To produce the second parameterized version of the object, and all subsequent ver-
sions, reload the master drawing and parameterize it with new parameters each time.

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Tooltray

Tooltray

Please note: Before you can work with 2D Parametrics, you have to activate the license by
choosing Licenses -> 2D Parametrics inside the main menu bar.

The following figure shows the tooltray available inside the graphical user interface of
MEDUSA.
Figure 19 2D Parametrics Tooltray

Undo Control Parametric Layers

Parameterize Grid

Create Reference Point Create Viewbox

Create group lines and PPG prim

Creates parametric symbol Parametric Switches and command

attachment text

Query and modify LCIS variables Creates user LCIS variables

Display the current settings Modify selected dimension text

of the parametric line styles

Tables Sets options for fillet behavior

CPI Named Groups Tolerance Settings

Display Post Param Dialog Select and parameterize variant

Details on most of the tools is given in the following chapters.

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Introduction

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 MEDUSA4 Parametrics

DIMENSIONING

This chapter describes how to prepare a drawing for parameterization by dimensioning the
object geometry. This places the object points onto a parametric grid.

• Dimensions in Parametric Design............................................ 26

• Tolerance Definition ................................................................. 29

• Linear Dimensions ................................................................... 32

• Circle and Arc Dimensions....................................................... 34

• Over-dimensioning and Under-dimensioning........................... 36

• Change Dimension Text........................................................... 38

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Dimensioning

Dimensions in Parametric Design

To place points onto grid intersections you must dimension them. You can dimension all or only
part of an object, but all points which are to move must be dimensioned. Points that are not
dimensioned generate an error message during parameterization.

Dimension Types You Can Use

Normal dimensioning methods do not always work when using Parametric Design and there are
some dimension types that you cannot use. You can use any of the following dimension types to
prepare a drawing for parameterization.
• Chain
• Coordinate
• Datum
• Angular
• Radial
• Diameter
Dimensions with tolerances may be parameterized normally. Dual unit dimensions can also be
parameterized.

Dimension Types You Cannot Use

You cannot parameterize geometry that has been dimensioned with either of the following
dimension types:
• Axonometric dimensions
• Tolerance limit dimensions (LIM)
If you try to parameterize drawings that contain axonometric or tolerance limit dimensions, you
will see the following error message:
Illegal dimension type
Refer to the MEDUSA Parametric Design Reference Guide for details of how to convert tole-
rance dimensions into a format that can be parameterized.

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Dimensions in Parametric Design

Dimensioning Techniques

When you dimension geometry which will be parameterized, use the following guidelines:
• Always use near probes to create the dimension construction line, except for the first
point which can be created with any kind of probe.
• Start by dimensioning points in relation to the reference point. This allows the grid to
grow outwards from the reference point.
For every new dimension group you create, one of the points you are dimensioning must
already lie at a grid line intersection. The exception to this rule is if you are using chain dimen-
sioning, where you can use center support to place points on the grid (see ”Linear Dimensions”,
“Center Support” on page 32).

Example

The reference point in Figure 20 generates two grid lines, one horizontal and one vertical,
through the datum of the prim. Point A coincides with the reference point, and therefore it is at a
grid intersection. Points B, C, and D must be placed at grid intersections by dimensions.
Figure 20 Grid Lines Generated By Reference Point

Dimensioning the line AB places point B on the grid, as shown in Figure 21.
Figure 21 Extra Grid Intersection Generated by Dimensioning Line AB

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Dimensioning

When the line BC is dimensioned as in Figure 22, all the points of the object lie at grid intersec-
tions and are said to be supported on the grid.
Figure 22 Grid Completed by Second Dimension

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Tolerance Definition

Tolerance Definition

This section shows you how to create permissible upper and lower tolerance for dimensions.
For this you can define variable tolerances and its usage for parameterization.

Toolset

Figure 23 Toolset for Tolerance Settings

The tools are:

Displays the current tolerance settings
opens the dialog PAR VAR Setting,
which allows you to define tolerance settings for the
current MEDUSA session. For details see “Dialog PAR VAR Setting” on page 30.
Creates parametric tolerance text
opens the dialog PAR VAR Setting, which allows you to place texts on the sheet, which
define the usage of variable tolerances.
Figure 24 Dialog for Placing Tolerance Setting Texts

From left to right the succession of switches is the same as it is in the dialog PAR VAR
Setting from top to bottom, explained below.

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Dimensioning

Dialog PAR VAR Setting

PAR VAR Settings are used for specifying how the system calculates new dimension values
during parameterization for those dimensions, which have upper and lower tolerances defined.
The following dialog opens if you click left on the tool Displays the current tolerance settings.
Figure 25 Dialog for Tolerance Settings

The following list explains the options:

Option PAR VAR Explanation Example
OFF Specifies that any changes made to the original
tolerance text are ignored. The original tolerance
appears in the parameterized drawing.

VAR Ensures that any expressions which have replaced

original tolerance text are evaluated during
parameterization. The resulting value is used to
calculate the new dimension and resulting values are
placed in the new dimension. This is the default setting.
LIM Converts VAR tolerance dimensions to LIM format. The
new tolerances are calculated by evaluating the original
tolerance texts and add them to the nominal value.

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Tolerance Definition

Option PAR VAR Explanation Example

MIN Specifies that the lower tolerance is used for all
tolerance dimensions. In some cases, such as holes,
you may need to indicate maximum or minimum
diameters explicitly. You can do this by editing the
individual tolerance texts.
MAX Specifies that the upper tolerance is used.

MID Calculates the tolerance using the following formula:

(MAX - MIN) * 0.5 + MIN
RANGE Calculates the tolerance using the following formula:
(MAX - MIN) * factor1 + MIN + factor2
factor1 must be a factor in the range 0 to 1. factor1=0.5
factor2 is an optional extra factor which can get any no factor2
value. If it is left out it is set to 0.

All the options are explained in detail in the Parametrics Reference Guide, chapter „Dimension-
ing“.

Create Variable Tolerances

For creating variable tolerances do the following steps:

1. Select a dimension.
2. Open the properties window with the right mouse button.
3. In the section Dimension and Tolerance style on top of the dialog choose the icon Tolerances
shown as dimensions plus variations.
In the bottom of the dialog the entry fields below Tolerance become active.
4. Type in the expression for the upper tolerance in the upper field (e.g. A+B).
5. Type in the expression for the lower tolerance in the lower field (e.g. A-B).
At this step we assume that the variables A and B are defined inside the sheet as
command texts of style Parametric command text, e.g. LET A=7 and LET B=3.
6. Choose the button OK for applying the settings and closing the properties dialog.
7. Now define the variable tolerance settings. You have the following options:
a. Choose the tool Displays the current tolerance settings for defining the tolerance settings for
the MEDUSA session.
b. Choose the tool Creates parametric tolerance text for placing the tolerance definitions on
the sheet. Such a text overrides the settings inside the dialog PAR VAR Setting.
8. Now you can parameterize your geometry (see ”Getting Started”, “Parameterizing an
Object” on page 50).

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Dimensioning

Linear Dimensions

Linear dimensions, for example chain or datum, generate grid lines along the leader lines.
When you create linear dimensions, the end points of the dimension must be at grid line inter-
sections. The placement point does not need to be at a grid line intersection. Figure 26 shows
the significant points of a linear dimension.
Figure 26 A Linear Dimension

2
endpoints of dimension leader line

1 3
leader line dimension line placement point

Which Dimensions Types To Use

Horizontal and vertical: Use horizontal and vertical dimensioning only if the part of the object
being dimensioned is to remain horizontal or vertical.

Parallel and perpendicular: If you intend to rotate an object during parameterization, use par-
allel or perpendicular dimensioning. This is important when working with parametric symbols,
which are often rotated as they are loaded (see “Symbols” on page 133).

Center Support

Normally, you dimension geometry outwards from the reference point. If the reference point
does not lie on a line of geometry, but instead lies at a center of symmetry then you can create
certain chain dimensions using center support. This means that the reference point does not
have to be specifically dimensioned. Center support is possible when an existing grid line per-
pendicular to the dimension passes through the center of the dimension.
In the example in Figure 27, the reference point is the intersection of two static baselines. A hor-
izontal baseline passes through the center of diameter dimension on the left and does not coin-
cide with any lines of geometry.

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Linear Dimensions

Figure 27 Object With Intersecting Baselines

To dimension the diameter on the left of the object in Figure 27 from the reference point you
would need to use a three point dimension construction line including points A and B and the
reference point. Using a chain dimension you can use a two point construction line from points
A to B. Figure 28 shows how the diameter dimension is supported by the horizontal baseline.
Figure 28 Chain Dimensioning With Center Support

Datum and Coordinate Dimensioning

Datum and coordinate types of dimensioning can only be drawn horizontally or vertically and so
you should not use them when an object is in a rotated position or will be rotated at a later
stage.
Unlike chain dimensions, datum and coordinate dimensions cannot use center support.

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Dimensioning

Circle and Arc Dimensions

You can create circle and arc dimensions in the usual way.
For fillets, you can dimension each fillet individually or you can use the PARFIL in-sheet com-
mand to set fillet dimensions automatically during parameterization. This offers the advantage
that the whole geometry can be parameterized with its fillets without dimensioning each fillet
individually
2D Parametrics provides the following dialog for defining filleting settings for undimensioned fil-
lets. It is opened by the tool Sets options for fillet behavior during parameterization :
Figure 29 Dialog for Filleting Settings

Please note: The options of the dialog are valid for undimensioned fillets. Fillets which have a
dimension or for which dimensions are set automatically with a PARFIL command
are parameterized as defined.

Keep
If there is no dimension for the fillet, it is taken without changes.
Explicit
(default) If this option is chosen only those fillets are parameterized which have a value
or expression defined explicitly, e.g. with a PARFIL text (see example on the next
pages). Undimensioned fillets produce error messages.
Set All
If set, undimensioned fillets get the defined Radius.
Set Max
If set, undimensioned fillets which are smaller than or equal to the Maximum Radius are

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Circle and Arc Dimensions

taken without changes. Undimensioned fillets which are larger are set to Maximum
Radius.
Set Less Than
If set, undimensioned fillets which are smaller than or equal to the Maximum Radius get
the Radius.
Radius
is the value used for undimensioned the fillets for the options Set All and Set Less Than.
Maximum Radius
is the maximum value for undimensioned fillets used for the conditions Set Max and Set
Less Than.

Please note: You find a complete example for parameterizing components with fillets in chapter
”Simple Parameterization Examples”, “Example Two” on page 68.

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Dimensioning

Over-dimensioning and Under-dimensioning

When you prepare a drawing for Parametric Design, it is important that all the points you want to
scale are placed onto the grid using dimensions. However, it is possible to over-dimension an
object so that conflicts prevent the Parametric Design system from working correctly. Similarly, if
the object is under-dimensioned, you will not be able to parameterize it.

Under-dimensioning

Under-dimensioning means that you have not dimensioned all the points in the geometry and,
therefore, there are some points that are not on the grid. Adequate dimensioning ensures that a
grid line is drawn on top of every line in the object, and that every point lies at a grid line inter-
section. If you try to parameterize a drawing which is inadequately dimensioned, you receive
the following error message on the sheet with its datum at the offending point:
Point not dimensioned
Figure 30 shows some examples of objects which are under-dimensioned and the error mes-
sages resulting from trying to parameterize these objects with new dimension parameters.
Figure 30 Examples of Under-Dimensioned Drawings

Neither of these could be parameterized because not enough dimension information is pro-
vided:
Figure 30 (a) The apex point is not dimensioned.
Figure 30 (b) The position of the top right point is uncertain.

You cannot draw these shapes from the information provided. Therefore Parametric Design
cannot draw them either.

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Over-dimensioning and Under-dimensioning

Over-dimensioning

It is a common error to dimension an object so that some of the object points are located at an
intersection of more than two grid lines. You will realize that you have made a mistake when you
try to parameterize the object. You will receive the following error message written onto the
sheet with its datum point indicating the problem point:
Ambiguous construction
Figure 31 shows some examples of objects which have been over-dimensioned and the error
messages resulting from trying to parameterize them. In both cases, it is possible to specify val-
ues for the dimension variables which would make the objects impossible to draw.
Figure 31 Examples of Over-dimensioned Drawings

In both of these cases, too much information is given:

Figure 31 (a) Any changes to the angle dimensions could conflict with the linear dimensions.
Figure 31 (b) The sum of dimensions len3 and len4 must equal len2.

Dimensioning Hints

To avoid over-dimensioning, study the geometry and plan dimensions carefully. Keep in mind
that each object point needs to lie at a simple grid intersection of no more than two grid lines.
You must give enough information for the whole of the drawing to be created without conflict or
ambiguity.

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Dimensioning

Change Dimension Text

If you want to change texts of dimension groups, for example to replace numerical values by
variables or re-name a variable, the tool Change selected dimension text is provided.
Please consider the following when using this tool:
• When selecting several dimension groups only texts in the first selected group are
changed.
• Only texts will be replaced, which have the text string found first in the dimension
group. Texts with other strings remain unchanged.
• If the first dimension text differs from the others, only this first text will be changed.
Following steps show how to change texts of a selected dimension:
1. Select a dimension.
2. Choose the tool Change selected dimension text .
The following dialog opens:
Figure 32 Dialog for Changing Texts

3. Enter the new text.

4. Switch on the option Replace same text over whole dimension group.
If this option is off, only the first text in the dimension group will be replaced.
5. Click left on the button OK or Apply.
In both cases the change of texts is executed. OK additionally closes the dialog. With
Apply the dialog remains open.

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GETTING STARTED

This chapter contains two simple examples which show you how the MEDUSA Parametric
Design system works. Before working through the examples in this chapter, you should have
read about viewboxes, reference points and grid lines in ”Introduction”, “How Parametric Design
Works” on page 14.

• Overview .................................................................................. 40

• Creating a Viewbox.................................................................. 41

• Creating a Reference Point...................................................... 43

• Dimensioning ........................................................................... 45

• Building the Parametric Grid .................................................... 46

• Examining the Parametric Grid ................................................ 48

• Entering Your Own Parameters ............................................... 49

• Parameterizing an Object ........................................................ 50

• Example 1: Using a Prim ......................................................... 53

• Example 2: Using Baselines .................................................... 57

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MEDUSA4 Parametrics
Getting Started

Overview

The following procedure gives an overview for simple parameterization of a part. You can per-
form steps 1 through 4 in any order.
Step Action What You Do
1 Draw the object you want to parameterize. Use any line type.
Enclose the objects you wish to scale with
2 Draw a parametric viewbox on your sheet. a line of type LPV. See “Creating a
Viewbox” on page 41.
Place a prim or two intersecting baselines
Define a datum or reference point which
3 at your chosen reference point. See
will remain static during parameterization.
“Creating a Reference Point” on page 43.
Dimension the component. See
4 Place all object points on the grid.
“Dimensioning” on page 45.
See “Building the Parametric Grid” on
Check that the grid supports each of the
5 page 46 and “Examining the Parametric
points to be scaled.
Grid” on page 48.
Place the new value into the text edit field.
Give new values for the dimensions you
6 See “Entering Your Own Parameters” on
want to change.
page 49.
Use temporary parameterization until you
are satisfied with the parameterized
7 Parameterize the object.
drawing. See “Parameterizing an Object”
on page 50.

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Creating a Viewbox

Creating a Viewbox

Before you can use the Parametric Design system you must have a sheet displayed on the
screen. The sheet must contain a viewbox which surrounds the object you intend to parameter-
ize. If you use a standard drawing sheet, the sheet may already contain a viewbox. The viewbox
may be difficult to see at first because it coincides with the outline of the sheet, and some parts
of it are invisible.

Toolset

The following figure shows the toolset for creating view boxes.
Figure 33 Toolset for Creating Viewboxes

The tools are:

Creates parametric viewbox lines
Creates parametric viewboxes
Both tools create a line of style Parametric view line, type LPV. This line encloses the
geometry which shall be parameterized.

How to create a viewbox

If you are not using a standard sheet, or if your standard sheet does not have a viewbox, you
must create a line of type LPV and draw a viewbox for yourself. Use the tools given above. The
viewbox can be of any shape, as shown below.
Figure 34 Examples of Parametric Viewbox Shapes

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MEDUSA4 Parametrics
Getting Started

Placing geometry inside the viewbox

When the drawing is parameterized, only those parts of the drawing inside the viewbox are
affected. The geometry which you intend to parameterize must be completely inside the view-
box. All dimensioning, grid lines, and baselines must also be inside the viewbox.

Please note: Note that after parameterization all elements should be still inside the view box
otherwise you get error messages for those parts which leave the view box.

Number of viewboxes

You can place up to 20 viewboxes on a sheet, but they must not overlap or be nested. Each
viewbox is processed separately.

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Creating a Reference Point

Creating a Reference Point

The geometry that you intend to parameterize must have a datum or reference point. This is the
point from which all movement occurs. The reference point remains fixed on the sheet during
parameterization.

Toolset

The following figure shows the toolset for creating reference points.
Figure 35 Toolset for Creating Reference Points

The tools from left to right are:

DXY prim to act as a static reference point
attaches a DXY prim to the cursor for placing as reference point for parameterization.
PVG prim to act as a static reference point
attaches a PVG prim to the cursor for placing as reference point for parameterization.
Creates static base lines
activates line creation and opens the following dialog:
Figure 36 Parametric Point Function

The point functions in this dialog are disabled until you placed the first point of the base
line by probing into the sheet. If you have done this, the point functions are enabled.
A point function is always applied to the point you have drawn last.
If you probed the first point of a baseline and then choose a point function, it is not
applied to the first point until you have drawn the second point.

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Getting Started

If you probed the second point and then choose a point function, the function is applied
to the current second point immediately. This is also valid for all further points of the
baseline.
For details on the meaning of the point functions, see the next section.

Point Functions

The point functions at the ends of baselines indicate how the geometry is constrained when the
drawing is parameterized.
The available point functions are:
Perpendicular
Perpendicular point, point function FUNV 10.
This point function guarantees that the corresponding segment on which it is placed is
perpendicular to the element segment on which the starting point of the appropriate
baseline is.
Tangent
Tangent point, point function FUNV 12.
This point function guarantees that the segment on which it is placed is tangential to
the element segment on which the starting point of the appropriate baseline is.
Circle Center
Circle Center point, point function FUNV 26.
This point has to be on a grid line and it marks the center of a circle.
Intersection
Intersection point, point function FUNV 11.
This point marks an intersection of existing grid lines.
Standard
Static point, point function FUNV 0.
If this point function is at both ends of a line it is a static baseline, which does not move
during parameterization.
Details and examples for the point functions are given in the Parametrics Reference Guide,
chapter „Geometric Constraints“.

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Dimensioning

Dimensioning

For parameterizing geometry you need to dimension it and then replace the dimension texts
either with new values or expressions. For details on dimensioning see the appropriate chapter
in the MEDUSA Drafting Guide.
Dimensioning for parameterization was already explained in “Dimensioning” on page 25.

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MEDUSA4 Parametrics
Getting Started

Building the Parametric Grid

Grid lines are generated first through any reference points in the drawing, through the prim
datum or along the static baselines. Then they are generated through points that you have
dimensioned.

Toolset

The following figure shows the toolset for drawing grids.

Figure 37 Toolset for Drawing Grids

The tools from left to right are:

Draws complete circular lines for arcs
Draws tangent lines for all tangent arcs
Draws grid lines over fillets affected by PAR FIL
This tool works only on tangent arcs and if a parametric command PAR FIL exists. It is
not applicable on circular arcs.
Draws the grid corresponding to the original drawing
Displays the grid built up from the reference point and any dimensioning. Grid lines are
frankfurter-shaped lines on layer Graphical Error Messages and they are drawn over the
geometry. Grid lines created with this tool are placed permanently on the sheet but you
can delete them with the tool Parametric Layers (see ”Layers and Parametric Switches”,
“Parametric Graphics Control” on page 111).
Draws the potential grid
Displays the grid built up from all lines inside the viewbox. Grid lines are frankfurter-
shaped lines on layer Graphical Error Messages and they are drawn over the geometry. Grid
lines created with this tool are placed permanently on the sheet but you can delete
them with the tool Parametric Layers (see ”Layers and Parametric Switches”, “Parametric
Graphics Control” on page 111).
Draws baselines inferred when the baseline switch is on
This tool makes visible constraints which are used automatically for parameterization.
If you want, the drawn baselines can remain inside the drawing.
Draws lines connecting all collinear straight lines
This tool creates lines connecting collinear not-overlapping line segments. Lines drawn
with this tool are temporary. Refreshing the graphics deletes these lines.
Draws lines along all segments and completes circles for arcs
Lines are drawn along each segment finishing at the viewbox. Arcs are represented by
their appropriate circles. Lines drawn with this tool are temporary. Refreshing the
graphics deletes these lines.

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Building the Parametric Grid

Draws the new grid using parameters specified

Grid drawn with this tool corresponds to the parameterized (new) geometry.
Draws the grid corresponding to the original drawing and undoes it
Works the same way as the tool Draws the grid corresponding to the original drawing but grid
lines remain visible only until you refresh the screen.
Sequences through the grid lines
This tool assumes that you already have drawn a grid, for example with the tool Draws
the potential grid.
This tool is used for showing the built of a grid. It displays the grid lines one after
another. If you choose this tool a dialog opens. In there, each time you click on the
button Next a further grid line is displayed in addition to already drawn ones. Each time
you click on Previous an already drawn grid line is removed. If you click on Start, all grid
lines are removed and you are back at the beginning of building the grid, before
drawing the first grid line.
Details on using this tool are given in “Examining the Parametric Grid” on page 48.

When to draw the grid

You can dimension a drawing one step at a time, displaying the grid at each stage, or you can
dimension the whole of the drawing then draw the grid as a final check.
Throughout this manual, the grid is displayed after each new piece of dimensioning is added.
This is to help you to understand how grid lines are created. While you are learning to use the
system it is better to add one dimension at a time, and then use Draws the grid corresponding to the
original drawing and undoes it to display the grid so far.

Deleting grid lines

When you have checked to see that the grid is developing adequately, you should remove all
grid lines.
If you used the tool Draws the grid corresponding to the original drawing and undoes it for drawing the grid,
you only need to refresh the graphical area for deleting the displayed grid lines.
For the other tools use the Parametric Layers dialog:
1. Open the dialog Parametric Layers (see ”Layers and Parametric Switches”, “Parametric
Graphics Control” on page 111).
2. Switch on the option Grid Lines and click left on the button Delete.
The permanent grid lines are removed immediately.

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Getting Started

Examining the Parametric Grid

The following procedure will help you if you have any problems with building the grid or if you
want to see how the grid is developing. You may find it useful to perform them after you have
completed each example in this chapter. This diagnostic routine uses the tools Draws the grid corre-
sponding to the original drawing and Sequences through the grid lines (see Figure 37, “Toolset for Drawing
Grids” on page 46), so grid lines and any error texts are drawn permanently on the screen.
1. Refresh the screen with the Refresh Graphics tool from the toolbar to remove any
temporary grid lines.
2. Choose the tool Draws the grid corresponding to the original drawing to draw grid lines
permanently.
3. Choose the tool Sequences through the grid lines.
The following dialog opens.
Figure 38 Dialog Grid construction

• Click left on the button Next to display the first grid line. If you click left Next again, a
further grid line is drawn and so on.
• Click left on the button Previous to hide the currently displayed grid line. If you click
left Previous again, a further grid line is hidden. The button Previous is active until no
grid line is displayed anymore.
• Click left on the button Start to return to the beginning of examining grid lines. No grid
line is displayed.
• Click left on the button OK to close the dialog and display all grid lines.
4. You can remove the permanent grid lines as explained in “Deleting grid lines” on
page 47.

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Entering Your Own Parameters

Entering Your Own Parameters

Before you can create different parameterized versions of a component, you must replace the
original dimension text values with your own parameters.
In this section the value will be replaced by another value. But you also can use
• variables and expressions, which is explained in detail in “Variables and Expressions”
on page 91, and
• tables to store one or more groups of values on a sheet which is described in “Tables”
on page 117.

How to Enter Your Own Parameters

Use the following procedure to enter your own parameters:

1. Make the dimension text current.
2. Place the new dimension value into the text edit field below the dashboard.

Prefix and Suffix Texts

When you replace dimension values with your own parameters, be careful which text string you
alter. Dimension texts consists of the numeric value text and optional prefix or suffix texts.
These give you more information about the dimension, for example whether it is a radius or a
diameter:
• Prefix text is placed before the numeric value. Examples are R, DIA, and j.
• Suffix text is a separate text element (type TDM) placed after the numeric value, for
example the R and DIA texts in the ANSI dimensioning standard.
The Parametric Design system only uses the numeric value text when it calculates the new
dimensions of a component. You must replace this text with your own parameters. Prefix and
suffix texts are ignored when the dimension is evaluated and you can delete them if you want to
make the drawing clearer.

Dimensions After Parameterization

When the dimension is redrawn after parameterization, the dimensions appear in the style you
used originally. The value or expression you use to specify the new value does not affect the
final format, which will have prefix and suffix texts corresponding to the original drawing. For
example, you could replace a dimension of 25.0 DIA with the numeric value 40 (the DIA text
can be either ignored or deleted). After parameterization, the dimension appears as 40.0 DIA.

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Getting Started

Parameterizing an Object

When you have placed all of the object points onto the parametric grid by dimensioning them,
and replaced some of the dimension texts with your own parameters, you are ready to parame-
terize the geometry.

Toolset

The following figure shows the toolset for parameterization.

Figure 39 Toolset for Parameterizing

The tools from left to right are:

Parameterizes the geometry
Permanently parameterizes geometry inside the viewbox using the parameters you
have specified in the dimension groups. The geometry is stretched, shrunk or rotated
to fit the new values. The output is a drawing that is fully dimensioned.
Parameterizes the geometry then immediately undoes
Works the same way as the tool Parameterizes the geometry except that it is cancelled
immediately. The parameterized graphics remain visible on the screen until you refresh
the screen. Always use this tool until you are sure that you want parameterization to be
permanent. If you cancel the parameterization, you can experiment with different
parameters, returning the geometry back to its original shape each time
Simulates mechanism motion
opens the dialog for defining start and increment values for variables in order to do
several different parameterizations on a geometry. For details see “Simulating
Mechanisms” on page 189. Parameterization during simulation is done like using the
tool Parameterizes the geometry then immediately undoes.

Please note: The format of dimension text on the parameterized drawing is the same as in the
original drawing. Any prefix and suffix is retained and the original number of
decimal places is displayed regardless of the format you gave when you supplied
the new parameters.

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Parameterizing an Object

Parameterization Errors

If the drawing is satisfactory, each part of it will be highlighted on the screen as it is processed.
If there is a problem then one or more error messages of text type TS1 or TR1 will be placed on
the sheet so that the datum point coincides with the point that is causing the problem. This
enables you to identify any problem points and to correct the drawing. If an error message
appears, you must diagnose the problem and correct it before proceeding.
Error messages are placed on layer 99. Figure 40 shows two of them.
Figure 40 Error Messages

Common error messages

You will probably see the following two error messages frequently while you are learning to use
Parametric Design.
This message may appear when you use the tool Draws the grid
corresponding to the original drawing and undoes it . The reason is a
No supporting grid(s) point somewhere in the object which is not fixed to a grid
intersection. The datum of this error text is placed on the offending
point. This error is usually caused when, although you have
dimensioned a point, it is not at a grid intersection.
This message may appear when you use the tool Parameterizes the
geometry. The cause is an inaccurately dimensioned or completely
undimensioned point. Always investigate problem points by
Point not dimensioned zooming in to check that the dimensioning is accurate. You may
have to delete the dimensioning and draw it again. A typical cause
of inaccurate dimensioning is the failure to use near probes (where
they are required) when drawing a dimension construction line.

These are just two of the most common errors. A full list of possible error messages is given in
“Appendix B Error and Warning Messages” on page 217.

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Getting Started

Removing Error Messages

When you cancel a drawing grid or parameterization function immediately, any error messages
will disappear when you refresh the screen.
If you do not cancel the command, error messages are written onto the sheet permanently. To
remove them, delete the layer on which they are drawn, layer 99. Layer 99 contains grid lines
and error messages.
To delete permanent error messages:
1. Open the dialog Parametric Layers (see ”Layers and Parametric Switches”, “Parametric
Graphics Control” on page 111).
2. Switch on the option Grid Lines and click left on the button Delete.
The permanent grid lines are removed immediately.

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Example 1: Using a Prim

Example 1: Using a Prim

This example shows you how to parameterize a rectangle using a prim of type DXY as the ref-
erence point. The master drawing can be used to produce rectangles of any given size.
1. Draw a rectangle, as in Figure 41. The length of the sides is not important.

Adding a Reference Point

2. Create a prim by choosing the tool DXY prim to act as a static reference point from the tooltray
MEDUSA Parametric.
3. Position the new prim on a corner point.
The arms of the prim are aligned with the outline of the rectangle, so there is no need
to rotate the prim into a better position.
Figure 41 Example1: Rectangle with DXY Prim Reference Point

When the rectangle is parameterized, the corner point will remain fixed. The rectangle will grow
larger or smaller as the other three points are moved.

Drawing the Viewbox

4. Create a viewbox using the tool Creates parametric viewbox lines or Creates parametric viewboxes.

Please note: Make sure that the rectangle is inside a viewbox.

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Displaying the Grid

5. Choose the tool Draws the grid corresponding to the original drawing and undoes it .
Figure 42 below shows what happens.
Grid lines are drawn along any lines that coincide with the arms of the prim. In this
case, two grid lines are drawn. The prim supports the two grid lines.

Please note: Notice that the grid lines are not permanent. If you refresh the screen by choosing
the tool Refresh graphics from the toolbar the grid lines disappear.

Figure 42 Example1: Effect of Drawing Grid

Dimensioning the Object

The rectangle is not adequately supported by the grid at the moment. Only the bottom left cor-
ner point lies at a grid intersection. Remember that the aim is to make sure that all points lie at
grid line intersections.
6. Dimension two sides of the rectangle, one vertical and one horizontal.
7. You can see how the grid develops by using the tool Draws the grid corresponding to the
original drawing and undoes it each time you create a new dimension group.
When the rectangle is adequately dimensioned, every point will lie at a grid
intersection.
If you see any error messages while you are creating the dimensioning refer to
“Parameterization Errors” on page 51.

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Example 1: Using a Prim

Figure 43 Rectangle Dimensioned for Parameterizing

Please note: There is no message to tell you that the rectangle is adequately dimensioned and
supported by the grid. It is up to you to decide for yourself. When you are satisfied
that the grid is adequate, you can go on to replace the dimensions with new
parameters.

Testing the Definition Drawing

Before specifying any new parameters, test the drawing to make sure it can be parameterized
using the tool Parameterizes the geometry then immediately undoes . If an error message appears, you
must diagnose the problem and correct it before proceeding. See “Parameterization Errors” on
page 51 for a description of some possible errors.
8. Choose the tool Parameterizes the geometry then immediately undoes .
You should not get any error message in order to be sure that you can parameterize
the drawing.

Inserting Your Own Values

9. Replace the dimension text values with your own values by clicking on a dimension
and then replace the value in the text edit field below the dashboard.

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Parameterizing the Object

10.Now choose the tool Parameterizes the geometry then immediately undoes .
The rectangle is redrawn with the points moved to represent the desired geometry. The
result is shown in Figure 44 below.
Figure 44 After Parameterization

Please note: Notice that every point has moved except for the fixed reference point. This
transformation is only temporary. If you redraw the screen, the rectangle will be
drawn in its original shape, but with the most recent set of dimension values. If the
new shape is not quite what you want, you can change the dimension texts, and
then try again.

11.When you are happy with the result you can make the transformation permanent
using the tool Parameterizes the geometry .

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Example 2: Using Baselines

Example 2: Using Baselines

In this example, you will parameterize the rectangle you created in the last example again. This
time the reference point is fixed by a pair of intersecting static baselines rather than a prim. If an
error message appears during this example, refer to “Parameterization Errors” on page 51.
1. Draw a rectangle with center lines.

Creating a reference point

2. Add two baselines, line style Static Base Line, line type LBL, which intersect at the center
of the rectangle by choosing the tool Creates static base lines . Use the end points of the
center lines as points for the base lines.
Figure 45 Example2: Rectangle with Intersecting Baselines

The intersection of the baselines is the reference point. This does not coincide with a
point on the object geometry. This position is used to calculate how far to move the
other points during parameterization.

Please note: Notice that the ends of the baselines extend beyond the rectangle. This is
important. Never draw a static baseline that ends on an existing line. If you do so,
the line will be fixed in its present position and this may create problems when you
try to parameterize the drawing.

3. Choose the tool Parametric Layers.

4. Switch on the option Baseline and click left on the button Hide.
5. Now you can delete the centerlines easily.
6. Switch on the baselines by clicking left on the button View.

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Getting Started

Drawing the Viewbox

7. Create a viewbox using the tool Creates parametric viewbox lines or Creates parametric viewboxes.

Displaying the Grid

8. Choose the tool Draws the grid corresponding to the original drawing and undoes it .
You can see two STK type grid lines, one horizontal and one vertical. However, there
are in fact six grid lines. Each baseline supports three grid lines: one along its length,
and two at the ends of the line, perpendicular to it.

Please note: Notice that the grid lines are not permanent. If you refresh the screen by choosing
the tool Refresh graphics from the toolbar the grid lines disappear.

Changing the grid tolerance

Grid lines are drawn using a tolerance which is automatically set to 0.1 mm. Since the grid lines
at the ends of the static baselines are only 0.1 mm long it is very difficult to see them. You can
see them more clearly by changing the grid tolerance.
9. Open the dialog Parametric Switches by choosing the tool Displays the current settings of the
parametrics system.
10.Increase the Grid Tolerance by typing 3.
11.Choose the button Apply.
12.Choose the tool Draws the grid corresponding to the original drawing and undoes it .
The result is shown in Figure 46. You can clearly see six grid lines now.

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Example 2: Using Baselines

Figure 46 Effect of Changing the Grid Tolerance

Please note: Normally, you should never change the grid tolerance setting. If you do, you may
find that grid lines are being drawn through the wrong points, and that your
drawing will not parameterize.
Changing the grid tolerance is used here because it helps to illustrate how grid
lines are built up.
Do not forget to return the grid tolerance to its normal setting.

Dimensioning the Object

13.Now dimension the rectangle using chain dimensioning.

Please note: Note that it is essential to use chain dimensioning as other dimensioning methods
such as datum dimensioning do not recognize the center support provided by the
horizontal grid line (see ”Dimensioning”, “Center Support” on page 32).

14.Choose the tool Draws the grid corresponding to the original drawing and undoes it to display
the grid after every new dimensioning group. Each new dimensioning group creates
new grid lines, which in turn support more grid lines.

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Getting Started

Figure 47 Fully Dimensioned Drawing

Every point in the rectangle now lies at a grid line intersection. The next step is to test
your drawing.

Testing the Drawing

15.Choose the tool Parameterizes the geometry then immediately undoes .

There is a brief delay and then each part of the drawing is highlighted on the screen as
it is processed. Do not proceed unless the drawing is tested successfully with no error
messages. If an error message appears, you must diagnose the problem and correct it
before proceeding. See “Parameterization Errors” on page 51 for a description of some
possible errors.

Inserting Your Own Values

When you have successfully tested the drawing:

16.Replace the dimension values with some of your own.
If you choose values that are too large, the rectangle may exceed the height or width of
the maximum drawing area. It this happens, you will see a warning message.

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Example 2: Using Baselines

Parameterizing the Object

17.Choose the tool Parameterizes the geometry then immediately undoes .

The rectangle transforms according to the dimension values you have specified.
Figure 48 shows the result.
Figure 48 Result of Parameterizing

Remember that the reference point is the center of the rectangle, where the baselines
cross. Every point has been moved, but the center of the rectangle remains in the
same position on the sheet.
18.At this stage there are two things you can do.
a. Permanent parameterization
If you are happy with the result you can make the transformation permanent using
the tool Parameterizes the geometry .
This permanently transforms the geometry, and you can then save the sheet.
b. Restoring the original geometry
If you wish to continue parameterizing the rectangle, refresh the screen and the
original rectangle will be restored. The dimension values are always the last set of
values that you supplied.

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Getting Started

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SIMPLE PARAMETERIZATION EXAMPLES

This chapter contains three worked examples. Each example illustrates the use of a different
kind of dimension, chain, radial and angular.
Before working through the examples you should read the section on ”Getting Started”, “Exam-
ining the Parametric Grid” on page 48 explaining how to examine the grid. This introduces a
very useful diagnostic routine you can use to find out what is wrong with a drawing that has pro-
duced an error message.

• Example One ........................................................................... 64

• Example Two ........................................................................... 68

• Example Three......................................................................... 71

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Simple Parameterization Examples

Example One

Draw the component shown in Figure 49. Do not dimension the drawing yet. Draw the vertical
dashed line using any suitable line type, such as L1 or L6.
Figure 49 Component to be Drawn

Add the intersecting baselines. Notice that the horizontal baseline lies along the line of symme-
try. As you will see in a moment, this enables three chain dimensions to be supported. Use the
tool Draws the grid corresponding to the original drawing and undoes it to look at the grid. At this stage,
grid lines are drawn only along the baselines. You will build up the grid by dimensioning the
points in the object.
Figure 50 Displaying the Grid

What would happen if you tried to parameterize the drawing at this stage? Try it for yourself.
Refresh the screen using Refresh Graphics from the toolbar and then select the tool Parameterizes
the geometry then immediately undoes . You will find that the error message Point not dimen-
sioned is written on the sheet beside every point that is not at a grid intersection. Remove all
the error messages with Refresh Graphics .

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Example One

Dimensioning the Object

Dimension the component as shown in Figure 49, “Component to be Drawn” on page 64, using
chain dimensions for the diameters. Add the dimension groups in the order indicated below.

First stage: Add the diameter dimension shown in Figure 51. This is supported by the horizon-
tal baseline, because the baseline passes through its center. It is essential that you use chain
and not datum or coordinate dimensioning for the diameter dimensions so that they can pick up
the center support from the horizontal baseline.
Figure 51 Addition of First Chain Dimension

Each time you add a new dimension, use the tool Draws the grid corresponding to the original drawing and
undoes it to see how the grid is developing. At this stage, only two of the points lie at grid inter-
sections when you draw the grid.

Second stage: Add the 8.0 and 12.0 mm dimensions, as in Figure 52. You can use any dimen-
sion type, for example datum. When you draw the grid you will see that grid lines are drawn
along the leader lines of the dimensions and continue along other collinear lines.
Figure 52 Adding More Dimensions

When you display the grid, you will see that the dashed line helps to extend the grid. The grid
line drawn along the leader lines of the 8.0 mm dimension extends along the dashed line and

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Simple Parameterization Examples

through any collinear points. The dashed line enables this grid line to extend to the collinear
point on the other side of the component. Without the dashed line, you have to add a second
8.0 mm dimension.

Third stage: Add the 44.0 mm chain dimension and then the two diameter dimensions, as
shown in Figure 53. You can use any dimension type for the 44.0 mm dimension but you must
use a chain dimension for the 50.0 mm and 76.0 mm diameters. This ensures that the horizon-
tal baseline running through the center of the dimension supports the new dimensions on the
grid.
Figure 53 Fully Dimensioned Component

When you draw the grid, as in Figure 54, you will see that grid lines have been added along the
angled edges of the component. These grid lines have been added automatically by the sys-
tem. The grid is now complete, and every point lies at a grid intersection.
Figure 54 Complete Parametric Grid

If you wish, you can now use the procedure on ”Getting Started”, “Building the Parametric Grid”
on page 46 to draw the grid one step at a time.

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Example One

Testing the drawing

Use the tool Parameterizes the geometry then immediately undoes to test the drawing. If there are no
problems, each part of the drawing will be redrawn as it is processed. Error messages will be
displayed at the offending points if the system cannot parameterize the drawing. You may see
one of the following messages written on the sheet near to the point that is causing the problem:
No solution possible
Point not dimensioned
If you see one of these error messages, use the tool Parameterizes the geometry then immediately undoes
(see ”Getting Started”, “Parameterizing an Object” on page 50) to investigate which dimen-
sion is causing a problem.

Parameterizing the object

Replace the dimension texts with the new values shown below in Figure 55. Leave out the DIA
text (or the diameter symbol) when you give a new value to the diameter dimensions: these
extra texts are not required to calculate the new geometry.
Figure 55 Old Component With New Parameters

Now choose the tool Parameterizes the geometry then immediately undoes . The result is shown in
Figure 56. If you are happy with the new component, parameterize it permanently using the tool
Parameterizes the geometry and then save the sheet.
Figure 56 Parameterized Component

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Simple Parameterization Examples

Example Two

This example shows how to deal with fillets for parameterization.

1. Draw the object in Figure 57 but do not dimension it yet.
Use the tool Fillet Lines from the Lines + Edit tooltray to create the fillets.

Please note: The fillets have to be changed to tangent point arcs (tool Convert the selected circular
arc into a tangent point arc in the tooltray Lines + Edit) because they are circular arcs,
which is the default for fillets.

Figure 57 Object to be Dimensioned

Dimensioning the Component

2. Add static baselines, which should intersect at the center of the object.
3. Dimension the component.
Use chain dimensions to ensure center support from the horizontal baseline.
For the circle use the tool Dimensions the diameters of circles and holes.
Instead of dimensioning the fillets individually, use an in-sheet PARFIL command to set
fillets to 8.0 mm:
4. Choose the text tool Creates free parametric command text.
Below the dashboard the text edit field opens.
5. Type the text you want to place as command on the sheet:
e.g. PARFIL 8
6. Place the text on the sheet.
7. Choose the tool Draws the grid corresponding to the original drawing and undoes it for looking at
the grid.
Every point in the drawing now lies at a grid intersection (Figure 58).

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Example Two

If you have any problems then refer to ”Getting Started”, “Example 1: Using a Prim” on
page 53 or “Appendix B Error and Warning Messages” on page 217.
Figure 58 Displaying the Grid

Notice that small grid lines are drawn over the arcs of the fillets, as shown in the
detailed illustration in Figure 59. The end points of the fillets lie at grid intersections
because the ends of the arcs intersect with the straight grid lines.
Figure 59 Detail Showing Fillet Grid Lines

Parameterizing the Component

If you have tested the drawing with the tool Parameterizes the geometry then immediately undoes and
there are no problems, you can go ahead and replace the dimension texts with new values.
8. Choose the tool Sets options for fillet behavior during parameterization for opening the dialog
Parametric Filleting (see ”Dimensioning”, “Dialog PAR VAR Setting” on page 30).
9. Set the options and values you want to use and Apply your settings.
10.Use again the tool Parameterizes the geometry then immediately undoes to parameterize the
drawing.
You can continue parameterizing the component by refreshing the screen and
replacing the dimension texts with new values.

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Simple Parameterization Examples

Dimension Format

The format of dimension text on the parameterized drawing is the same as in the original dra-
wing. For example, the affixes j, R, and DIA are retained, and the original number of decimal
places are displayed regardless of the format you gave when you supplied the new parameters.

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Example Three

Example Three

Draw the object shown in Figure 60. The angle of the notch is not important, but the notch must
be symmetrical about the horizontal center baseline. In this case the angle is 75.5 degrees. If
the notch was not symmetrical about the horizontal baseline, you would have to dimension it as
two separate angles.
Figure 60 Object With Angular Notch

Adding dimensions

Add the 50.0 mm diameter dimension and the 10.0 mm chain dimension and then draw the grid
as shown in Figure 61 using the tool Draws the grid corresponding to the original drawing and undoes it .
Figure 61 Result of drawing the grid

Figure 61 shows that the grid is still incomplete. All points must be at grid intersections. To make
the circular grid line cross the gap in the object circumference caused by the angled notch, add
a line as shown in Figure 62 across the notch (any line type will do).

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Simple Parameterization Examples

Figure 62 Adding a Line

Dimensioning the Angle

Draw the grid again and you will see that the grid line created by the diameter dimension now
runs in an uninterrupted circle around the circumference of the object. Finally, place the angled
sides of the notch on the grid by dimensioning the angle. When you display the grid with the tool
Draws the grid corresponding to the original drawing and undoes it , as in Figure 63, you will see that every
point now lies at a grid intersection.
Figure 63 Dimensioned Angle With Grid

Testing the Drawing

Test the drawing with the tool Parameterizes the geometry then immediately undoes . If there are no
errors, you can now change any of the dimensions and parameterize the object. If you change
the angle, the notch will be redrawn with the specified angle. As the original notch was symmet-
rical about the baseline, the new notch will also be symmetrical. Try it for yourself. When you

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Example Three

change the text of an angle dimension, it does not matter if you miss out the degree sign: Para-
metric Design does not need it, and it will replace it for you anyway in the new dimension.

Examining the Grid

If you wish, draw the grid one step at a time to see how it was built up using the procedure in
”Getting Started”, “Examining the Parametric Grid” on page 48. Notice that the angled grid lines
drawn on the notch are supported by the vertical grid line 10 mm from the circle center.

Dimensioning an Unsymmetrical Angle

If the notch was not symmetrical about the horizontal baseline, you would have to dimension it
in a slightly different way, as shown in Figure 64. Here, the angle is treated as two separate
angles, each dimensioned from the horizontal baseline.
Figure 64 Dimensioning an Unsymmetrical Angle

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Simple Parameterization Examples

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GEOMETRIC CONSTRAINTS

This chapter shows how certain properties of object geometry, such as tangency or perpendicu-
larity, are preserved during parameterization.

• What Are Geometric Constraints? ........................................... 76

• Looking at Inferred Constraints................................................ 77

• Baselines ................................................................................. 78

• Specifying Constraints Explicitly .............................................. 80

• Example One ........................................................................... 81

• Example Two ........................................................................... 83

• Example Three......................................................................... 86

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Geometric Constraints

What Are Geometric Constraints?

Geometric constraints are automatically inferred by the Parametric Design system to ensure
that certain properties of the original geometry are preserved when you parameterize a drawing.
For example, a tangent line remains tangential and a perpendicular line remains perpendicular.
Figure 65 shows a simplified diagram of a bicycle chainset. The chainset consists of a large
sprocket, a small sprocket and a chain that fits tightly around them. The chain is constructed
from two separate line segments, each drawn tangential to the sprockets. To parameterize the
drawing, you would begin by dimensioning the diameter of each sprocket and the distance
between them. The chain is not dimensioned in any way.
Figure 65 Simplified Diagram of a Bicycle Chainset

You may want to change the size of the sprockets or the distance between them. The chain, of
course, should always remain tangential to the sprockets. Parametric Design automatically
ensures this whenever you parameterize the drawing. All you have to do is to dimension the
drawing in the usual way.

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Looking at Inferred Constraints

Looking at Inferred Constraints

If geometric constraints are applied automatically by the system, how do you know what con-
straints will be applied? The answer is to look at the current geometric constraints either with
the tool Draws baselines inferred when the baseline switch is on or the PAR GRIS BAS Bacis1 com-
mand (which is explained in the Parametrics Reference Guide, chapter “Geometric constraints“,
section “Automatically Inferred Constraints“).

Displaying Inferred, Dynamic Baselines

The tool Draws baselines inferred when the baseline switch is on draws a dynamic baseline on top of
any lines in the drawing where constraints have been automatically inferred from the geometry.
These lines are chain lines of type LBL and are placed on layer 16. The point functions at the
ends of the baselines indicate how the geometry is constrained when the drawing is parameter-
ized.
The automatically inferred baselines are drawn permanently. For parameterization these lines
can be kept (see “Faster Parameterization by Dynamic Baselines” on page 79) but you also can
delete them, see below.

Deleting Inferred, Dynamic Baselines

Dynamic baselines are drawn only to help you to understand how the drawing is constrained
during parameterization. You do not need to leave them on the sheet once you have found out
where constraints have been inferred.
For deleting inferred baselines,
1. Open the dialog Parametric Layers (see ”Layers and Parametric Switches”, “Parametric
Graphics Control” on page 111).
2. Switch on the option Inferred Baselines.
3. Click left on the button Delete.
The inferred baselines are removed immediately.

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Geometric Constraints

Baselines

Every point in a baseline has a particular function that determines the way in which the line is
constrained during parameterization.

Baseline Point Functions

The point functions shown below have special meaning in Parametric Design.
FUNV Symbol Point function

0 Static point

10 Perpendicular point

11 Intersection point

12 Tangent point

26 Circle center point

A baseline point with any of the point functions listed in the table above moves according to a
particular geometric constraint during parameterization. For example, if the end of a baseline
has point function FUNV11, that line segment remains fixed to a particular point or intersection
throughout parameterization. If a baseline segment has point function 10, the line segment will
remain perpendicular.

Static Baselines

A static baseline is a baseline with a FUNV0 point function at each end. A FUNV0 point does
not move during parameterization. Static baselines remain in the same position on the sheet
when you parameterize a drawing, regardless of how the object geometry changes.

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Baselines

Baselines and The Parametric Grid

Static baselines can be drawn anywhere within the viewbox and are used to support the para-
metric grid.
Dynamic baselines are constructed along existing lines and must be supported on the grid.

Faster Parameterization by Dynamic Baselines

Leaving any dynamic baselines created with the tool Draws baselines inferred when the baseline switch is
on in the master drawing can speed up parameterization. Parametric Design automatically
looks to see where it can infer geometric constraints before parameterizing geometry. If you use
dynamic baselines to specify explicitly any constraints that you need, you can then tell Paramet-
ric Design not to infer any constraints automatically. The system does not then spend any time
trying to infer constraints from the geometry.
You use the PAR BAS switch to switch automatic inference of geometric constraints ON and
OFF. If you want to leave baselines in the drawing, use the following procedure:
1. Create a master drawing and test it to make sure it can be parameterized.
2. Use the tool Draws baselines inferred when the baseline switch is on to add dynamic baselines
where constraints may be inferred.
3. Save the sheet.
4. Set the parametric switch PAR BAS to OFF.
You can do this interactively or using an in-sheet command.
5. Parameterize the drawing.

The PAR BAS Switch

The PAR BAS switch controls whether geometric constraints are inferred automatically or not.
When PAR BAS is OFF, constraints are not automatically inferred, so you need to specify them
explicitly. When PAR BAS is ON, constraints are inferred automatically from the object geome-
try.
You can change the current PAR BAS setting by giving an in-sheet PAR BAS ON or OFF com-
mand or in the appropriate dialog, see ”Layers and Parametric Switches”, “Parametric Switches
and Command Texts” on page 112.
PAR BAS is ON by default. For more information on the PAR BAS switch refer to the MEDUSA
Parametric Design Reference Guide.

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Geometric Constraints

Specifying Constraints Explicitly

Normally Parametric Design calculates for itself which geometric properties need to be main-
tained. When the drawing is parameterized, lines such as tangents and perpendiculars are
adjusted automatically. Most of the time, therefore, geometric constraints are deduced for you.
If you want to impose additional limitations on geometry you can also add dynamic baselines to
a drawing manually. This may be necessary,
• when insufficient baselines are inferred automatically
• when you want to constrain a component or mechanism in a particular way, for
example to force one end to remain static with the other end linked to a point which
moves.
To create a dynamic baseline:
1. Choose the tool Creates static baselines .
The dialog Parametric Point Function opens. All entries are deactivated until you have
placed the first point of the line.
2. Place the first point of the baseline.
The point functions in the dialog are activated.
Figure 66 Dialog Parametric Point Function, activated

3. Choose a point function for the first point of the line.

If you choose no point function, Static, FUNV 0 is used, which is the default.
Consider that the point function of the first point is not displayed on the sheet until you
placed the second point of the baseline. For all further points the point function is
drawn immediately.
4. Place the second point of the line.
5. Choose a point function for the second point of the line.
6. Go on like this for further points of the dynamic baseline.
7. If you want to finish the line choose New line or Exit tool from the popup menu.
If you create any dynamic baselines manually, leave them in the master drawing when you
parameterize it.

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Example One

Example One

This example shows how you can use tool Draws baselines inferred when the baseline switch is on to
display constraints inferred by the system. These are constraints of intersection, perpendicular-
ity, and tangency.

Drawing the Object

Draw and dimension the object in Figure 67. Make sure that the angled line segment and the
horizontal line segment are both tangential to the arc.
Figure 67 Object to be Parameterized

Looking at Constraints

Now draw the parametric grid using the tool Draws the grid corresponding to the original drawing and undoes
it . This example might look quite ordinary but something special has happened. Refresh the
screen with Refresh Graphics and then use the tool Draws baselines inferred when the baseline switch is on
to see which line segments are being constrained automatically.
Figure 68 Inferred Baselines

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Geometric Constraints

Figure 68 gives you an idea of what you will see. The outline of the component has been drawn
using a dashed line so that you can see the dynamic baselines more clearly and the point func-
tions have been labelled. Two LBL lines are drawn over the line segments that will be con-
strained automatically when you parameterize the component. The end of each line is marked
with a special point function. The end with the FUNV12 point function is a tangent point, and the
ends with FUNV11 point functions are intersection points. The end with a FUNV10 point func-
tion will remain perpendicular to the vertical edge of the component.

Taking a Closer Look

You can see the dynamic baselines and their point functions more clearly if you clear the screen
and then draw just the layer 16 (Parametrics - automatically generated baselines) containing the baselines:
The important feature of this example is that you can change the arc radius or the horizontal
dimension, but the angled straight segment will remain tangential to the arc, and the horizontal
line will remain perpendicular to the intersection point. If you wish, you can now delete the
dynamic baselines.

Parameterizing the Object

Test the drawing with the tool Parameterizes the geometry then immediately undoes . If there are no
problems, parameterize it with a new set of parameters. Figure 69 shows the drawing after it
has been parameterized with the arc radius set to 12.5 mm.
Figure 69 Object with New Set of Dimensions

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Example Two

Example Two

This example shows how the system infers tangency constraints on a component.

Drawing the Object

Draw the component shown in Figure 70 in a horizontal position and then rotate it. Add static
baselines but do not dimension the component yet. All straight segments are tangents.
Figure 70 Object to be Parameterized

Dimensioning the Object

To dimension the object, first add the 44 mm chain dimension. This is symmetrical about one of
the baselines. The center of each small arc lies now lies at a grid intersection. Add the two
diameter dimensions and then dimension the arcs. When the drawing is fully dimensioned,
draw the parametric grid. The result is shown in Figure 71.
If you look closely at the drawing you will see that four grid lines have been added automatically
where there is no dimensioning. These are the four straight segments forming the outline of the
component. Each straight segment is tangential to an arc at both ends.

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Geometric Constraints

Figure 71 Displaying the grid

Looking at Constraints

When you run the tool Draws baselines inferred when the baseline switch is on , a dynamic baseline is
drawn over each part of the drawing that is to be constrained automatically by the system. The
added lines are shown in Figure 72. The dimensioning and static baselines have been removed
here and the outline of the component is shown as a dashed line so that you can see the
dynamic baselines more clearly.
Figure 72 Inferred Baselines

You can see four LBL lines have been drawn over those line segments constrained to remain
tangential during parameterization. The end of each line has a FUNV12 point function. When
this object is parameterized, the four line segments indicated by the dynamic baselines will
always remain tangential to the arcs.

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Example Two

Taking a Closer Look

You can see the dynamic baselines and their point functions more clearly if you clear the screen
and then draw just the layer 16 (Parametrics - automatically generated baselines) containing the baselines:

Parameterizing the Object

Use the tool Parameterizes the geometry then immediately undoes to test the drawing then change
some of the dimensions and parameterize the object. Note how the straight line segments
always remain tangential to the arcs.

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Geometric Constraints

Example Three

This example shows how the system infers intersection and tangency constraints on a compo-
nent.

Drawing the Object

Draw the component in Figure 73 in a horizontal position using the hints given below. Add the
static baselines but not the dimensions, and then rotate the component through an arbitrary
angle to avoid restrictions imposed by special cases.
Figure 73 Object to be Parameterized

Add two supporting lines to place the fillet arcs on the grid, as shown in Figure 74. These can be
any line type. When you have done this, draw the grid, as shown in Figure 75.
Figure 74 Detail of Fillet Construction from Component in Figure 73

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Example Three

Figure 75 Displaying the grid

Dimensioning the Component

First step: Add the 35.0 mm radial dimension then draw the grid. Notice how grid lines extend
along the arc to the tangent points. Next dimension the distance between the reference point
and the intersection point between the baseline and the base of the component (64.0 mm). Add
the two parallel chain dimensions across the base of the component. Notice that the 25.0 mm
dimension places the fillet tangent points on the grid.

Second step: Next add the 12.0 mm parallel chain dimension. This creates three extra grid
lines, not just one. These extra grid lines linking the fillet tangent points to tangent points on the
large arc have been inferred automatically.

Adding an in-sheet Command

Finally, place an in-sheet PAR FIL command inside the viewbox to set the fillet dimension val-
ues to 5 mm. The grid for the fully dimensioned component is shown in Figure 76 and a more
detailed view of the fillets is shown in Figure 77.
Figure 76 Fully Dimensioned Drawing With Grid

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Geometric Constraints

Figure 77 Fillet Detail from Figure 76

Looking at Constraints

Now you can use the tool Draws baselines inferred when the baseline switch is on to see what infer-
ences have been made from the object geometry. Figure 78 shows where dynamic baselines
are drawn. In this example, two baselines are added. Both have an intersection point function
(FUNV11) at one end and a tangent point function (FUNV12) at the other. When you parameter-
ize the drawing, these line segments may move, but the FUNV12 points will remain tangential to
the large arc, and the FUNV11 points will be tied to intersection point on the base of the compo-
nent.
Figure 78 Dynamic Baselines

Taking a Closer Look

You can see the dynamic baselines and their point functions more clearly if you clear the screen
and then draw just the layer 16 (Parametrics - automatically generated baselines) containing the baselines:

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Example Three

Parameterizing the Object

Delete the dynamic baselines if you wish, then test the drawing with the tool Parameterizes the geom-
etry then immediately undoes . Now experiment by changing the dimensions and parameterizing
the object. Figure 79 shows one possible result.
Figure 79 After Parameterization

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Geometric Constraints

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VARIABLES AND EXPRESSIONS

This chapter describes how to replace values in dimensions with variable parameters.
MEDUSA Parametric Design calculates the value of any variables during parameterization and
changes the object dimensions to reflect the new values.

• Values in Dimensions............................................................... 92

• Variables .................................................................................. 94

• Assigning Values to Variables Using in-sheet commands ....... 96

• Assigning Values to LCIS Variables ......................................... 98

• Administration, Loading and Updating Variables ................... 100

• Errors While Using Variables ................................................. 104

• Expressions ........................................................................... 105

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Variables and Expressions

Values in Dimensions

So far, whenever you have prepared a drawing for a parametric operation, you have changed its
dimensions from one set of numbers to another. One of the most useful features of Parametric
Design is that you can use variables such as WIDTH or DIAM and expressions instead of partic-
ular values.

Variables

Figure 80 shows a drawing of a joist section. Using variables to define the dimensions enables
you to scale the section to whatever size you require. Each time you parameterize the drawing,
you can give the variables a different value.
Figure 80 Use of Variables in Joist Definition

Figure 81 shows some joist sections which are the result of parameterizing the drawing shown
in Figure 80. A LET command was used to give different values to the following variables each
time:
• D (section depth)
• B (section width)

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Values in Dimensions

• S (web thickness)
• T (flange thickness)
• R (root radius)
• V (toe radius)
Figure 81 Result of Changing Joist Dimension Variables

Expressions

Expressions are particularly useful when you want to scale a component. Using expressions
you can specify relationships between dimensions within the same drawing. For example, if the
width of a component always needs to be half of the length, you could replace the length dimen-
sion value with the variable LENGTH and the width dimension value with the expression
(LENGTH/2).
In Figure 80, “Use of Variables in Joist Definition” on page 92, the expression (B + S) / 2 is
used to locate the mid-flange position. Whenever this drawing is parameterized, the mid-flange
dimension value is derived by adding the current values for the width of the section (B) and the
web thickness (S) and dividing the result by two.

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Variables and Expressions

Variables

When you have dimensioned your drawing in the usual way and checked that the drawing can
be parameterized you can replace any of the dimension text with variable names.

Replacing Dimension Texts

It is not necessary to change all dimensions to variables. You can leave some as numerical val-
ues. For example, if a number of components differ only in diameter, change the dimension text
for the diameter to the variable name DIAM, and leave all other dimensions as numbers.

Rules for Creating Variable Names

A variable name must meet the following requirements:

• The maximum length is 6 characters.
• The first character must be a letter of the alphabet.
• The name must consist of the letters A- Z, the numbers 0-9 or the characters comma (
,) # or %. Spaces are not allowed.
• Letters can be uppercase or lowercase characters. FILLET is identical to fillet and
Fillet.
Some typical variable names are: A, B1, width, LIN6, dia, fillet, RAD.

After Parameterization

After parameterization all parametric dimension variable names and expressions are evaluated
and replaced by their numeric values. By selecting the Refresh Graphics tool , you can restore
the original shape of the drawing and dimension variable names and expressions are also
restored. If you do not cancel the parameterization, these variables and expressions are perma-
nently changed into values.

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Variables

Defining Radius Dimensions

If you use a variable to define a radius dimension, do not use variable names that begin with the
letter R and are followed by a number, for example, R15. If you do, Parametric Design assumes
this is a radial dimension with prefix text and interprets these ambiguous texts as values during
parameterization. When this happens, the following warning message is displayed on the sheet:
Warning - ambiguous dimension texts interpreted as values

Example

Draw and dimension a rectangle, as in Figure 82. The size of the rectangle is not important.
Make sure the drawing can be parameterized by testing it with the tool Parameterizes the geometry
then immediately undoes .
Figure 82 Dimensioned Drawing

Now replace the dimension texts with variables:

1. Make the dimension text current.
2. Place the variable name into the text buffer, for example, short.
In Figure 83 the dimension texts have been replaced by the variable names long and short.
Figure 83 Replacing Dimension Texts With Variables

Before you can parameterize this drawing, you must assign values to the variables long and
short. This is described in the next section.

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Variables and Expressions

Assigning Values to Variables Using in-sheet commands

There are two ways of giving MEDUSA commands:

• By typing the command at the keyboard (interactively in Bacis1 mode)
• By placing in-sheet command text on the sheet
You can use many Parametric Design commands both interactively and as in-sheet commands.
When you enter a command interactively, the command is executed immediately. In-sheet com-
mands are not executed until you run a parameterization tool.

Why Use in-sheet Commands?

The advantage of using in-sheet commands is that they are stored with the sheet, so that, for
example, special parametric switch or layer settings are always used with a particular drawing.
In-sheet commands are executed when you run a parameterization tool, before the geometry is
parameterized.
In-sheet commands only affect the viewbox in which they are placed, so other viewboxes and
other sheets are not affected. After parameterization, all settings are restored to the values held
before parameterization.
You should always aim to use in-sheet commands rather than interactive commands when
working with Parametric Design.

Creating in-sheet Commands

Use the following procedure to create an in-sheet command:

1. Choose the tool Creates free parametric command text .
Below the dashboard the text edit field opens.
2. Type the text you want to place as command on the sheet, for example:
LET long = 80
3. Position the new text by probing on the sheet.
4. Type further texts and place them.
Figure 84 below shows how in-sheet commands LET and DEF are used to assign values to the
dimension variables long and short.

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Assigning Values to Variables Using in-sheet commands

Figure 84 Example of In-sheet Commands

When you parameterize the drawing using the tool Parameterizes the geometry then immediately undoes
, the rectangle is redrawn using the dimensions you have specified in the in-sheet command
texts.

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Variables and Expressions

Assigning Values to LCIS Variables

Please note: LCIS variables are available for the current MEDUSA session only. In the next
session you have to define them new. For saving LCIS variables use the Bacis1
mode.

Creating a LCIS Variable

1. For creating a LCIS a variable choose the tool Creates user LCIS variables.
The following dialog opens.
Figure 85 Dialog for Creating LCIS Variables

2. Type in the Name and the Value for the variable.

Please note: Value can be either an integer or a floating point value. Expressions are not
allowed.

3. Apply the variable.

The dialog remains open for defining further variables.
4. If you have defined your last variable, choose OK to apply the variable and close the
dialog.

Query and Modify LCIS Variables

You can query any LCIS variable. Additionally to the variables you defined, many system vari-
ables can be queried.

Please note: Changing system variables is not recommended.

For querying or modifying LCIS variables choose the tool Query and modify LCIS variables.
The following dialog opens.

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Assigning Values to LCIS Variables

Figure 86 Dialog for Query LCIS Variables

Filter
allows to pre-define the variables which are listed. You can type in any letter, number
or special character available on your keyboard. If a variable name contains the Filter
string than it is listed after choosing the button Filter. Wildcards like question mark (?) or
asterisk (*) are not allowed. Same is with carriage return and space.
User, Protected, System
allows to pre-define the variables which are listed. You can specify user defined,
protected and system variables.
Value
On the right hand side of Value there is the edit field displaying the value for the
currently selected variable.
OK, Apply
confirms the current values for the variables and now they are used in MEDUSA.
Additionally OK closes the dialog. If you choose Apply the dialog remains open.
Filter
This button updates the display of the variable list according to the defined pre-
definitions.

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Variables and Expressions

Administration, Loading and Updating Variables

Variables used inside a parametric sheet and its values can be saved with the sheet. For this
two tools are provided:
• Administrating parametric variables scans the sheet for existing variables and values.
Administration includes editing variables, defining title, picture and macro and saving
all this information within the sheet (see ”Administration”).
• Loading and updating variables allows to change variable values and save them within
the sheet (see “Loading and Updating” on page 102).

Please note: The administration of variables can be done in Administration Mode only.

Administration

The tool Administrate parametric variables reads all the dimension variables available inside the
viewboxes of the current sheet. If there are none, an error message is given. Also the associ-
ated default values for the variables are read. If default values cannot be found, the appropriate
variable will be initialized with the standard value. All information is displayed inside a dialog.
Figure 87 Dialog Administrate parametric variables

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Administration, Loading and Updating Variables

The Administrate parametric variables dialog contains the following parameters:

Title is the name of the variable table and it may not be empty because it is used for
identification when using the Load and Update dialog, see “Loading and Updating” on
page 102. If the title is not defined the Load and Update dialog will not work.
Picture gives path and file name (*.gif) of the picture, which will be displayed in the Load and
Update dialog.
Parameterize
If this option is switched on, pressing the button OK parameterizes the drawing.
Macro gives path and file name of the macro, which will be started after the parametrization
using the OK button.
The table contains the following columns:
Variables contains the names of the variables (this column is not editable).
Information
contains the describing text for the variable.
Values contains the value of the variable.
Position contains the position of the variable in the dialog. The column Position is empty by
default and the Administrator has to define positions. If no position is defined, the
succession of variables is random.
The following buttons are provided:
OK saves all variables with its information, values and positions into the sheet,
parameterizes the sheet (if the option Parameterize is on) and starts the macro (if defined
in Macro text field). The Administrate parametric variables dialog will be closed.
If the option Parameterize is on, choose Undo from the toolbar, if you want to test other
settings. Consider that after parameterization you cannot open the Administrate parametric
variables dialog until you have undone parameterization.
If you defined a Macro you have to press Undo twice.
Save saves all variables with its information, values and positions into the sheet.
Consider that this button does not save the sheet. If you close the sheet without saving
it, the settings will be lost.
Add adds a new parametric variable. It is used for variables, which could not be read from
the sheet.
Figure 88 Add new parametric variable

After defining the variable name and setting the option (if required) press Add.
The value will be defined directly inside the list of variables.

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Variables and Expressions

If the option Allow string as value? was switched on, you can define expressions like this:
length/2+val2, otherwise you can define integer or real values only.
Delete delete a new parametric variable. Variables read from the sheet cannot be deleted.
Cancel close the dialog without applying any dialog entries. Change you have made will be
lost.
Having made all settings for the parametric variables of a sheet, choose Save the current sheet in
the toolbar to save the table with the sheet.

Loading and Updating

Any user can display and update the values of parametric variables saved within a sheet.
Updated values can also be saved within the sheet.
Choose the tool Load and update parametric variables to open the following dialog.
Figure 89 Dialog Load and Update parametric variables

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Administration, Loading and Updating Variables

On top of the dialog the title and the picture (if defined) are given as defined by the Administra-
tor. Below this the list of variables is given with its information labels and values as saved within
the sheet.
You can edit variable values and save them in the sheet using the Save button.
For parameterization use the OK button. Consider that parameterization includes running the
macro, if defined by the Administrator. The Load parametric variables dialog will be closed.
Choose Undo from the toolbar, if you want to test other settings. Consider that after parame-
terization you cannot open the Load parametric variables dialog until you have undone parameteriza-
tion. If also a macro has been run you have to press Undo twice.

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Variables and Expressions

Errors While Using Variables

An error message appears if you try to use a variable name without first having given it a value.
For example, if your drawing contains the variable WIDTH and you have not executed a com-
mand to set its value, such as LET WIDTH = 170, then the following error message is written
close to the appropriate dimension line when you try to parameterize the drawing:
Undefined variable

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Expressions

Expressions

You can also turn dimension values into expressions. Instead of replacing dimension texts with
variable names such as DIAM or LENGTH, replace them with expressions containing variables,
for example:
A+B*2+27
(3.14*(RADIUS**2))
You must give the variable names A, B, and RADIUS values using one of the methods
described on “Rules for Creating Variable Names” on page 94. Expressions are particularly
useful for specifying relationships between different dimensions in the same drawing.

The DEF Command

You create expressions using either LET or DEF. Use DEF to define an unevaluated expres-
sion. DEF is useful for defining expressions containing variables that are constantly changing.
For example, the expression (WIDTH/LENGTH)**2 contains variables which can change each
time the drawing is parameterized. To obtain the correct value, this expression must be evalu-
ated each time the object is parameterized, using the current values of the variables WIDTH
and LENGTH. Use single or double quotation marks to enclose an expression, for example:
DEF WIDTH = 'LENGTH/2'
As with LET, you can use DEF both interactively and as an in-sheet command. Refer to the
MEDUSA Bacis1 Design Commands Guide for more information about LET and DEF.

Example

Using the drawing from the last example, replace the first LET command with a DEF command
that defines short as an expression, as shown in Figure 90. This command sets the value of
the variable short to one fifth of the value of the variable long.
Figure 90 In-sheet DEF Command

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Variables and Expressions

Parameterize your drawing using different values for long and short. You will see that replac-
ing dimension text with expressions provides a useful mechanism for defining relationships
between different dimensions.

Arithmetic Operators

You can use the following arithmetic operators in expressions:

+ Add
- Subtract
/ Divide
* Multiply
** Raise to the power of
Use rounded brackets to enclose those parts of the expression to be calculated first. Brackets
can be nested to any level. On all MEDUSA platforms, expressions can be enclosed in round
brackets ((...)) or angle brackets (<... >). Note, however, that you cannot use angle brackets
within expressions. For example:
Valid expressions
<LEN + 10>
<A*(B-4)>
(A*(B-4))
Invalid expressions
<A*<B-4>>
(A*<B-4>)

Logical Operators

You can also use a variety of logical operators to define conditions for parameterization. Details
of these operators can be found in the MEDUSA Bacis1 Guide. The MEDUSA Parametric
Design Reference Guide describes how you can use logical operators in the Parametric Design
system.

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LAYERS AND PARAMETRIC SWITCHES

This chapter describes how you can change the way drawings are parameterized by changing
parametric switches and layer properties. Layers have properties that affect whether or not they
are drawn and whether elements on them can be changed.

• How Layers Are Used ............................................................ 108

• Changing Layer Properties .................................................... 110

• Parametric Graphics Control...................................................111

• Parametric Switches and Command Texts ............................ 112

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How Layers Are Used

Layers have properties that affect whether or not they are drawn and whether elements on them
can be changed. There are two properties that are used only in Parametric Design, transform-
able (TRN/UNTRN) and deleteable (UNDEL/DEL).

Layer Defaults

Elements created by Parametric Design are placed on the following layers by default:
Layer Element type
4 Dimensioning, baselines
13 Attachment points, instance groups
14 In-sheet command text, table elements
15 Parametric groups
16 Automatically inferred baselines
17 Special grid lines created by PAR GRIS COL, CIR, and TAN
28 Viewbox lines
56 Orthogonal 3D view prims
99 Error messages, grid lines (type STK)

If you wish, you can change these layer defaults using the PAR DDL Bacis1 command. PAR
DDL is not covered in this book but it is described in the MEDUSA Parametric Design Refer-
ence Guide, chapter “Switches and Layers“, section “Changing Layer Properties“.

Layer Properties

There are 1024 layers, numbered from 0 through 1023. Each of these layers has five properties
which are listed below. The default setting for all layers is indicated using bold text:
• Transformable or Untransformable (TRN/UNTRN)
• Deletable or Undeletable (DEL/UNDEL)
• Visible or Invisible (VIS/INVIS)
• Hittable or Unhittable (HIT/UNHIT)
• Protected or Unprotected (PRO/UNPRO)

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You can use the Q LIS Bacis1 command to query the current layer properties.

Transformable/Untransformable (TRN/UNTRN)

Default: Transformable (TRN).

Elements on transformable layers can be parameterized, providing that the layers are also hitta-
ble (HIT) and unprotected (UNPRO). If you place an element on a layer that is untransformable
(UNTRN), it may not be parameterized, but it is used to create the parametric grid.

Deletable/Undeletable (DEL/UNDEL)

Default: Undeletable (UNDEL).

Elements on deletable layers (DEL) are deleted when the drawing is parameterized. This is
useful for example, for deleting dimensioning and in-sheet commands from the final parameter-
ized drawing.

Visible/Invisible (VIS/INVIS)

Default: Visible (VIS).

Elements on visible (VIS) layers are displayed on the screen. If you make a layer invisible
(INVIS) then all elements on that layer are parameterized normally, but they are not redrawn
afterwards.

Hittable/Unhittable (HIT/UNHIT)

Default: Hittable (HIT).

If you place an element on a layer that is unhittable (UNHIT), it is completely ignored by the
Parametric Design system. You can not locate it with probes or make it current. It is not used to
build the grid, and it is not transformed when the rest of the drawing is parameterized.

Protected/Unprotected (PRO/UNPRO)

Default: Unprotected (UNPRO).

Elements on unprotected layers can be parameterized or deleted. Elements on protected layers
(PRO) are not parameterized, but they may be used to create the parametric grid.

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Changing Layer Properties

Most layer properties like visible and hittable can be changed in the graphical user interface
using the menu Layers -> Layer Manager. Details on this are given in the MEDUSA Drafting Guide,
chapter “Layers“.
If you want to change the properties transformable and deleteable, use the Bacis1 LAY com-
mand.

The LAY Command

You can use the LAY command both interactively and as an in-sheet command. It is advisable
to use in-sheet commands to change layer settings rather than entering the commands interac-
tively. This is because in-sheet commands are stored with the sheet, so that special layer set-
tings are always used with a particular drawing and do not affect any other sheets. Refer back
to ”Variables and Expressions”, “Creating in-sheet Commands” on page 96 for information
about creating in-sheet commands.

How to Use Layer Commands

You can use layer commands to do the following:

• Delete parts of the drawing during parameterization. For example, you may not want
dimensioning, in-sheet commands or tables to appear in the final drawing.
• Prevent elements being parameterized, for example, table elements. You will see an
example of this when you work through the next chapter.
You can do several things with a single layer command. For example, the following command
when placed on a sheet prevents layers 4, 13 and 14 being transformed during parameteriza-
tion and also deletes all elements on those layers from the final parameterized drawing:
LAY 4 13 14 UNTRN DEL

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Parametric Graphics Control

Parametric Graphics Control

This tool is used to view, hide or delete parametric elements. For opening the dialog Parametric
choose the tool Control visibility of parametric elements
Graphics Control from the tooltray Parametric.
Figure 91 Dialog Parametric Graphics Control

In the bottom of this dialog the buttons Delete, View, Hide and View all work on the elements defined
by the selected option. Elements of the selected option are displayed highlighted in the drawing
area. If there are no elements for the chosen option, the buttons are deactivated.
The buttons delete, hide or view the following elements:
Dimensions
Instance named groups
Group Lines
Option for elements of style Parametric Group Line created, for example, with the tool
Creates parametric group lines (see ”Parametric Groups”, “Creating a Parametric Group”
on page 162).
Viewboxes
DXY prims
Baseline
Option for elements of style Static Base Line created, for example, with the tool Creates static
base lines (see ”Getting Started”, “Creating a Reference Point” on page 43).
In Sheet Command
Inferred Baseline
Option for automatically created baselines which can be drawn with the tool Draws
baselines inferred when the baseline switch is on, see section ”Getting Started”, “Building the
Parametric Grid” on page 46.
3D view prims
Option for 3D prims which can be used for parameterization, see ”Appendix A
Parametric Design Element Defaults”, “Basic Parametric Elements” on page 214.
Attachment Points
Table Element
Grid lines
Errors
Option for error message texts.

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Parametric Switches and Command Texts

Parametric switches affect, for example, how grid lines are generated. You can define them glo-
bally for the MEDUSA session and you can create them as in-sheet command texts. The follow-
ing figure shows the toolset for setting parametric switches and command texts:
Figure 92 Toolset for Switches

The tools from left to right are:

Displays the current settings of the parametrics system
provides the switches which affect the operation of the parametric design system and
the Grid Tolerance globally for the MEDUSA session.
Figure 93 Dialog Parametric Switches

The following table gives a short description on each switch:

Switch Description
PAR BAS controls whether geometric constraints are inferred automatically or not.
When PAR BAS is ON (default), the system uses the potential grid lines to
infer geometric constraints automatically. When PAR BAS is OFF, constraints
are not automatically inferred, so you need to specify them explicitly.
PAR COL controls the generation of grid lines along non-overlapping collinear line
segments. When PAR COL is ON, grid lines extend across non-overlapping
collinear line segments. Default setting is OFF.

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Switch Description
PAR CIR controls the generation of circular grid lines for all arcs. When the PAR CIR
switch is ON, complete circular grid lines are generated from arcs of circles in
the viewbox. Default setting is OFF.
PAR LIM makes grid lines either limited (ON, default) or unlimited (OFF). Unlimited grid
lines are limited only by the edges of the parametric viewbox.
PAR MOV When the PAR MOV switch is OFF, dimension texts are replaced by new
parameters but the original geometry is not transformed. If PAR MOV is OFF
when loading parametric symbols, the symbol will be loaded at the same
position it had in the definition sheet. Default setting is ON.
PAR PRE When the PAR PRE switch is OFF, dimensioning within parametric groups is
ignored and points move with the group. Default setting is ON.
PAR TAN When the PAR TAN switch is turned OFF, the tangent lines of tangent point
arcs are not used to create the potential grid. The default setting for PAR TAN
is ON because the tangential grid lines are almost always needed to place
the tangent points of tangent point arcs at grid intersections.
PAR TEX When PAR TEX is OFF, geometry is transformed according to the new
parameters in the dimension groups but the dimension texts display their
original values after parameterization. Default setting is ON.
PAR UND When PAR UND is ON (default), the original object definition is undrawn
when you parameterize. This is done before drawing the new object, so the
old component disappears before the new one is drawn. This switch is used
when simulating mechanical movement.
Creates parametric command text
opens the dialog for placing the switches as in-sheet commands.
Figure 94 Dialog Command Options

From left to right the succession of switches is the same as it is in the dialog Parametric
Switches from top to bottom. In the upper row you find the buttons for turning on
switches and in the bottom row you turn switches off. Selecting one of the icons
attaches the appropriate text to the cursor for placing it in the sheet.
Creates free parametric command text
is the same as Creates parametric command text
but the text to place is free and not pre-
defined. This tool works in the same way as other text tools from Text + Dimension

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tooltray. For an example of using this tool see ”Variables and Expressions”, “Creating
in-sheet Commands” on page 96.
The following sub-sections explain some of the switches more detailed.

The PAR COL switch

This switch controls the generation of grid lines along non-overlapping collinear line segments.
When PAR COL is ON, grid lines extend across non-overlapping collinear line segments when
you display the grid. You can change the setting for PAR COL by creating in-sheet command
text and placing it inside the same viewbox as your drawing. The default setting for PAR COL is
OFF.
Figure 95 Collinear Points With PAR COL OFF

The object in Figure 95 has several non-overlapping collinear lines. With PAR COL set to OFF,
the grid lines extend only along the dimensioned line segments. To make the grid line extend to
the other collinear lines you would have to dimension each one individually.
Figure 96 Collinear Points With PAR COL ON

Figure 96 above shows the grid with PAR COL set to ON. The grid lines span the gaps between
any points in the viewbox that are collinear. This gives a complete grid without having to add fur-
ther dimensions.

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The PAR BAS switch

The PAR BAS switch controls whether geometric constraints are inferred automatically. When
PAR BAS is OFF, constraints are not automatically inferred, so you need to specify them explic-
itly. When PAR BAS is ON, constraints are inferred automatically from the object geometry.
Refer to ”Geometric Constraints”, “The PAR BAS Switch” on page 79 for information about how
to use PAR BAS to speed up parameterization.

The PAR CIR switch

This switch controls the generation of circular grid lines for all arcs. When the PAR CIR switch is
ON, complete circular grid lines are generated from arcs of circles in the viewbox when you dis-
play the grid. The default setting for PAR CIR is OFF.
The object in Figure 97 is dimensioned radially. When you draw the grid with PAR CIR set to
OFF, as shown, only the dimensioned arc is supported.
Figure 97 Effect of PAR CIR OFF

Figure 98 shows what happens when the grid is drawn after an in-sheet PAR CIR ON command
has been added. A complete circular grid line is generated supporting the whole circle, and not
just the dimensioned arc.
Figure 98 Effect of PAR CIR ON

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The PAR UND switch

This switch is used when simulating mechanical movement.

When PAR UND is ON, the original object definition is undrawn when you parameterize. This is
done before drawing the new object, so the old component disappears before the new one is
drawn. This is the default setting.
With PAR UND set to OFF, the original definition remains visible until you refresh the screen.
When you parameterize with PAR UND OFF, you can see the parameterized and unparameter-
ized versions of the drawing simultaneously.
Figure 99 Original Geometry With New Parameters

The object shown in Figure 99 has been prepared for parameterization. The original dimension
values have been replaced with new parameters.
Figure 100 shows the result of a parameterization. Both the original and the parameterized ver-
sions of the object (complete with dimensioning) can be seen. The original object definition can
be removed by redrawing the graphical area.
Figure 100 Original and Parameterized Versions

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TABLES

This chapter shows how you can use tables to store one or more groups of values on a sheet
for subsequent during parameterization. A table is composed of a set of special elements.

• Structure of a Table ................................................................ 118

• Creating a Table..................................................................... 120

• Where to Place a Table.......................................................... 123

• Accessing Values From a Table............................................. 124

• Worked Example.................................................................... 126

• Parameterize Variant from a Table......................................... 131

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Tables

Structure of a Table

Using a table you can assign values to several variables at once with a single TBL command.
Specifying a table row or column has the same effect as giving a LET command for each entry
in that row or column. Figure 101 shows the essential parts of a table.
Figure 101 The Parts of a Table

Description of Table Parts

You must construct a table as a group.

Part Figure 101 Element Type Function
Defines a name so that you can reference a
particular table. You can have one or more
Title table1 TTB text tables on a sheet. The table name text is
optional if you have only one table on the
sheet. The TTB text must be in a group
Defines the table outline. The LTB line must be
Box LTB line
in the same group as the TTB text.
Defines which variable names take values from
Row and column A B C D
TRC text the table. You can define up to 100 rows and
names R1 R2 R3 R4
100 columns
Values can be any valid expression which
evaluates to one or more numbers, or a string
1.4 12.0...
of characters. Place the text datums at the
2.0...
Values Any text type intersection of horizontal and vertical lines from
2.8...
the row and column text datums. Use either
3.2...
construction lines or a construction grid to
place your values.

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Structure of a Table

Structure of The Table Elements

Figure 102 shows the structure of table elements. The table outline and name text are part of a
group. The group containing the table outline and name text is a sheet element, as are the table
row and column texts and value texts.
Figure 102 The Structure of Table Elements

Sheet

row and column value texts group

texts TRC

table outline LTB table title TTB

You also can put the value, row and column texts into the group with table title and outline in
order to keep the table together.

Additional Table Elements

You can add lines to the table, for example to divide the rows and columns. These lines can be
of any type and are ignored when you give a TBL command. However, if the table is inside a
viewbox, you must make sure that any extra lines you create are placed on an untransformable
layer. This prevents Parametric Design trying to parameterize them along with the object geom-
etry.

Points to Remember When You Use Tables

When you use tables, remember the following:

• The table can have up to 100 rows and columns. This gives you the potential to set 99
variables at once by giving a single command.
• The values in a table can be vectors, text strings, or expressions.
• You can omit angled brackets (<... >) from expressions within a table.
• All the entries in a table must be present before you can access the values.
• If there is only one table on the sheet, the table name is optional.

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Creating a Table

For creating tables MEDUSA provides the following toolset:

Figure 103 Toolset for Tables

The tools from left to right are:

Creates a parametric table boundary line
creates a line of style Parametric Table box line,
type LTB. This line encloses a table in case
that it is placed outside the viewbox of the geometry which shall be parameterized.
After selecting this tool a new group is created automatically in which the line has to
be.
Creates table name of type TTB text
is used after the tool Creates a parametric table boundary line is done. The created table
boundary line has to be active in order to put the text in the same group as the
boundary line, otherwise you get an error message. The text is of type TTB.
Creates table row & column text
is used for creating the table row and column text manually by placing every text
individually on the sheet. This text has to be on sheet level and it is of type TRC.
Creates a parametric table
This tool combines all the tools explained above. For details on using this tool see
“Procedure - Method2” on page 121.

Procedure - Method1

Use the following procedure to create a table:

1. Create the table outline using the tool Creates a parametric table boundary line.
This line is automatically created inside a new group.
2. Name the table using the tool Creates table name of type TTB text.
Table name text must be also part of the new group.
3. Create table row and column texts, with the tool Creates table row & column text.
4. Choose a text tool and define and place text for the table values.
These texts can be of any type but they must be accurately aligned with the row and
column texts.

Please note: If you place the table inside the viewbox of the geometry which shall be
parameterized with this table, do not forget to specify the table outline
untransformable with a layer command text like LAY 14 UNTRN otherwise you
get error messages when parameterizing later on.

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Creating a Table

Procedure - Method2

Use the following procedure to create a table:

1. Create the table using the tool Creates a parametric table.
The dialog Parametric table opens.
Figure 104 Dialog for Defining Tables

The following parameters can be given:

• Table Name is the table identifier and it will be the text of type TTB.
• Variables number is the number of columns the table shall have.
• Entries number is the number of rows the table shall have.
• Change the text height defines the height of all table texts.
2. Type in the Table Name, the Variables number (columns of the table) and the Entries number
(rows).
3. Click left on OK.
The table opens with the defined number of rows and columns.
Figure 105 Example of a Table with 4 entries/rows and 3 variables

The first row entry is selected and you can type in the rows name.

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4. Type in the table entries.

Use the TAB key of your keyboard for doing so. Every time you press the TAB key, the
cursor jumps to the next table cell in the column. If the last table cell of a column is
done, it jumps to the first cell of the next column, which is the name of the variable.
5. After having defined all table entries click left on the button OK.
Now the table is attached to the cursor and you can place it on the sheet.

Table Values

Table values can be of any text type. Use either a MEDUSA 2D grid or construction lines to
place the table values in correct alignment with the row and column texts. If they are not
aligned, it may not be possible to separate the row and column entries when the drawing is
parameterized. If this happens, you will receive the following error message on the screen when
you try to parameterize the drawing:
Cannot resolve table

Variables and Expressions in Tables

Table values can be variables or expressions as well as simple numbers. For example, the table
in Figure 106 shows the values of variables B and C in row Row1 as expressions. Note that the
sequence of variables and expressions in a table is important.
Figure 106 Table With Variables

A B C
Row1 10 A+D B/2
Row2 20 30 40

The value of each variable used in a table refers to its value before the execution of the TBL
command and not to its value calculated during the execution of the TBL command.

Tables and Parametric Symbols

If you include a table in a parametric symbol definition, you must save the geometry, the table
and the in-sheet TBL command together as part of the symbol definition. There is a worked
example in ”Symbols”, “Loading Parametric Symbols With Tables” on page 144 showing how to
load a parametric symbol definition using values from a table.

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Where to Place a Table

Where to Place a Table

When you create a table you place object points on the sheet. If the table is inside a parametric
viewbox the points in the LTB line will be treated like any other point in the viewbox and Para-
metric Design will attempt to parameterize them. To prevent this, do one of the following:
• Place the table outside the viewbox
• Make the layer containing the table untransformable
You can place a table anywhere on the sheet. A table does not have to be in the same viewbox
as the in-sheet command which refers to it.
Untransformable layers are not affected by parameterization. Therefore, you do not have to
place elements on untransformable layers on the grid. When you start up MEDUSA, all layers
are transformable.
To make a table untransformable, use the following procedure:
1. Find out what layer the table elements are on. If you created the table elements using
the tools given in “Creating a Table” on page 120, they will be on layer 14.
2. Create an in-sheet layer command making that layer untransformable, for example:
LAY 14 UNTRN
Make sure that there is nothing on this layer that you want to parameterize.
3. Place the in-sheet command text somewhere inside the viewbox.
If necessary, refer back to ”Layers and Parametric Switches”, “Changing Layer Properties” on
page 110 for more information about changing layer properties.

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Tables

Accessing Values From a Table

You use the TBL command as an in-sheet command to access values in a table.

Please note: If you used “Procedure - Method2” on page 121 for creating tables, you already
have the TBL command. It is at the upper right corner of the table.

How the TBL Command Works

Specifying a row or column of the table with a single TBL command is equivalent to giving a LET
command for each entry in that row or column.
• When you specify a row name in the TBL command, the values for that row are
assigned to the variables specified in the columns
• When you specify a column name in the TBL command, the values for that column are
assigned to the variables specified in the rows

Procedure

These are the steps for accessing table values:

1. Choose the tool Creates free parametric command text .
2. Inside the dashboard insert the text which calls the table and the row whose
parameters you want to use, for example, tbl table1 ’row2’.
3. Place the text inside the viewbox with the geometry which shall be parameterized.
4. Run parameterization using the tool Parameterizes the geometry then immediately undoes .
The geometry should be displayed according to the values defined in the given row.

Please note: If you copy and paste a table on a sheet ensure that you use Recreate Structure from
the popup menu while pasting in order to get the pasted table into its own group.
Otherwise the pasted table is in the same group as its original which causes an
error message when you parameterize it.

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Example

The sheet shown below in Figure 107 has an in-sheet TBL command. When the sheet is
parameterized, the values from the first row of the table, r1, will be used for the dimension vari-
ables D1, D2 and D3.
Figure 107 Example of an In-sheet TBL Command

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Worked Example

This example shows how you can use a table to produce three parameterized versions of an
object.

Drawing the Object

Draw and dimension the object shown below in Figure 108 using the following guidelines:
• The prim datum is positioned at the center of the arc
• The dashed line across the arc ensures that the two collinear horizontal line segments
are supported on the grid. Create the line with the tool Draws lines connecting all collinear
straight lines . Make sure that the connecting line is on an untransformable layer
before parameterization.
• The horizontal 80.0 mm dimension must be a chain dimension in order to pick up the
center support from the prim
Figure 108 Original Component

When you have dimensioned the object, use tool Temporarily draws the grid corresponding to the current
drawing to display the grid. The result is shown in Figure 109.
Figure 109 Dimensioned Component With Grid

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Worked Example

If there are no problems with the grid, test the drawing with the tool Parameterizes the geometry then
immediately undoes . Correct any errors before continuing.

Replacing Dimension Values

The next step is to change the dimension values to variables, as in Figure 110. It isn't necessary
to change all dimension values to variables, as in this example. If you want some dimensions to
remain constant then you can leave them as numeric values.
Figure 110 Changing Dimension Values to Variables

Creating the Table

Next, create the table shown in Figure 111 using the procedure described either in “Procedure -
Method1” on page 120 or in “Procedure - Method2” on page 121. If you intend to use tables fre-
quently, it is best to create a skeleton table and store it as a symbol. You can then load it into
any master drawing that requires a table.
Figure 111 Table of Variable Values

The table is now complete, as shown in Figure 112. If you created the table using construction
lines, delete them before continuing. In a moment you will be able to parameterize the compo-

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nent by selecting a particular row of values from the table. Before that, you must add some in-
sheet commands to the drawing.

Adding in-sheet Commands

Create the following in-sheet commands (text type TCO) and place them inside the viewbox:
This tells Parametric Design which row of dimensions to use. When you

TBL table1 'ROW1' run the tool Parameterizes the geometry then immediately undoes , the values
from ROW1 of the table named TABLE1 will be used. Note that ROW1 must
be enclosed in either double or single quotation marks.
This command prevents Parametric Design trying to parameterize the
outline of your table by making the layer containing the table boundary
LAY 14 17 UNTRN line (layer 14) untransformable. Layer 17 also contains the line you
added with the tool Draws lines connecting all collinear straight lines .

Figure 112 Table and in-sheet commands

Parameterizing the Component Using Table Values

Parameterize the component using the tool Parameterizes the geometry then immediately undoes . The
result is shown in Figure 113. The values from the first row, ROW1, of the table are used to cal-
culate the new dimensions.

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Worked Example

Figure 113 Effect of the temporary parameterization

Further Parameterization

Now parameterize the original drawing using the values in the second and third rows, ROW2 and
ROW3. You can do this by changing the in-sheet command to TBL table1 'ROW2' and TBL
table1 'ROW3' before running the tool Parameterizes the geometry then immediately undoes .

Deleting Elements During Parameterization

When you parameterize a drawing you can prepare the sheet so that unwanted elements are
deleted during parameterization, making the final drawing clearer. For example, in the compo-
nent you draw in the last example you could, if desired, delete the following elements during
parameterization:
• All table elements, including table boundary line (LTB), name text (TTB), row and
column text (TRC) and value texts
• In-sheet commands
• Extra lines you have added to develop the parametric grid
The existing in-sheet command on your sheet makes layer 14 untransformable. This ensures
that Parametric Design does not try to parameterize the table outline when you run the tool
Parameterizes the geometry then immediately undoes . To delete the whole table from the final drawing,

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Tables

make the layer containing all of the table elements deleteable as well as untransformable. For
example:
LAY 14 17 UNTRN DEL

Table values: Remember that table value texts, which can be any text type, will not be on the
same layer as the other table elements by default. You must place them on the same layer. An
easy way to do this is to place a group line around all the value texts then increment the layer
number of the group to make it the same as the other table elements.

Extra lines: Layer 17 contains the extra line added with the tool Draws lines connecting all collinear
straight lines . All extra lines must be made untransformable or Parametric Design will try to
parameterize them. You can then choose whether or not to delete additional lines from the fin-
ished drawing along with the table elements and in-sheet commands.

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Parameterize Variant from a Table

Parameterize Variant from a Table

MEDUSA provides a tool for selecting a variant from a table and parameterize it.

Please note: Consider that variant parameterization is permanent.

These are the steps for using table values for parameterization:
1. Load a sheet with tables used for parameterization.
The tables have to be inside the viewbox (Figure 115, “Example for Variant
Parameterization, Input” on page 132) otherwise variant parameterization does not
work.
2. Choose the tool Selects a variant from a table and parameterizes it .
If there is no parametric table on the sheet an error message is given. Otherwise the
following dialog opens:
Figure 114 Dialog for Selecting a Table Variant

The arrows behind the text fields open pulldown menus.

MEDUSA automatically zooms into the sheet displaying the first table available in the
Tables pulldown menu.
The button Quit aborts the function.
3. Select the table whose entries you want to use for parameterization.
MEDUSA automatically zooms into the sheet displaying the selected table.
4. Select a Variant.
5. Choose Apply to run parameterization.
Parameterization is done immediately.
MEDUSA zooms out displaying the last view before choosing this tool.
The geometry associated with the selected table is parameterized permanently.
6. Go on doing one of the following:
• If you are not satisfied with the result of parameterization, you can undo the
parameterization using the tool Undo from the toolbar.
• If you are satisfied with the result of parameterization, save the sheet with a new
name using the tool Save as from the toolbar, in order to keep the input sheet.

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Figure 115 Example for Variant Parameterization, Input

Figure 116 Example for Variant Parameterization, Result

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SYMBOLS

This chapter describes how to use parametric symbols. A parametric symbol is a a fully dimen-
sioned drawing, complete with reference point, stored in a symbol file. You can parameterize it
as you load it onto a MEDUSA sheet. You can load parametric symbols in one of two ways:
• Interactively, by loading each symbol one-by-one onto a sheet
• Automatically, by parameterizing a sheet containing CPI named groups. CPI named
groups store information about parametric symbols. When you parameterize a sheet
containing CPI named groups, Parametric Design automatically loads and
parameterizes the required symbols.

• Creating Parametric Symbols ................................................ 134

• Loading Parametric Symbols ................................................. 138

• Worked Example 1................................................................. 142

• Loading Parametric Symbols With Tables ............................. 144

• Loading Symbols Using CPI Named Groups......................... 148

• Worked Example 2 - CPI Named Groups .............................. 150

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Creating Parametric Symbols

You should already be familiar with storing and loading symbols in the 2D drafting system. Para-
metric symbols have to be prepared in a special way:
• Before you save the symbol you must add attachment points, text type ATP, which are
used to position the symbol on the master drawing
• To load a parametric symbol onto the master drawing the tool Load parametric symbol is
available, which simultaneously loads and parameterizes a parametric symbol.

Attachment Points

So far, when preparing a drawing for parameterization, you have identified a datum or reference
point by placing a prim or static baselines on the object geometry. When you create a paramet-
ric symbol definition instead of static baselines or a prim you must use one or more attachment
points to specify a reference point.
An attachment point is a text of type ATP. This text consists of a variable name or an expression
that evaluates to a set of X and Y sheet coordinates.

Positioning the symbol using attachment points: When you load a parametric symbol, the
attachment points are used to position it on the new sheet. You can place more than one attach-
ment point in a parametric symbol definition.
With one attachment point, the symbol will be loaded at the same orientation as the original.
You can rotate it with the popup menu while loading, see “Popup Menu while Loading a Symbol”
on page 141.
If you use two attachment points, they can be moved relative to one another, for example to
rotate the symbol as it is loaded. If you want to do so consider that the whole symbol and its
dimensions have to be drawn with a orientation, which is neither horizontal nor vertical, other-
wise the symbol can be placed horizontal or vertical only.

Grid lines: Attachment points generate grid lines in the same way as other reference points.
Two grid lines are generated through the datum of the text, one horizontal and one vertical.
When you display the grid for the symbol geometry, grid lines are drawn along any lines which
pass horizontally or vertically through the attachment points.
If you have rotated the symbol and if you use more than one attachment point, grid lines are
created parallel to the dimension lines.

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Drawing the Symbol

1. Draw a geometry, e.g. a rectangle.

2. Draw a view box.
3. Choose the tool Creates parametric symbol attachment text.
An attachment point is a text of type ATP. This text is a variable name or an expression
that evaluates to a set of XY sheet coordinates.
4. Type the text, e.g. ATP1.
5. Place the text at any point of the geometry.
6. Type another text, e.g. ATP2, and place it also on the sheet.
Now the symbol is finished.

Preparing the Symbol

Once you have created the geometry and added attachment points, you must prepare the sym-
bol definition before saving it into a symbol file.
7. To avoid the constraints caused by special cases, rotate the symbol complete with
supporting lines before dimensioning. Make sure that no lines pass vertically or
horizontally through the attachment points, or at angles of 30, 45, or 60 degrees.
8. Dimension the geometry using the perpendicular and parallel kinds of chain
dimensioning in case you need to rotate the symbol when you load it.
Now your symbol should look like following:
Figure 117 Attachment Points

Testing the Drawing

For testing the symbol do the following:

9. Choose the tool Load parametric symbol from the tooltray Creation Tools.
10.Click left on the view box of the symbol you just created.
11.Choose the button Select from the Load parametric symbol dialog.
The symbol is attached to the mouse pointer.

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12.Define values for the variables if there are some and then click left on the sheet to
place the first attachment point.
13.If you use the example of Figure 117, “Attachment Points” on page 135, click left on
the sheet to place the second attachment point.
The symbol is placed. If it is not, correct any errors before going on.

Some More Preparations Before Saving

14.Replace some or all of the dimension value texts with variables, e.g. replace the
dimension value of the example with the letter h.
15.If desired, you can add in-sheet commands so that certain parts of the symbol are
deleted as the symbol is loaded. You can delete attachment point texts, dimensioning
and tables from the finished drawing using the layer command:
LAY 4 14 DEL.

Saving the Symbol

For saving the symbol,

16.Select the geometry and the attachment points of the symbol.
Consider that you also have to select dimensions and other elements inside the view
box, which define the symbol. Do not include the viewbox for a parametric symbol!
17.Choose the tool Save named symbol from the tooltray Creation Tools.
The selection is saved as symbol and you can use it on other sheets now (see
“Loading Parametric Symbols” on page 138).

Using Tables With Parametric Symbols

Using a table you can load a parametric symbol at a number of positions on your sheet, each
time using a different set of parameters from the table.
The procedure of creating a symbol with a table is as follows:
1. Draw the geometry and dimension it.
2. Replace the dimension texts with variables.
3. Create the table as explained in “Tables” on page 117.
4. Create an in-sheet command for making the table outline, table elements and in-sheet
commands associated with the symbol untransformable and for deleting them when
you load the symbol:
LAY 14 UNTRN DEL
If you used the tool Creates a parametric table for creating the table, then this command is
created automatically.
5. Choose the selection tool Selects elements or groups at sheet level .

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6. Select the geometry, the dimensions, the table and the in-sheet command.
7. Save the selection as symbol using the tool Save named symbol from the tooltray
Creation Tools.
Now you can load this parametric symbol as explained in “Loading Parametric
Symbols With Tables” on page 144.

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Loading Parametric Symbols

If you want to place parametric symbols, you first have to define the values for the variables.
Then, when placing the symbol, it is automatically parameterized.

Dialog

For loading a parametric symbol choose the tool Load parametric symbol inside the tooltray Cre-
ation Tools. The following dialog opens:

Figure 118 Dialog for Loading Parametric Symbol

The parameters of the dialog are:

Filename
is the name of the parametric symbol with full path.
Parametric Values
displays a list of variables defined for the symbol. Click into an edit field, type the value
and then click into another edit field to confirm the value.

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Table
opens a further dialog in which you can select the row whose values shall be used for
parameterization. Table is only activated if you selected a symbol file with table
definition. For details see “Loading Parametric Symbols With Tables” on page 144.
Attachment Points
shows a list of attachment points defined for the symbol.
If you see only one attachment point, it is used for placing the symbol.
If you see more than one attachment point you can change the current point by clicking
on a text inside the list. The selected attachment point is used for next probing on the
sheet. After probing the next attachment point is displayed as selected inside the list
and when probing next time the current attachment point is placed.
Options:
Display Dimensions
shows the symbol, which is attached to the cursor, with applied parametric values and
its dimensions.
Load Dimensions
places the symbol with dimensions on the sheet.
Load if Errors
places the symbol on the sheet also in case that parameterization with the defined
values fails. If this option is off, you can see error messages only at the dimensions of
the symbol attached to the cursor.
The buttons are:
Select chooses the selected symbol with name Filename and displays its variables inside the
dialog. The chosen symbol is attached to the cursor drawn in the manner as it was
constructed, Now you can set values for the variables.
Scale applies the set values to the symbol attached to the cursor. By default the attached
symbol is displayed as it was constructed.
Close undisplays the dialog. The symbol can be placed until you choose Exit Tool from the
popup menu.

Procedure

1. For loading a parametric symbol choose the tool Load parametric symbol inside the
tooltray Creation Tools.
The dialog Load Parametric Symbol opens.
2. Use the File Selector button to choose a symbol file.
3. Click left on the button Select.
The variables of the symbol and its attachment points are displayed.
4. Type in the values for the variables.

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5. If you have more than one attachment point choose that point you want to place first.
At the cursor the chosen attachment point is displayed.
If you do not choose an attachment point the first one is used by default.
6. Choose the button Scale.
The symbol attached to the cursor changes according to the defined values.
7. If you want to rotate or mirror the symbol before placing it, use the popup menu (see
“Popup Menu while Loading a Symbol” on page 141).
8. Place the symbol on the sheet.
You can place the symbol as often as you want. You also can change the values of the
variables and Scale the symbol again.
9. If you finished placing parametric symbols choose Exit Tool from the popup menu.

Making Mistakes When Loading Symbols

Sometimes you may make a mistake when loading a parametric symbol. A common error is to
forget to give a value to a variable. If any problems arise, the unparameterized symbol at the
cursor gives the error messages.
Figure 119 Example for Error Messages while Loading a Parametric Symbol

After you have fixed all errors, the variables are replaced by the values indicating that the sym-
bol now can be placed.
If you suspect that there is an error in the original drawing you saved as a symbol, you can
check this quite easily. Load the symbol into a blank area of your sheet using the tool Load named
symbol and investigate the problem.

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Popup Menu while Loading a Symbol

While the symbol is attached to the cursor you can manipulate the symbol. You can rotate, mir-
ror, revert rotation or mirroring and reselect for choosing a new symbol.
Figure 120 Popup while Loading Parametric Symbol

opens an edit field

below the dashboard Popup Menu while
You also can rotate by rotating by angle
probing on the sheet

Revert resets rotation and mirroring.

Reselect activates the dialog for loading parametric symbols for choosing another symbol with
File Selector. All entries for variables and attachment points are empty after clicking on
Reselect.

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Worked Example 1

This example shows how to load a parametric symbol using the tool Load parametric symbol .

Creating the Symbol Definition

Draw and dimension a rectangle, as in Figure 121. Notice that the reference point is marked
with an attachment point text, type ATP, which contains the variable name P1. Do not replace
the dimension texts with variables yet.
Figure 121 Symbol Definition

Before you can use the tool Parameterizes the geometry then immediately undoes to check that you
have drawn and dimensioned the rectangle accurately, you must give the attachment point vari-
able a value.
1. Choose the tool Creates free parametric command text .
2. Type the following command in the text edit field below the dashboard:
LET P1 = 100 100
With this the rectangle is placed at x=100 and y=100 on the sheet.
3. Place the text anywhere on the sheet but inside the viewbox of the drawn geometry.
If you do not give the attachment point variable a value before running the tool Parameterizes the
geometry then immediately undoes , the error message Unset variable will be written onto the
screen near the variable.
When you display the grid you will see that the attachment point supports grid lines in the same
way as a prim. Grid lines are drawn horizontally and vertically through the attachment point.

Saving the Parametric Symbol

4. When you have replaced the dimension texts with variables, save the parametric
symbol definition using the tool Save named symbol from the tooltray Creation Tools.
Be careful not to save the parametric viewbox with the symbol geometry. Remember
that the position of the probe as you save the group is not significant as the attachment
point and not the probed point is used to position the symbol when you load it onto the
new sheet.

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Loading the Parametric Symbol

You are now ready to load the symbol onto a new sheet.
5. Choose the tool Load parametric symbol inside the tooltray Creation Tools.
The dialog Load parametric symbol opens.
6. Choose File Selector from the dialog.
Another dialog opens for selecting the symbol file to load. After selecting a file name
the dialog closes and the selected file is displayed in the line Filename of the dialog Load
parametric symbol.
7. Choose the button Select.
The dialog updates showing the variables of the selected symbol. In the bottom the
attachment points are given. The symbol is attached to the cursor still showing the
variable names.
8. Specify the values for the variables.
9. Choose Scale.
The symbol attached to the cursor changes and displays the defined values now.
10.Place the symbol on the sheet.
Figure 122 Parametric Symbol Loaded Onto Sheet

11.Now try loading the rectangle at different places on the sheet by moving the cursor to
new locations.
You can change the values but consider to choose Scale to apply the new values to the
symbol before placement.
If you want to rotate or mirror the symbol, use the popup menu.

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Loading Parametric Symbols With Tables

For parametric symbol definitions which may have several sets of variables, you can include a
table of values in the symbol definition. When you include a table in a parametric symbol defini-
tion, make sure that you:
• Include an in-sheet TBL command in the symbol definition
• Make the table (frame and text) untransformable
• Save the table and all in-sheet commands with the symbol geometry
You can delete the table and any in-sheet commands included in the symbol definition when
you load the symbol onto the new sheet.

Example

Using the tool Load parametric symbol , you can load the symbol in Figure 123 using the values
in the table. The only arguments you need to give are a datum position on the new sheet, and
the name of the row of values you wish to use.
First draw and dimension the object shown below in Figure 123. Change some or all dimen-
sions to variables. The original dimension values are not important as you will use the dimen-
sion values in the table when you load the symbol.
Figure 123 Table as Part of a Parametric Symbol

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Creating the Table

When you have finished drawing the object, create the table of values. The table is detailed in
Figure 124. Refer back to ”Tables”, “Creating a Table” on page 120 to see how to create a table.
Figure 124 Table

Adding in-sheet Commands

Finally, you need to add some in-sheet commands.

In-sheet TBL command: In “Tables” on page 117, you saw how to use an in-sheet TBL com-
mand such as TBL table1 'R1' to select a row from a table during parameterization. Every
time you load a symbol using an in-sheet command that refers to an explicit row in a table, the
new object dimensions will be taken from the same row. Replacing the row name in the TBL
command with a variable name enables you to select a different set of dimensions each time
you load the symbol.
When you want to place a row variable in a TBL command instead of specifying a row name,
you must place the variable name inside angled brackets (<... >). For example:
TBL <row>
Using a variable is only needed when loading the symbol with Bacis1 commands. In the graphi-
cal user interface the command can remain unchanged because the row s selected in a dialog
when loading the symbol. You do not need to specify a table name in the TBL command in this
example because this is the only table on the sheet.

In-sheet layer command: You also need to add an in-sheet layer command to the symbol def-
inition to do the following:
• Makes the table outline untransformable
• Deletes the table elements and in-sheet commands associated with the symbol when
you load the symbol onto the new sheet
For example, LAY 14 UNTRN DEL. See ”Tables”, “Deleting Elements During Parameterization”
on page 129 for more information about deleting table elements during parameterization.

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Saving the Symbol

When you have drawn the object and the table and added the in-sheet commands, you are
ready to save them all as a symbol. Make sure that you save the object, table, and in-sheet
commands but not the viewbox. For selecting use the tool Selects elements or groups at sheet level
otherwise you get errors when trying to load the symbol.

Loading the Parametric Symbol

Now load the symbol. The following sequence shows how you might do this:
1. Choose the tool Load parametric symbol inside the tooltray Creation Tools.
The dialog Load parametric symbol opens.
2. Choose File Selector from the dialog.
Another dialog opens for selecting the symbol file to load. After selecting a file name
the dialog closes and the selected file is displayed in the line Filename of the dialog Load
parametric symbol.
3. Choose the button Select.
The dialog updates showing the variables of the selected symbol. In the bottom the
attachment points are given. The symbol is attached to the cursor still showing the
variable names.
4. Choose the button Table to specify the values for the variables from the table saved with
the symbol.
A further dialog opens providing the Table and the Table Records. With the options in
Orientation you can display the specified values for rows or columns.

Figure 125 Dialog Select values from Table

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5. Choose a Table Record and then Select.

The values of the record are displayed in the Load parametric symbol dialog.
6. Choose Cancel to close the dialog Select values from Table.
7. Choose Scale to apply the selected values to the symbol attached to the cursor.
8. Place the symbol on the sheet.
Figure 126 shows the result. The symbol has been loaded onto the new sheet and
parameterized using the values in ROW2 (see Figure 124, “Table” on page 145) of the
table. The table elements and in-sheet commands have been automatically deleted
from the final drawing.
Figure 126 Symbol Loaded Using Teble Values From ROW2

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Loading Symbols Using CPI Named Groups

A CPI named group (CPI=Clump Parametrics Instance) is a special group that instructs Para-
metric Design to load and parameterize a parametric symbol at a specified point. By using CPI
named groups you can load and parameterize automatically several instances of the same
symbol on the sheet.

Toolset

Figure 127 Toolset for CPI Named Groups

The tools from left to right are:

Creates a CPI named group for loading parametric symbols
If you open the structure tree after choosing this tool, you can see the new group. For
renaming it use the right mouse button while the cursor is upon the tree. This opens
the popup menu. Then choose Properties to open the dialog Named group properties, in which
you can change the Name of the group.
Creates SPS text within CPI named group
creates a text of style SPS text. This text has to be the file name of the parametric
symbol with full path.
Creates SCO text within CPI named group
creates a text of style SCO text. This text holds a variable definition, e.g. ARG
var=10. If
the symbol has more than one variable definition you have to define several of these
texts.
Creates SAT text within CPI named group
creates a text of style SAT text.
This text holds the attachment point text as defined
inside the symbol. If the symbol has more than one attachment point you have to
define several of these texts. Ensure that these texts are placed carefully in order to
create no undefined situation when running parameterization.

Creating a CPI Named Group

Use the toolset in the succession the tools are provided:

1. First open a new group of type CPI with the tool Creates a CPI named group for loading
parametric symbols .
2. Create symbol name text using the tool Creates SPS text within CPI named group and place
it on the sheet using a probe.
3. Create command text of text type SCO using the tool Creates SCO text within CPI named group
to assign a value to a variable in the symbol definition and place it on the sheet.
Repeat this step for each variable of the symbol.

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4. Create attachment point text of type SAT using the tool Creates SAT text within CPI named
group and place it on the sheet with a probe. Repeat this step for each attachment
point text of the symbol.
5. Move all CPI named group elements on an untransformable layer.

Please note: For each symbol you want to reference a separate CPI group has to exist.
Do not forget arg in front of variable assignments.

The following example shows a reference with one attachment point and one variable.
Figure 128 Example for a CPI named group

Preparing the Drawing

You must place a CPI named group at all points where you want to load a symbol. Each CPI
named group contains a number of texts, specifying the name, size, and position of each sym-
bol that is to be loaded. You need to create a separate CPI named group for each symbol
instance required. Each CPI named group contains all the information that is required to auto-
matically load a symbol.

Dimensioning Attachment Points

You must dimension the symbol attachment points in each CPI named group to place them onto
grid intersections. Dimensioning the attachment points is critical, as the attachment point
datums must lie at grid intersections when the drawing is parameterized. Use the tool Parameter-
izes the geometry then immediately undoes to check that attachment points lie at grid intersections
after you have dimensioned them.

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Worked Example 2 - CPI Named Groups

This section takes you step-by-step through an example which uses CPI named groups to load
three separate instances of a symbol onto a master drawing. You begin by drawing a gearbox
cover and then create a symbol representing a tab. After adding CPI named groups, you can
load and parameterize the tabs automatically. When you run the tool Parameterizes the geometry then
immediately undoes , the gearbox cover itself will be parameterized, and then each tab will be
parameterized separately as it is loaded onto the master drawing.

Drawing the Component

Draw and dimension the gearbox cover shown in Figure 129 using a view prim as a reference
point. The base of the gearbox cover is horizontal, which prevents the base from being rotated
during parameterization. However, it is still possible to move other parts of the drawing.
When you have finished drawing the component, use the tool Draws the grid corresponding to the origi-
nal drawing and undoes it to display the grid.
Then test the drawing with the tool Parameterizes the geometry then immediately undoes .
Do not proceed unless the drawing can be parameterized.
Figure 129 Dimensioned Component

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Preparing the Component

Change the dimensions to variables as shown in Figure 130. All the variables in this example
have been assigned values using in-sheet commands though you can use a table if you prefer.
See “Tables” on page 117, for information on how to create a table.
Figure 130 Changing Dimensions to Variables

Please note: In all subsequent illustrations, the dimensioning and in-sheet commands shown in
Figure 130 will be omitted. This is for the sake of clarity.

Add lines to the drawing to mark the positions where the tabs will be placed, as in Figure 131.
Figure 131 Marking Positions of Tabs

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The lines used here are type L6, but you can use any line type. Each line is drawn perpendicu-
lar to the outline of the gearbox cover. This is so that when the tabs are added, they will always
be perpendicular to the sides of the component. The length of each line determines the length
of the parameterized symbol. The lines can be any length that you want and placed anywhere
on one of the straight edges of the gearbox cover. In this example the dashed lines are drawn
approximately at the center of each straight edge.
It is useful to place these lines on the same layer as the CPI named group elements, so that
they can all be deleted together during parameterization.

Creating the Parametric Symbol

The next step is to create the symbol for the tabs. Draw and dimension the tab shown below in
Figure 132. Remember to use the parallel or perpendicular kinds of chain dimensioning, rather
than the horizontal or vertical kinds. This allows the tab to be loaded at any orientation.
Figure 132 Dimensioned Tab

Creating the fillets: Add the fillets after you have completed the outline of the component. The
fillets are tangent point fillets, created with the tool Convert the selected circular arc to a tangent point arc
from the Lines+Edit tooltray. The size of the fillets is not really important because they will be
changed to whatever radius is required as you load them.
The important thing is to make sure that there are no coincident points in the drawing. If the end
point of a fillet coincides with another point, the two points will be locked together during param-
eterization. Sometimes you may want certain points to remain locked together. However, it is
usually better to create a master drawing that has no coincident points. Figure 133 shows
where to create the individual points for the fillets.

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Figure 133 Individual Points on the Fillets

Adding attachment points: Add two attachment points variable texts, A and B as shown in
Figure 134 below. These are texts of type ATP and must be linked by a line of any line type.
Place the attachment points and the line linking them on the same layer so that you can delete
them easily when you load the symbol.

Adding an in-sheet command: Add an in-sheet command to delete unwanted elements dur-
ing parameterization, for example, LAY 4 14 DEL. This deletes the layers containing the
attachment point texts, linking line, and dimensioning.
Figure 134 Tab Prepared for Saving

Testing the drawing: When you have drawn and dimensioned the symbol, test it with the tool
Parameterizes the geometry then immediately undoes . If this is successful, change the dimensions to
variables and then rotate the whole symbol through an arbitrary angle, as in Figure 134.
You are almost ready to save the symbol. If you save the in-sheet command with the symbol,
ensure that the layer containing in-sheet commands is deleted during parameterization.

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Creating CPI Named Groups

Having created the tab symbol, you must now create a CPI named group at every position
where the tab is to be loaded as shown in Figure 135. The sequence required to create one CPI
named group is given below. Figure 136 shows one of the CPI named groups in detail.
Figure 135 CPI named Groups in Position

Figure 136 Detail of CPI named Group

Creating a CPI group: First, open a new CPI group using the tool Creates a CPI named group for load-
ing parametric symbols .

Creating SPS text: Then create a new text of type SPS using the tool Creates SPS text within CPI
named group . The SPS text must be part of the CPI group. Enter the symbol file name into the

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text edit field below the dashboard and then place the text on the sheet with a probe. For clarity,
it is best to position the text near to where the symbol will be loaded, although the exact position
of the SPS text is not important. If the symbol is in the same directory as the sheet, no path
need to be given. If you have a sub-directory for symbols, only the sub-path needs to be speci-
fied, but you also can define the complete path. For example:
symbols\gearboxtab.sym

Creating SAT texts: Now create two SAT texts for the attachment points A and B using the tool
Creates SAT text within CPI named group . Make sure that these texts are part of the CPI group by
making the SPS text created previously current before you create the new texts. Type the
attachment point variable names into the text edit field and then place them at the ends of the
dashed line (see Figure 136, “Detail of CPI named Group” on page 154).

Creating SCO texts: Finally, create four SCO texts using the tool Creates SCO text within CPI named
group . These texts contain ARG commands which assign values to the symbol variables.
The exact position of these texts is not important, but they must be part of the CPI group. Make
sure that you end the group when you have finished. For example:
ARG diam = 8
ARG radius = 8
ARG fillet = 4
ARG len1 = 5

Checking CPI named groups: You can verify that all texts are contained within the CPI group
by using the structure tree and clicking left on a CPI group. If you do so, all elements within the
chosen CPI group become selected and they are displayed highlighted. This verifies that they
are associated together in the same group.

Create the other CPI named groups: Once you have selected a CPI group, you can copy and
paste it easily to define the other CPI groups. You then have to rearrange only the attachment
points and adjust the values for the variables according to the current position of the tab. Create
CPI named groups at all the other places where a symbol is to be loaded as shown in
Figure 135, “CPI named Groups in Position” on page 154. Use the variable values shown in
Figure 135.

Dimensioning the CPI named Groups

The symbol attachment points must be dimensioned so that they lie at grid intersections.
Figure 137 shows how to do this. Remember that the main dimensions have been omitted for
clarity. The way that the attachment points are dimensioned is critical. In this example they are
dimensioned from the tangent points of the arcs, easy to probe using the Near probe . They
can be dimensioned in any way that you want, provided that the attachment point datums lie at
grid intersections when the drawing is parameterized.

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Symbols

Figure 137 Dimensioning the Attachment Points

Check that attachment points lie at grid intersections with the tool Draws the grid corresponding to the
original drawing and undoes it . From now on, whenever the shape of the gearbox cover is
changed, the attachment points will also move. This enables the symbols to adjust to the shape
of the component.

Adding in-sheet Commands

Add an in-sheet command to delete all the dimensioning, symbol attachment points, supporting
lines and in-sheet commands on the master drawing during loading parameterization. For
example, LAY 4 13 14 DEL.

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Worked Example 2 - CPI Named Groups

Parameterizing the Drawing

Finally, parameterize the drawing using the tool Parameterizes the geometry then immediately undoes .
The result is shown in Figure 138. The gearbox cover itself is not parameterized because its
dimensions have not been changed. The tab symbol is parameterized and loaded at the three
prepared locations. The tabs are aligned with the attachment points and are drawn using the
dimensions specified in the CPI named groups.
Figure 138 Result of temporary parameterization

Errors during Parameterization

If there is a problem during parameterization, an error message is written next to the SPS text of
the CPI named group that is causing the problem. An error may be due to a problem with the
CPI named group or with the symbol that you are trying to load.

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Symbols

Further Parameterization

Refresh the screen with Refresh Graphics to restore the original drawing. Now change the vari-
able d1 on the gearbox cover to 30.0 mm instead of 15.0 mm and parameterize the component
again. Figure 139 shows the result. This time the gearbox cover itself is parameterized, then the
parameterized tabs are added to the sides. Notice that the tabs have moved with the sides of
the gearbox cover.
Figure 139 Alternative Parameterization

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PARAMETRIC GROUPS

This chapter shows how you can use parametric groups to isolate geometry where dimensions
are to remain unchanged. This enables you to exclude some parts of geometry from parameter-
ization.

• Introduction ............................................................................ 160

• Creating a Parametric Group ................................................. 162

• Example 1: Static Groups ...................................................... 163

• Example 2: Dynamic Group with One Prim ........................... 165

• Example 3: Dynamic Group with Two Prims.......................... 167

• Example 4: Rotating Parametric Groups ............................... 171

• Example 5: Dynamic Group with Three Prims ....................... 172

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Parametric Groups

Introduction

Parametric groups provide a useful way of moving and scaling parts of a drawing without having
to dimension every detail. The detail enclosed in a parametric group is either scaled or ignored
during parameterization depending on the number of prims in the group.

Parametric Group Elements

A parametric group consists of an parametric group line (type LPG) and 0, 1, 2 or 3 parametric
group prims (type PPG).
Figure 140 Structure of a Parametric Group

Sheet

Group

LPG line PPG prim PPG prim PPG prim

Static and Dynamic Groups

The simplest form of parametric group is a static group. This consists of a closed line of type
LPG in a group, and does not include any parametric group prims. Undimensioned points inside
a static group remain in their original position on the sheet during parameterization.
A parametric group which contains an LPG line and one or more PPG prims is known as a
dynamic group. Points within a dynamic group can be moved, scaled, rotated, or differentially
scaled depending on how many PPG prims the group contains.

Points Within Parametric Groups

Normally when you prepare a drawing for parameterization, you must dimension every single
point inside the parametric viewbox. So long as they are not required to move during parameter-
ization, points within a parametric group do not have to be fully dimensioned. This can come in
useful when you are parameterizing drawings containing detailed representations of springs,
knurling, bolts, and so on. Points inside a parametric group that are dimensioned move as
required during parameterization.

Example

The example in Figure 141 shows a bolt. Because the bolt head is included in a parametric
group, the bolt head chamfer does not have to be dimensioned. When the drawing is parame-
terized, the bolt head will not be parameterized but scaled. The three small squares are para-
metric group prims. These are placed on the grid by dimensioning. During parameterization
these prims will move to a position on the new grid: the rest of the points in the parametric group
move will move in relation to the way the prims move.

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Introduction

Figure 141 Parametric Group With Three PPG Prims

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Parametric Groups

Creating a Parametric Group

MEDUSA provides the following tools to create a parametric group:

Figure 142 Toolset for Groups

The tools from left to right are:

Creates parametric group lines
creates a line of style Parametric group line, type LPG.
Creates parametric group boxes
creates a box of style Parametric group line, type LPG.
PPG Prim to create and control dynamic groups
creates a prim of style Para group datum,
type PPG. Such a prim has to be a member of a
parametric group. Up to three prims can be placed for one group.
To create a group:
1. Open a new group.
2. Draw a parametric group line (type LPG) around the detailed parts that you do not wish
to parameterize.
3. If necessary, add up to three prims (type PPG) to the parametric group.
The following example shows a geometry with one group line and one prim. The prim
determines that the holes keep their position relative to the segments close to them.
Figure 143 Example of Preventing Parameterization with Group Line and Prim

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Example 1: Static Groups

Example 1: Static Groups

In this example, the size of the component changes, but the size of the bolts remains constant.
Figure 144 shows a component which has two bolts. You may want the bolt heads to remain
completely static or require them to move together with the main component when the drawing
is parameterized. You can do this without having to dimension the bolts in any detail by using a
parametric group.

Creating the Component

Draw the outline of the component in Figure 144 and then draw the bolt heads and washers.
Use a prim for the reference point. When you have finished drawing the component, dimension
it.
Figure 144 Component with Bolts

Creating a Parametric Group

Begin by opening a new group. This group will contain the parametric group line, a closed line of
type LPG. The line must be part of the group. Draw a closed LPG line around the bolts, as
shown in, Figure 145 and then end the group.

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Parametric Groups

Figure 145 Adding a Parametric Group Line

Parameterizing the Component

Change some of the dimensions of the component and then parameterize the drawing using the
tool Parameterizes the geometry then immediately undoes . Figure 146 shows how the outline of the
component is changed according to the new dimensions but the bolts remain in their original
position.
Figure 146 Result of Parameterization

Note that the bolts are neither parameterized nor repositioned. However the outline is changed,
all undimensioned points in the group remain stationary. The points in the group that are dimen-
sioned (the two points A and B forming part of the outline of the main component) are parame-
terized normally.

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Example 2: Dynamic Group with One Prim

Example 2: Dynamic Group with One Prim

In this example, a PPG prim is used with a parametric group line to move the undimensioned
points in the group with the component as it is parameterized. The prim links the objects inside
the group line to the parametric grid. By placing the PPG prim at a grid intersection, all undi-
mensioned points inside the group will now move in exactly the same way as the prim during
parameterization, although they are neither scaled nor parameterized.

Change the Drawing

Redraw the sheet and restore the original dimensions, as shown in Figure 144, “Component
with Bolts” on page 163. Now make the parametric group line current and then create a prim of
type PPG. The prim looks like a small square. By making the group line current before creating
the prim, you ensure that the prim is part of the same group as the line. Place the prim inside
the parametric group at the point shown below.
Figure 147 Prim Placed Inside Parametric Group

The prim must be placed at an intersection of grid lines, as in Figure 147, otherwise Parametric
Design returns the following error message when you try to parameterize the drawing:
Point not dimensioned

Parameterizing the Component

Now replace the original dimension texts with the new parameters shown in Figure 148 and
then parameterize the component. This time the bolts move in exactly the same way as the
prim. The PPG prim has moved up and left. So have the bolts. Again notice that, although the
bolts have moved, they have not been changed in size.

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Parametric Groups

Figure 148 Change of Dimensions after parameterization

Experiment by changing the dimensions and then parameterizing the drawing again. The group
always moves in unison with the prim.

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Example 3: Dynamic Group with Two Prims

Example 3: Dynamic Group with Two Prims

In this example you will see how two prims can be used with a parametric group to scale the
undimensioned points in the group.

Drawing the Component

Draw and dimension the component shown in Figure 149. Create the horizontal 20.0 mm
dimension on the right side of the shaft separately from the other horizontal dimensioning. This
allows it to be removed in a later operation.
Figure 149 Dimensioned Component

Use intersecting static baselines to specify the reference point. Add the in-sheet command PAR
COL ON. Remember that the PAR COL switch that can be turned on so that grid lines are
drawn along lines which are collinear but which do not overlap (refer back to ”Layers and Para-
metric Switches”, “The PAR COL switch” on page 114 for a description of the PAR COL switch).
Using PAR COL here saves having to dimension the 20.0 mm shaft diameter twice, once on
each side of the component. Draw the grid and then test the drawing with the tool Parameterizes the
geometry then immediately undoes .

Changing the Geometry

Now change the right-hand end of the shaft so that it represents an interrupted view, as shown
in Figure 150. The end of the shaft is constructed by drawing three elliptical arcs. Remove the
20.0 mm horizontal chain dimension on the right side of the component.

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Parametric Groups

Figure 150 Change Made to Component

This interrupted view presents you with an interesting problem. You could dimension the ellipti-
cal arcs at the end of the shaft so that the whole object can be parameterized, but this sort of
dimensioning is tedious and rather pointless. To avoid this, you can draw a parametric group
line around the end of the shaft and then add two PPG prims to the group, as shown in
Figure 151.
Figure 151 Creation of New Group and Addition of Group Line

To create the parametric group, open a new group and then draw a parametric group line
around the end of the shaft, as shown in Figure 151. Keeping the group open, create two PPG
prims and place them at the intersections shown. Make sure that the prims and the group line
are both be part of the group, and that you position the prims accurately.
The prims are placed on the grid by the 20.0 mm diameter dimension. During parameterization,
all undimensioned points in the group will move in the same way as the prims. The component
should now look like the one in Figure 152.

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Example 3: Dynamic Group with Two Prims

Figure 152 Addition of Parametric Group Line

In Figure 152 you can see that the shaft on the right is dimensioned. This means that the shaft
will be parameterized according to how the 20.0 mm diameter dimension changes. The only
undimensioned points in the parametric group are the points that form the elliptical arcs. During
parameterization, these points will move in the same way as the prims move. They will be
scaled, but not parameterized.

Parameterize the Component

Now change the 20.0 mm dimension text on the interrupted shaft dimension to 10.0 mm and
then run the tool Parameterizes the geometry then immediately undoes . The result is shown in
Figure 153.
Figure 153 Parameterized Component

As expected, the diameter of the shaft changes according to the new dimension. If you look
closely, however, you can see that the end of the shaft has been shortened, and that the ellipti-
cal arcs have been scaled down in proportion. It is important to grasp that the diameter of the
shaft is the only part of it that has been parameterized. The rest of it has been scaled to match
the new positions of the prims. The prims, which were 20.0 mm apart, are now 10.0 mm apart.
This means that all undimensioned parts of the group have been scaled by a factor of 10/20. In
other words, the parametric group has been scaled down to half size.

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Parametric Groups

Now change the diameter of the shaft to 35.0 mm and parameterize it again. Figure 154 shows
the result. The shaft has been scaled by a factor of 35/20. The length of the shaft is changed by
the same ratio.
Figure 154 Parameterized Component

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Example 4: Rotating Parametric Groups

Example 4: Rotating Parametric Groups

Using two prims, you can ensure that a parametric group rotates with the rest of the geometry if
necessary. This example illustrates how a bolt hole can be rotated in this way. In the component
shown in Figure 155, one prim lies on the center line of the bolt hole and the other is positioned
so that it marks the width of the hole.
Figure 155 Bolt Hole With Parametric Group

The second prim ensures that the parametric group rotates if the main component rotates. The
20.0 mm hole dimension serves two purposes:
• It allows the diameter of the hole to be changed during parameterization.
• It places the second prim at a grid intersection, allowing the bolt hole to be rotated.
The undimensioned points in the group will move in the same way as these prims move in rela-
tion to each other, as shown in Figure 156:
Figure 156 Rotating a Parametric Group

When the 20.0 mm dimension is changed, the length of the bolt hole is changed as well as the
width. For example, if the width is changed from 20.0 mm to 30.0 mm, the length of the bolt hole
is scaled accordingly. Its new length is 30/20 of its original length. You can set the length of the
bolt hole independently from its width by using a third prim. This is explained in the next section.

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Parametric Groups

Example 5: Dynamic Group with Three Prims

In this example you will see how to parameterize a more complex component without having to
dimension all the intricate details, such as bolt holes.
Figure 157 shows a component that contains three bolt holes. Using three prims, you can differ-
entially scale the parametric group and set the length and width of each bolt hole independently.
Figure 157 Component With Bolt Holes

Drawing the Component

Begin by drawing and dimensioning the component in Figure 157. The reference point is fixed
by two static baselines that intersect at the top right corner of the component. The dashed verti-
cal line through the center of each bolt hole (shown more clearly in Figure 158) enables you to
dimension the holes from the reference point.
Figure 158 Detail of Bolt Hole from Figure 157

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Example 5: Dynamic Group with Three Prims

Creating Parametric Groups

When you have drawn and dimensioned the component, draw a parametric group line around
each hole, as shown in Figure 159. Remember to create a new group for each parametric
group. At this stage add a single PPG prim to each group.
Figure 159 Parametric Group Line

Test the drawing to make sure that it will parameterize. If there are no problems replace some of
the dimensions with new parameters.

Parameterizing

Parameterize the drawing. Figure 160 shows one parameterized version. Notice how the bolt
holes have moved.
Figure 160 Parameterized Drawing

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Parametric Groups

Adding More Prims

The next step is to add two more prims to each parametric group, as shown in Figure 161.
Remember to open the group before creating new prims for each group. Add the 12.0 mm
dimensions. This enables you to set the diameter of each hole when the drawing is parameter-
ized. Finally, add an in-sheet command PAR COL ON. This ensures that the grid line created by
the 20.0 mm dimension at the right side of the component extends to the bottom of the other
bolt holes (which are collinear). You can now change the depth of each hole during parameter-
ization.
Figure 161 Adding More Prims

Figure 162 shows the result of parameterization. Note that the depth, diameter, and positions of
the holes have been changed.
Figure 162 Parameterized Drawing

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POST-PARAMETERIZATION

This chapter shows the functionality of 2D Parametrics which cannot be done with parameter-
ization itself but afterwards therefore it is called Post-Parameterization.

• Overview ................................................................................ 176

• Dialog..................................................................................... 177

• Creating Post-Parametric Definition Sheets .......................... 180

• Callbacks ............................................................................... 182

• Example ................................................................................. 186

• Demo Sheet ........................................................................... 188

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Post-Parameterization

Overview

The purpose of the post-parametric module is to create families of parts by applying user
parameters to procedures attached to MEDUSA graphics groups.
The callback functionality may be used on its own or as an extension to the MEDUSA Paramet-
ric module, for example to arrange multiple copies of a parametric part into an array pattern.
Callback definitions are saved with the sheet.
Precondition for post-parameterization is that geometries are assembled in groups.

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Dialog

Dialog

To bring up the Post-Parametrization dialog press the button Display Post Param Dialog in the Paramet-
tooltray.
rics

Figure 163 Dialog Post-Parameterization

Consider the following things for this dialog:

• For this dialog groups need to be selected as a whole and during partial selection the
dialog will behave as if there is nothing selected.
• When the dialog is first displayed the current selection is auto-escalated to a sheet
level group.
• Also note that during its life the dialog modifies the current selection tool to Selects sheet-
level named groups .
• If the currently selected elements belongs to a group, the group becomes selected
automatically and the first callback for this group is displayed
The options and buttons on the dialog are:
Select or enter callback name
In the pulldown menu below this entry you see a list of internal graphics-modifying
procedures (callbacks) available to assign them to groups. For details see “Callbacks”
on page 182.

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Post-Parameterization

Figure 164 Callbacks available for Post-Parameterization

Highlight all groups on sheet with this callback

Press this button next to the pulldown list to highlight all groups on the current sheet for
which the shown callback is defined.
Selects sheet-level named groups
If the current selection tool is not Selects sheet-level named groups, press this button to switch
back to the tool Selects sheet-level named groups.
Create Primary/Secondary Prim
Some of the callbacks may require up to two datum prims. Use these buttons to create
these prims. After the required prims have been created the tools are disabled. If a
datum prim is missing an error message with yellow background appears in the dialog.
Figure 165 Message for missing primary datum prim

Remove
deletes the callback stored on the selected group. After executing callbacks they are
removed automatically from the group in order to prevent executing them several
times.
Exec
executes the parametric procedure stored on the current group. If you changed
parameters this button is disabled until you Apply the new settings.

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Dialog

Exec All
executes the procedures stored on all groups in the current sheet.
Exec All after parametrization
If this option is switched on, after parameterization all post-parametric procedures will
be run automatically.
OK, Apply
These buttons apply the settings of the current callback. If you use Apply the button will
be disabled and the dialog remains open. OK closes the dialog.

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Post-Parameterization

Creating Post-Parametric Definition Sheets

Before defining a callback function for a certain geometry group, we recommend to look through
the available callbacks. If no group is selected, inside the Post-Parametrization dialog the list Group
parameters is disabled. Use this mode to browse through the available callbacks. The browse text
of the selected callback show you a short description.

Procedure
1. Open the Post-Parametrization dialog with the button Display Post Param Dialog in the
Parametrics tooltray.
You can keep the Post-Parametrization Dialog open while switching between sheets or
changing the sheet selection.
2. Select a sheet level group.
3. Pick a callback.
Instead of selecting from the list you can also type the name of the callback.
4. Enter its parameters and press Apply.
Parameters can be certain values, variables and expressions.
5. After the parameters have been assigned you can press Exec to test-run the callback.
6. Undo the execution because otherwise the callback definitions cannot be stored with
the sheet.
7. Repeat the procedure for any group of geometry which needs to get a callback
definition.
8. If you are finished, save the sheet to store the callback definitions with the sheet
information.

Please note: Consider that a group can get only one callback.

Possible Errors

All expressions are evaluated at the time of entry and invalid ones are shown in yellow. The
browse text of a parameter expression will show you its current value. If the expression cannot
be evaluated the browse text displays Can’t Evaluate.

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Creating Post-Parametric Definition Sheets

Figure 166 Example for an invalid parameter after entering

You should note that at the time of execution a once-valid expression could turn out to be
invalid. In this case the offending expression will be shown in red.
Figure 167 Example for an invalid parameter after running callback

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Post-Parameterization

Callbacks

This section gives all the callbacks distributed with the MEDUSA 2D Parametrics module.
The function of a callback is explained in a browse text, which appears after selecting a callback
and keeping the cursor on the edit field for a moment. The following sections give you some
more information. In addition see the section “Dialog” on page 177.

ppcb_array_copy_angled

This callback copies the geometry of the current group into the direction from first to second
prim (in the dialog it is called Distance along axis) and perpendicular (Distance across axis) to this direc-
tion. The distance and number of copies is defined by the specified values for Copies along and
Copies across the axis.

Figure 168 ppcb_array_copy_angled

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Callbacks

ppcb_array_copy

This callback copies the geometry of the current group in x- and y-direction. The virtual line
defined by the prims specifies the direction of copying as well as the spacing between the cop-
ies in horizontal and vertical direction. The number of copies is defined by the user and it can be
different in x- and y-direction. See also “Example” on page 186.

Please note: The values defined for Copies in X and Copies in Y have to be increased by one. So
the final number of geometries in the array is: (Copies in X + 1) x (Copies in Y +1).
For example, if both values are two, the number of geometries in the array is nine.

Figure 169 ppcb_array_copy

ppcb_multi_copy

This callback copies the geometry of the current group into the direction from first to second
prim. The spacing between the copies is defined by the distance between the prims. The user
obly defines the Number of copies in the dialog.
Figure 170 ppcb_multi_copy

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Post-Parameterization

ppcb_copy_rotate_pcd

This callback copies the selected geometry Total Number times on a circular line of Total Angle
degrees whose center is defined by the prim. The geometries are placed even on the circular
line.
Figure 171 ppcb_copy_rotate_pcd

ppcb_copy_and_mirror

This callback mirrors the geometry at the virtual line defined by the two prims.
Figure 172 ppcb_copy_and_mirror

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Callbacks

ppcb_copy_rotate

This callback copies the selected geometry Number of copies times on a circular line whose center
is defined by the prim. The geometries are placed every Angle degrees on the circular line.
Figure 173 ppcb_copy_rotate

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Post-Parameterization

Example

The following images illustrate the effect of the procedure ppcb_array_copy applied with parame-
ters Copies in X = 4, Copies in Y = 2. The original graphics will be copied 5 times in the X direction
and 3 times in the Y direction using the displacement between the 2 prims as spatial increment.
Figure 174 Example: Parameter Settings in the Dialog Post-Parameterization

Figure 175 Example: Before Parameterization

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Example

Figure 176 Example: After Parameterization

Figure 177 Example: After Running Post-Parameterization

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Post-Parameterization

Demo Sheet

To test the Post-Parametric functionality you can use the demo sheet postparam.she. This sheet
is stored in <installation directory of MEDUSA>\MEDPARA\M2D\DEMOS. It contains several
groups of geometry and each of them runs with a callback procedure.
After loading the sheet, open the Post-Parametric Dialog and press Exec All. Full Undo/Redo is
available.

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SIMULATING MECHANISMS

Using MEDUSA Parametric Design, you can simulate the movement of parts or objects by
repeatedly parameterizing selected dimensions. A mechanism is redrawn on the screen at reg-
ular stages, enabling you to investigate potential clashes between different parts of the mecha-
nism. This technique relies upon repeating a sequence of commands which increase or
decrease the value of variables between repeated parameterization operations.
This chapter contains examples for you to try out.

• Introduction ............................................................................ 190

• Dialog..................................................................................... 191

• Example 1: Repeated Parameterization ................................ 193

• Example 2: Simulating Linear Motion .................................... 195

• Example 3: Simulating Rotary Motion.................................... 197

• Example 4: Using a Program to Simulate Motion .................. 200

• Example 5: Simulating a Working Mechanism....................... 202

• Plotting ................................................................................... 204

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Simulating Mechanisms

Introduction

To simulate the movement of a mechanism, you draw the geometry and set up a parametric grid
using a prim or intersecting baselines and valid dimensions as if you were preparing for normal
parameterization. Enclose parts of the object that will not move within a parametric group, or
leave their dimensions unchanged. Where dimensions will change, replace the text with a vari-
able.

Please note: Remember to make your viewbox large enough to allow the movement you expect
to see.

Repeated Parameterization

By repeating a sequence of commands which increment a controlling variable and parameterize

the object temporary, you can produce several parameterized versions of one drawing. To exe-
cute a sequence of commands to parameterize an object repeatedly, use one of the following:
• The graphical user interface, Mechanisms dialog, described in “Dialog” on page 191.
• A program. Using programs to simulate movement, described in “Example 4: Using a
Program to Simulate Motion” on page 200.

Points to Consider

When you use Parametric Design to simulate mechanical movement, ensure that:
• All parts of the mechanism are inside the parametric viewbox at all times
• The mechanism is adequately dimensioned and tested before attempting to simulate
movement
• Dimensions which are to change are represented by variables or expressions
containing functions of variables
• Variables are given an initial value before any parameterization begins
• Variables are incremented each time the drawing is parameterized
• For Bacis1 programs consider that the PARS command is cancelled each time the
drawing is parameterized

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Dialog

Dialog

For simulating a mechanism MEDUSA provides the dialog Mechanisms which can be opened with
the tool Simulates mechanism motion available inside the toolset for parameterization.
Figure 178 Dialog for Running Mechanisms

The variable definitions are:

Variable
is the name of a variable defined for the geometry you want to simulate. For setting the
values for a variable type its name, define the values and then choose the button Apply.
Start value
is the first value to which the variable is set.
Increment value
is the value by which the current value is increased.
Break value
is the value at which simulation stops.
Maximum steps
is the number of parameterizations which are done per simulation.
Variable list
gives all variables you defined for simulating the geometry. The values on the left are
given for the selected variable.
The options are:
Delay (seconds)
is the time between the single steps. By default the edit field is empty.

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Simulating Mechanisms

Step
is the current step number (for information only).
Stop on first break
stops simulation if an error occurs. By default this option is off.
Clear screen between steps
If this option is off (default), the result of each parameterization is drawn on the screen.
so you get parts of the parameterized geometry one over each other. To clear the
screen after each parameterization, switch on this option.
The buttons are:
OK
closes the dialog. The current settings are stored for later usage.
Apply
uses the current settings. After each run of simulation you have to Apply the settings
again in order to rewind the sequence to its beginning (see currently displayed Step
number)
Delete
removes the currently selected variable from the Variable list.
Defaults
replaces the values of the current Variable with the default values.
Cancel closes the dialog.
Buttons for running simulation
The left buttons run one step of the simulation, forward or backward.
The right buttons run the whole simulation, forward or backward. until the number of
Maximum steps or until the first break point.
The buttons for running simulation backward do work as recently as simulation was
done forward.
Each parameterization step accords with the singular usage of the tool Parameterizes the
geometry then immediately undoes . So, if you redraw the graphics the parametrization
result disappears and the original drawing is shown again.
Help opens the appropriate page in the online documentation.

The following steps show you how to run a simulation:

1. Draw the geometry and dimension it.
2. While dimensioning use the tool Draws the grid corresponding to the original drawing and undoes it
for checking the grid.
3. If the geometry is finished replace dimension values with variables or expressions.
4. Choose the tool Simulates mechanism motion for opening the Mechanisms dialog.
5. Define variables and insert their values. Specify options if you want to use them.
6. Apply your settings.
7. Run simulation with the buttons .

Please note: Simulation settings are valid for the current MEDUSA session only.

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Example 1: Repeated Parameterization

Example 1: Repeated Parameterization

This example shows how to use a text variable command to repeatedly parameterize an object.
No movement is simulated in this example but in the next example you will use the same tech-
nique to move an object across the screen.
Draw and dimension a rectangle, as in Figure 179. The actual width and height are not impor-
tant. Before you replace the dimension texts with variables, add the prim and then test to see if
the drawing can be parameterized using the tool Parameterizes the geometry then immediately undoes .
Then change the dimension values to variables, as shown.
Figure 179 Drawing to be Parameterized

Adding in-sheet Command

To ensure that dimensioning and in-sheet command text do not appear on each parameterized
drawing, add the command LAY 4 14 DEL.

Setting Values

Now open the Mechanisms dialog with the tool Simulates mechanism motion and define the parame-
ters as given in the following figure.

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Simulating Mechanisms

Figure 180 Settings for repeated parameterization

Running Simulation

You can see the result in Figure 181. The rectangle is repeatedly parameterized by changing
the value of the variable len. The variable len was increased by 5 mm for each parameteriza-
tion.
Figure 181 Result of Repeated Parameterization

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Example 2: Simulating Linear Motion

Example 2: Simulating Linear Motion

This is a simple example showing how to simulate linear motion. You will parameterize an
object so that it moves across the screen, 5 mm further at each step.
Begin by creating the drawing shown in Figure 182. Use any convenient dimensions. Note the
position of the prim. When you have drawn and dimensioned the object, add the variable
parameter dist, as shown in Figure 182. This enables you to move the object away from the
prim.
Figure 182 Object Definition Drawing

Adding in-sheet Commands

To ensure that dimensioning (layer 4) and in-sheet command text (layer 14) do not appear on
each parameterized drawing, add the in-sheet command LAY 4 14 DEL.

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Simulating Mechanisms

Setting Values

Now open the Mechanisms dialog with the tool Simulates mechanism motion and define the parame-
ters as given in the following figure.
Figure 183 Settings for linear motion

Running Simulation

Figure 184 shows the result after running the simulation forward. For displaying only the last
parameterization switch on the option Clear screen between steps.
Figure 184 Result of Simulating a Motion

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Example 3: Simulating Rotary Motion

Example 3: Simulating Rotary Motion

This example shows how you can use Parametric Design to simulate the rotary movement of a
simple component which turns around its center. Later, two reciprocating rods will be added to
the component to form a working mechanism.

Drawing and Dimensioning the Component

Draw the component shown in Figure 185 at a horizontal orientation and then rotate it so that it
is not constrained to remain horizontal during parameterization.
Consider that the position where static baselines cross is the center point for both big circles.
The center of the small circle is on the line of the inner big circle. Each circle is dimensioned
with diameter dimensioning. The angle dimension is between the center of the small circle and
the 15 degree baseline
Figure 185 Component Definition

Dimension the component once you have rotated it, as in Figure 185. Test the drawing with the
tool Parameterizes the geometry then immediately undoes . Do not proceed unless it can be parameter-
ized.

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Simulating Mechanisms

Adding in-sheet Commands

To ensure that dimensioning (layer 4) and in-sheet command text (layer 14) do not appear on
each parameterized drawing, add the in-sheet command LAY 4 14 DEL.

Changing Dimension Values to Variables

Change the angular dimension values to variables, as in Figure 186. Save the sheet before
continuing. You need this sheet for the next example.
Figure 186 Replaced angular dimension values by variables

Setting Values for the Variable

Now open the Mechanisms dialog with the tool Simulates mechanism motion and define the parame-
ters:
• Start Value = 0
• Increment Value = 15
• Maximum Steps = 15
• Delay = 0.5 seconds
Apply the settings and then use the buttons for simulation.

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Example 3: Simulating Rotary Motion

Result of Simulation

Figure 187 shows the result after running the whole simulation forward. For displaying only the
last parameterization switch on the option Clear screen between steps.
Figure 187 Result of Simulating a Rotation

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Simulating Mechanisms

Example 4: Using a Program to Simulate Motion

Besides running simulation in the graphical user interface using the dialog Mechanisms, you also
can use a Bacis1 program. A program is a file containing a number of MEDUSA commands and
it can be used to repeat a sequence of commands.

Creating the Component

This example uses the component you created in the last example, “Example 3: Simulating
Rotary Motion” on page 197.

Writing the Program

You can create a program in two ways:

• Using your operating system text editor
• Using MEDUSA program mode
Details of how to create programs are given in the manual MEDUSA Bacis1 Guide.

Using a text editor

The example below shows a simple program which parameterizes the component you have
drawn. To begin with, ANG is set to 40 degrees. The PARS CAN command is placed inside a
loop which parameterizes the component repeatedly.
10 LET ANG = 40
20 LOOP
30 PARSCAN
40 BREAK IF (ANG.GT.100)
50 LET ANG = (ANG + 30)
60 ENDLOOP
70 ENDRUN
With each loop, the program does the following:
• Parameterizes the component temporarily with the PARS CAN command
• Uses a logical operator to test if the value of ANG is less than 100 degrees: if this
evaluates to true, then the program increments the value of ANG by 30 degrees
• If ANG is greater than 100 degrees, then the program stops

Please note: It is not possible to use PARS instead of PARS CAN in command loop. You will

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Example 4: Using a Program to Simulate Motion

generate error if you do use PARS because the drawing resulting from the first
PARS command will be used as input for the next. This causes problems as there
is no guarantee that a drawing produced by parameterization is itself capable of
being parameterized. A drawing that is the result of parameterization may contain
geometric constraints, such as coincident points or horizontal and vertical lines,
which prevent it from being parameterized

Program mode

The following example shows how to create the simple program shown above using MEDUSA
program mode. In this example, the file containing the parameterization program is called
MECH1.PRG. User input is shown in bold text.
*PROGRAM
Program>AUTO 10 10
10 LET ANG = 40
20 LOOP
30 PARSCAN
40 BREAK IF (ANG.GT.100)
50 LET ANG = (ANG + 30)
60 ENDLOOP
70 ENDRUN
80 PROGRAM
Program>SAVE MECH1.PRG
PROGRAM saved on file: MECH1.PRG
Program>COMMAND

Running a Program

When you run the program, first clear the screen with the CLE command and then type RUN
followed by the name of the file containing the program:
*CLE
*RUN MECH1.PRG
Figure 188 Result of Repeated Parameterization

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Simulating Mechanisms

Example 5: Simulating a Working Mechanism

In this example you combine rotary motion with two reciprocating rods to produce a working
mechanism.
Take the drawing you created in “Example 3: Simulating Rotary Motion” on page 197.
1. Draw two circles near to it, as illustrated in Figure 189. The new circles act as pivots for
a rod.
2. Draw tangential lines between the new circles to create two rods. Use the tool Creates
construction lines through tangential chord of circles from the tooltray Creation tools for designing
them.
3. Dimension the new geometry. After each dimension use the tool Draws the grid
corresponding to the original drawing and undoes it for checking whether the grid is correct.
4. To complete the definition drawing, place a PVG prim at the center of the lower circle.
The prim creates grid lines in the same way as the baselines at the other end of the
mechanism. More important, the prim locks the circle into its current position. When
the component rotates, the two rods will move, but the circle marked with the prim will
remain fixed.
Figure 189 Adding Two Circles and Two Rods

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Example 5: Simulating a Working Mechanism

Use the same settings for the variable ang as defined in “Example 3: Simulating Rotary Motion”
on page 197. Apply the settings and then use the buttons for simulation. Figure 190 shows the
result after running the whole simulation forward. For displaying only the last parameterization
switch on the option Clear screen between steps.
Figure 190 Simulated Mechanical Movement

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Simulating Mechanisms

Plotting

It is not possible to plot the screen display to show all the movement of the mechanism. You can
only plot the master drawing that is used for each parameterization.
The reason for this is that you parameterize the drawing temporary, not permanent. The master
drawing is redrawn with new dimensions, but parameterization is immediately cancelled. When
you plot a sheet, you get the information in the master drawing, not simply what you see on the
screen.

Getting a Screen Dump

One way to get around this problem is to get a screen dump.

• On UNIX machines you can only obtain a screen dump if there is a hardcopy device
attached to your workstation.
• Under Windows you can use the print screen button on your keyboard. Then paste the
contents of the clipboard into an image editing program and print it.

Creating a Composite Drawing

If you cannot get a screen dump, you can create a composite drawing of the mechanism using
the following procedure.
1. Increment the variable in the master drawing.
2. Parameterize the drawing permanently.
3. Save the sheet as a symbol.
4. Increment the variable on the master drawing by a further step.
5. Parameterize the drawing again.
6. Save the sheet as a symbol, using a new filename.
Continue this procedure until you have a symbol representing each stage in the movement of
the mechanism. Then load all the symbols onto the same sheet to form a composite drawing
which can be plotted.

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OTHER APPLICATIONS

The Parametric Design system can be integrated with other MEDUSA software. This chapter
gives some examples where Parametric Design has been applied to the MEDUSA 3D Design
system and the MEDUSA Sheet Metal Design system.
The purpose of this chapter is to show what is possible. It is not intended to be a detailed refer-
ence.

• MEDUSA Applications ........................................................... 206

• Parametric Design and 3D Modelling .................................... 207

• Parametric Design and Sheet Metal Design .......................... 212

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Other Applications

MEDUSA Applications

The name MEDUSA covers a variety of applications software including the following:
• MEDUSA 2D Design system
• MEDUSA Parametric Design
• MEDUSA 3D Design system
• MEDUSA Sheet Metal Design System
• NC definitions

2D Design System

The basic system is the 2D drafting system. This must be installed before any of the other pack-
ages can be used. The other applications can be added separately, as and when required.

3D Design System

The 3D design system takes a specially prepared 2D drawing and then turns it into a 3D model.

Sheet Metal Design System

The Sheet Metal Design system takes a specially prepared 2D drawing (or a 3D model) of an
object and then calculates the true shape of the unfolded metal required to make it.

NC Definitions

Information from a specially prepared 2D sheet is used to define machining operations such as
turning and milling.

Parametric Design and MEDUSA Applications

The common factor running through all these applications is that they take their information
from a 2D drawing. The heart of MEDUSA is the 2D product. Any 2D drawing can be parame-
terized, so it is a simple step to parameterize a drawing and then use the drawing as input to
one of the other MEDUSA applications.

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Parametric Design and 3D Modelling

Parametric Design and 3D Modelling

To parameterize a 3D model, you begin by drawing a 2D representation of a component on a

3D definition sheet. This section gives the procedure for an example consisting of a profile
which has a hole of certain shape.

First draw the hole:

1. Open a 3D sheet and go to the XY view.
2. Draw the geometry with a profile line as given in the figure below (green circle with six
pivots). Ensure that the center is identical with the datum point of the 3D DXY prim.
3. Dimension the diameter of inner and outer circle and the width of each pivot.
4. Dimension the angles between the upper and lower pivots (other angles need no
dimension because of the 3D center line). Use the tool Creates construction lines at 30, 60, 120
and 150 degrees to place the dimension lines properly on the center of the pivots area.
Figure 191 Example 3D Modelling, Hole

5. Choose the tool Draws the grid corresponding to the original drawing and undoes it for checking
the grid lines.

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Other Applications

Now draw the plate:

6. Go to the XZ view.
7. Draw the profile as given by the green outline in the figure below. A center line need
not to be drawn because it is already on the 3D sheet
8. Dimension the profile.
Figure 192 Example 3D Modelling, Plate

9. Choose the tool Draws the grid corresponding to the original drawing and undoes it for checking
the grid lines.

Prepare the drawing for parameterization:

10.Define a variable for the width of the pivots of the hole, e.g. zw.
11.Define a variable for the outer diameter, e.g. hd1 and use it for the inner, e.g. hd1-7.
12.Define a variable and replace some dimension values of the plate with expressions
using the specified variable.
See Figure 193, “Example 3D Modelling, Prepared for Parameterization and
Modelling” on page 210 for examples.
13.Choose the tool Creates free parametric command text to assign values to the variables,
e.g. let zw=10, let hd1=40 and let hd2=20.

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Parametric Design and 3D Modelling

14.Use the same tool to place the parametric command Text LAY 7 28 UNTRN in one of
the view boxes in order to prevent 3D center and link lines used for parameterization.

Prepare for 3D modeling:

15.Draw a link line of style Slab Generator (tool Link line for linear sweeping ) from the hole to
the plate starting at any point of the hole. The next two points define the height of the
hole and also they have to be on points of the plate geometry.
16.Draw a link line of style Volume Revolution (tool Link line for rotational sweeping ) from the
plate to the hole starting at any point of the plate which is not part of a horizontal
segment. The next point is in horizontal direction (to ensure this, use the protractor) on
the center line and it finishes at the datum point of the XY prim in the view with the
hole.

Please note: If a point of the Link line for rotational sweeping does not coincide with a point of the
geometry, parameterization fails because it detects such point of the link line as
an undimensioned point.

17.Name the link lines:

a. Choose the tool Creates and manipulates 3D texts from the 3D tooltray.
The dialog 3D Texts Controls - Line mode opens.
b. Inside the drawing area click left on the link line you want to name.
The dialog 3D Texts Controls - Line mode lists all texts you can define now.
c. Choose the text MODEL: NAME A and add it to the right list Actual Commands.
d. Select the added text in the right list and name the link line by typing inside the field
Values, e.g. Hole.
e. Choose the button Edit for using the new name (the right list is updated).
f. Choose the button Create to attach the text to the cursor.
g. Click left close to the link line to place the name on the link line.
h. Repeat the steps for the other link line.
18.Now you have to define that one geometry will be the hole in the other geometry:
a. Again choose the tool Creates and manipulates 3D texts .
b. Click left on the sheet but not inside any view box.
In the dialog 3D Texts Controls - Sheet mode you see all Possible Commands on the left side.
c. Scroll the list until you find the entry MODEL: MAKE A - B and add it to the right list.
d. Select the added text in the right list and replace A by the name of the plate and B by
the name of the hole. Now you should see something like that:
MODEL: MAKE Plate - Hole
Ensure that there is a space between names and minus sign. If you run modelling
later one, this command works like subtracting the Hole from the rotated profile Plate.
e. Choose the button Edit for applying the command and then Create for attaching it to
the cursor.

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Other Applications

f. Click left on the sheet but not inside any view box to place the command.
You should have now a drawing like in the figure below (consider that the MAKE
command was moved into the XZ view only to show it, it has to be outside of any
view!).
Figure 193 Example 3D Modelling, Prepared for Parameterization and Modelling

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Parametric Design and 3D Modelling

Running parameterization and 3D modelling:

19.Assuming that the grid is already checked, choose the tool Parameterizes the geometry then
immediately undoes to parameterize the drawing temporary.
20.If everything is fine, run the tool Parameterizes the geometry to parameterize
permanently.
21.Save the sheet under a new name in order to keep the input sheet for further
parameterizations.
22.Run 3D Modelling with the tool Produce model from current sheet and draw it .
According to the variables you used for parameterization the model is drawn.
Additionally a model file is written using the sheet name with extension mod.
23.Choose the tool Open model Viewer to display the model.
Figure 194 Example 3D Modelling, Possible Results

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Other Applications

Parametric Design and Sheet Metal Design

You can parameterize an initial definition sheet and produce a whole range of differently folded
components from a single drawing. Figure 195 shows two parameterized versions of a box.
Figure 195 Parametric Design and MEDUSA Sheet Metal Design

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APPENDIX A PARAMETRIC DESIGN ELEMENT

DEFAULTS

This appendix gives a brief summary of the element type and layer defaults for elements used
in Parametric Design.

• Basic Parametric Elements.................................................... 214

• Tables, Symbols, Groups and Error Messages...................... 215

• Graphical User Interface ........................................................ 216

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Appendix A Parametric Design Element Defaults

Basic Parametric Elements

The following table shows the type and layer defaults for some basic Parametric Design ele-
ments. You will use some of these elements whenever you use Parametric Design.
Element Element type Layer
Parametric viewbox LPV line 28
Static baselines LBL line 4
Dynamic baselines LBL line 16
Reference prims PVG, DXY, DYZ, DZX, DYZ, DZY, DXZ prims 4
Grid lines STK line 99
Lines created by the PAR GRIS options
L3 line 17
COL and CIR
In-sheet commands TCO text 14

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Tables, Symbols, Groups and Error Messages

Tables, Symbols, Groups and Error Messages

Parametric Table Elements

These elements are used in tables. Use a table when you need to store a number of values.
Element Element type Layer
Table boundary line LTB line * 14
Table name text TTB text * 14
Row and column names TRC text 14
Table entries Any other text 14

* These elements must be part of a group.

Parametric Symbol Elements

These elements are used for creating parametric symbols and instance groups.
Element Element type Layer
Symbol attachment point ATP text 13
Symbol name SPS text * 13
Instance group attachment point SAT text * 13
Instance group command SCO text * 13

* These elements must be part of a CPI group.

Parametric Group Elements

These elements are used in parametric groups.

Element Element type Layer
Parametric group line LPG line* 15
Parametric group prim PPG prim* 15

* These elements must be part of a group.

In-sheet Error Message Elements

These elements are used in error messages that are written onto the sheet.
Element Element type Layer
Error texts TS1 or TR1 text 99
Error lines L6 line 99

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Appendix A Parametric Design Element Defaults

Graphical User Interface

MEDUSA provides a dialog, which gives you most of the element types used for Parametrics
and which allows you to change them temporary for the current session.
For opening the dialog Parametric Data Definition choose the tool Display the current settings of the paramet-
ric line styles from the tooltray Parametrics.
Figure 196 Dialog Parametric Element Types

Consider that for parameterization 3D prims can be used (entry Datum prim (PVG), values DXY,
DYZ etc.).
For details on changing parametric element types see the Parametrics Reference Guide, chap-
ter „Changing Element Types“.

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APPENDIX B ERROR AND WARNING MESSAGES

This appendix gives an alphabetical list of error and warning messages that occur in the Para-
metric Design system.
Any relevant MEDUSA error message can also appear either in the sheet or on the screen. For
information on MEDUSA error messages, refer to the MEDUSA Bacis1 Design Commands
Guide.

Ambiguous Construction

The new grid on which the construction is based does not result in a unique set of grid lines.
When a construction has unnecessary supporting grid lines, Parametric Design uses only the
minimum necessary to support the construction. The remaining grid lines are then checked for
consistency. This error is normally caused either by over-dimensioning, or by using a tolerance
that is too large. Use the tool Draws the grid corresponding to the original drawing and undoes it to identify
the grid lines that are used to support the construction.

Ambiguous Point

This point is at a point on the old grid that does not transform to a unique point on the new grid.
This is because the grid lines which intersect at the point in the old grid do not all intersect at the
same point in the new grid. This error is normally caused by over-dimensioning or by using a
tolerance that is too large. Use the tool Draws the grid corresponding to the original drawing and undoes it
to identify the grid lines that intersect at the point.

Cannot Resolve Table

The table cannot be separated into rows and columns with the same number of entries in each
row and in each column. Check the types, positions and number of texts in the table.

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Appendix B Error and Warning Messages

Element Types Insufficiently Specified

This error occurs if one of the construction elements used as input to Parametric Design does
not have a valid type specified for it. This is most likely to be a problem in the DDL, as the Para-
metric Design system has a complete set of defaults.

Fatal Error During Dimensioning

This error is produced when parameterization is executed and an error is found in your dimen-
sioning, for example a corrupt dimension group.

Group Datums Define Impossible Transformation

This error is normally caused by coincident or collinear datum points in a parametric group.

Illegal Context for Element

This error is produced when you use tool Load parametric symbol and an element is found in the
symbol definition which is not valid as input to Parametric Design.

Illegal Dimension Type

Axonometric and tolerance limit dimensions are not supported by Parametric Design. See
“Dimensioning” on page 25, to see which dimensioning types you can use as input to Paramet-
ric Design.

Illegal Expression

An expression has been used to define a variable which includes an invalid operator or function.
See “Variables and Expressions” on page 91, for a list of valid operators and functions.

Illegal Point/line Function

The point function used on the baseline indicated is not recognized by Parametric Design. See
“Geometric Constraints” on page 75, for more information on point functions.

Illegal Variable Name

The text indicated should be a valid variable name. This message may occur with symbol
attachment points and table row and column names.

Illegal Viewbox Definition

The viewbox indicated interferes with other viewboxes in the sheet. Viewboxes may not overlap
or be nested. The X and Y limits of each viewbox line are used when testing for overlap. The
other viewboxes are processed as normal.

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No Constructions in Viewbox

No grid was generated because there was no valid construction in the viewbox. This is either
because there are no dimensions or other constructions in the viewbox, or the constructions are
on unhittable layers.

No Current Sheet

There must be a current sheet before you can execute any commands

No Solution Possible

The point or construction has no solution in the new grid. For example, a point may lie at the
intersection of two circular grid lines in the old grid, but in the new grid the circles are too far
apart to intersect.

No Supporting Grid(s)

The construction indicated does not have sufficient grid lines to support it. Use the tool Draws the
grid corresponding to the original drawing and undoes it to examine the existing grid. This should reveal
the missing link that is required to build up the grid. If the PAR BAS switch is OFF, you may
need to add a dynamic baseline.

No Table Found

No table with the specified name can be found. If you give TBL command as an in-sheet com-
mand in a parametric symbol definition, the search is restricted to the symbol containing the
command.

No Viewboxes in Sheet

The Parametric Design system only processes geometry which is inside a parametric viewbox.

Obsolete command GLMT, use PAR LIM

Obsolete command GLME, use PAR LIM
Obsolete command GLRAD, use PAR LIM
Obsolete command QGLRAD, use PAR LIM

These error messages relate to obsolete Prime Variational Geometry commands for displaying
parts of the grid. Use the PAR LIM switch instead. When the PAR LIM switch is ON, the grid
lines extend to the edges of the viewbox.

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Appendix B Error and Warning Messages

Point Not Dimensioned

The point indicated does not lie on a grid intersection. All line points must lie on grid intersec-
tions. This message may be the result of under-dimensioning, but can also be caused by inac-
curate drafting, where points that should be coincident are not quite coincident. The error can
also occur if the end points of dimensions are not at grid intersections. Be careful to probe the
correct points when you are dimensioning objects.

Problem With Construction

Some unidentified problem has occurred with a construction. This is often due to zero length
baselines or expressions that evaluate to the wrong data type.

Problem with Parametric Group Datums

An internal problem has occurred with the parametric group datum points.

Problem with Parametric Group Line

A problem has occurred in creating a test polygon from the parametric group line.

Problem with VAR to LIM Conversion

This message is displayed following the unsuccessful completion of displaying the grid or
parameterization. A problem has occurred in attempting to convert a VAR dimension to a LIM
dimension. Refer to the MEDUSA Parametric Design Reference Guide for more information
about this message.

Row/col not Found

The specified text string cannot be found as a row or column name in the specified table.

Row/col text Not Outside Body Texts

The row and column texts must be outside the area of the table containing all the entries.

Specified type is not a line

Specified type is not a prim
Specified type is not a text

These errors are due either to a problem in the DDL or an invalid type specified in the PAR DDL
command. Refer to the MEDUSA Parametric Design Reference Guide for more information
about the PAR DDL command.

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System error - Automatic Baseline Buffer Overflow

Grid lines that cross the potential grid line are stored in an buffer. When this buffer overflows
you will see the message above. This means that a baseline will not be automatically gener-
ated. This buffer is also used with output radial dimensions. To avoid the problem you can add a
baseline explicitly.

System error - Grid Finding Buffer Overflow

Each grid lines that passes through a point is stored in a buffer. When too many grid lines pass
through a point this buffer overflows and you will see the message above.

System Error - Element Type Storage is Full

This error may occur when you use the PAR DDL command to define new element types. The
maximum number of element types you can define with the PAR DDL command is 50. Sixteen
are defined by default. Refer to the MEDUSA Parametric Design Reference Guide for informa-
tion about the PAR DDL command.

System Error - Parametric Workspace is Full

This error is normally caused by having too many dimensions in one viewbox. The workspace is
used for storing information on the constructions and grid lines.

System Error - too Many in-sheet Commands

The maximum number of in-sheet commands in a viewbox is 200. Less may be allowed if you
use large numbers of variables.

Too Few Rows/columns/entries

There must be at least one row, one column and one entry in a table.

Too Many Datums in Parametric Group

The maximum number of datum points in a parametric group is three.

Too Many Entries in Table

The maximum number of entries in a table is 2500.

Too Many Parametric Groups

The maximum number of parametric groups in a viewbox is 100.

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Appendix B Error and Warning Messages

Too Many Rows and Columns in Table

The maximum total number of rows and columns in a table is 100.

Too Many Viewboxes

The maximum number of viewboxes in a sheet is 20.

Trying to Move Point Outside max. area

When you parameterize an object, no points can be moved outside the maximum drawing area.

Typing Mistake!

This error is the result of bad command syntax either in an in-sheet command or in a command
that you have entered directly. This error also appears, if you used for an attachment point text
the wrong text type, e.g. TCO instead of ATP.

Unable to Convert Dimension

The PAR DIM option VTL has failed. Either the VAR dimension being converted or the resulting
LIM dimension is invalid. Refer to the MEDUSA Parametric Design Reference Guide for more
information about the PAR DIM command.

Unable to Load Sheet File

This error occurs when you try to load a parametric symbol definition which is does not exist or
is not readable. Make sure you have given the correct pathname for the symbol file.

Unknown Element Type

This error is generated when you try to specify an illegal element type in the TBL DDL com-
mand. Refer to the MEDUSA Parametric Design Reference Guide for information about the
TBL DDL command.

Unset Variable

This error occurs when you try to display the grid for or parameterize geometry which includes a
variable that has no value.

Warning - Ambiguous Dimension Texts Interpreted as Values

One or more dimension texts may have been interpreted as simple values with a prefix text, but
the texts could also have been interpreted as variable names. Alternatively, the dimension text
may have been interpreted as both a value produced by dimensioning and also as an expres-
sion.

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Warning - Messages Written into Sheet

This message is output to the screen whenever error messages are written into the sheet.

Warning - no Grid Lines Drawn, as PAR LIM switch is OFF

Certain grid options are only available with limited grid lines, that is, when the PAR LIM switch is
ON.

Warning - PARDIM command interrupted

Warning - PARGRIS command interrupted
Warning - PARLOA command interrupted
Warning - PARS command interrupted

These messages will appear when you interrupt any of these commands.

Warning - point(s) Scaled Outside Viewbox

One or more points were moved outside the viewbox when the elements were moved.

Warning - Protected Elements Not Transformed or Deleted

Elements on protected layers cannot be transformed or deleted by the Parametric Design sys-
tem. However, they can be used during the creation of the grid. This warning occurs if there are
elements on a hittable but protected layer that may also be transformed or deleted.

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Appendix B Error and Warning Messages

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LIST OF FIGURES

Figure 1 Changing the Dimensions of an Object . . . .10 Figure 37 Toolset for Drawing Grids. . . . . . . . . . . . . . . 46
Figure 2 A Family of Parts Made From a Single Master Figure 38 Dialog Grid construction . . . . . . . . . . . . . . . . 48
Drawing. . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 Figure 39 Toolset for Parameterizing . . . . . . . . . . . . . . 50
Figure 3 A Symbol Library Created Using Parametric Figure 40 Error Messages . . . . . . . . . . . . . . . . . . . . . . 51
Design. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 Figure 41 Example1: Rectangle with DXY Prim Reference
Figure 4 Simulation of the Movement of a Lift Arm As- Point . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
sembly. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 Figure 42 Example1: Effect of Drawing Grid . . . . . . . . 54
Figure 5 Examples of Parametric Viewbox Shapes . .14 Figure 43 Rectangle Dimensioned for Parameterizing . 55
Figure 6 Intersecting Static Baselines. . . . . . . . . . . . .15 Figure 44 After Parameterization . . . . . . . . . . . . . . . . . 56
Figure 7 The Parametric Design Datum Prim (Type Figure 45 Example2: Rectangle with Intersecting Base-
PVG) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Figure 8 Orthogonal View Prims . . . . . . . . . . . . . . . . .16 Figure 46 Effect of Changing the Grid Tolerance . . . . . 59
Figure 9 Positioning Baselines . . . . . . . . . . . . . . . . . .16 Figure 47 Fully Dimensioned Drawing . . . . . . . . . . . . . 60
Figure 10 Positioning a Prim . . . . . . . . . . . . . . . . . . . .17 Figure 48 Result of Parameterizing . . . . . . . . . . . . . . . 61
Figure 11 Parametric Grid Lines . . . . . . . . . . . . . . . . . .18 Figure 49 Component to be Drawn . . . . . . . . . . . . . . . 64
Figure 12 Possible Parameterization . . . . . . . . . . . . . .19 Figure 50 Displaying the Grid . . . . . . . . . . . . . . . . . . . . 64
Figure 13 Avoiding Coincident Points . . . . . . . . . . . . . .19 Figure 51 Addition of First Chain Dimension . . . . . . . . 65
Figure 14 Coincident Points . . . . . . . . . . . . . . . . . . . . .20 Figure 52 Adding More Dimensions . . . . . . . . . . . . . . . 65
Figure 15 Collinear Points on the Same Grid Line . . . .20 Figure 53 Fully Dimensioned Component . . . . . . . . . . 66
Figure 16 Aim of Parameterization . . . . . . . . . . . . . . . .20 Figure 54 Complete Parametric Grid . . . . . . . . . . . . . . 66
Figure 17 Example of Parameterizing a Specific Case.21 Figure 55 Old Component With New Parameters . . . . 67
Figure 18 Example of an Ideal Master Drawing . . . . . .21 Figure 56 Parameterized Component . . . . . . . . . . . . . 67
Figure 19 2D Parametrics Tooltray . . . . . . . . . . . . . . . .23 Figure 57 Object to be Dimensioned . . . . . . . . . . . . . . 68
Figure 20 Grid Lines Generated By Reference Point . .27 Figure 58 Displaying the Grid . . . . . . . . . . . . . . . . . . . . 69
Figure 21 Extra Grid Intersection Generated by Dimen- Figure 59 Detail Showing Fillet Grid Lines . . . . . . . . . . 69
sioning Line AB . . . . . . . . . . . . . . . . . . . . . . .27 Figure 60 Object With Angular Notch . . . . . . . . . . . . . . 71
Figure 22 Grid Completed by Second Dimension. . . . .28 Figure 61 Result of drawing the grid. . . . . . . . . . . . . . . 71
Figure 23 Toolset for Tolerance Settings . . . . . . . . . . .29 Figure 62 Adding a Line . . . . . . . . . . . . . . . . . . . . . . . . 72
Figure 24 Dialog for Placing Tolerance Setting Texts. .29 Figure 63 Dimensioned Angle With Grid . . . . . . . . . . . 72
Figure 25 Dialog for Tolerance Settings . . . . . . . . . . . .30 Figure 64 Dimensioning an Unsymmetrical Angle . . . . 73
Figure 26 A Linear Dimension. . . . . . . . . . . . . . . . . . . .32 Figure 65 Simplified Diagram of a Bicycle Chainset. . . 76
Figure 27 Object With Intersecting Baselines . . . . . . . .33 Figure 66 Dialog Parametric Point Function, activated 80
Figure 28 Chain Dimensioning With Center Support . .33 Figure 67 Object to be Parameterized . . . . . . . . . . . . . 81
Figure 29 Dialog for Filleting Settings . . . . . . . . . . . . . .34 Figure 68 Inferred Baselines . . . . . . . . . . . . . . . . . . . . 81
Figure 30 Examples of Under-Dimensioned Drawings .36 Figure 69 Object with New Set of Dimensions . . . . . . . 82
Figure 31 Examples of Over-dimensioned Drawings . .37 Figure 70 Object to be Parameterized . . . . . . . . . . . . . 83
Figure 32 Dialog for Changing Texts . . . . . . . . . . . . . .38 Figure 71 Displaying the grid . . . . . . . . . . . . . . . . . . . . 84
Figure 33 Toolset for Creating Viewboxes . . . . . . . . . .41 Figure 72 Inferred Baselines . . . . . . . . . . . . . . . . . . . . 84
Figure 34 Examples of Parametric Viewbox Shapes . .41 Figure 73 Object to be Parameterized . . . . . . . . . . . . . 86
Figure 35 Toolset for Creating Reference Points . . . . .43 Figure 74 Detail of Fillet Construction from Component in
Figure 36 Parametric Point Function. . . . . . . . . . . . . . .43 Figure 73 . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

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Figure 75 Displaying the grid . . . . . . . . . . . . . . . . . . . . 87 Figure 126 Symbol Loaded Using Teble Values From
Figure 76 Fully Dimensioned Drawing With Grid . . . . . 87 ROW2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 147
Figure 77 Fillet Detail from Figure 76 . . . . . . . . . . . . . 88 Figure 127 Toolset for CPI Named Groups . . . . . . . . 148
Figure 78 Dynamic Baselines . . . . . . . . . . . . . . . . . . . 88 Figure 128 Example for a CPI named group . . . . . . . . 149
Figure 79 After Parameterization . . . . . . . . . . . . . . . . . 89 Figure 129 Dimensioned Component . . . . . . . . . . . . . 150
Figure 80 Use of Variables in Joist Definition . . . . . . . 92 Figure 130 Changing Dimensions to Variables . . . . . . 151
Figure 81 Result of Changing Joist Dimension Variables Figure 131 Marking Positions of Tabs . . . . . . . . . . . . . 151
93 Figure 132 Dimensioned Tab . . . . . . . . . . . . . . . . . . . 152
Figure 82 Dimensioned Drawing . . . . . . . . . . . . . . . . . 95 Figure 133 Individual Points on the Fillets. . . . . . . . . . 153
Figure 83 Replacing Dimension Texts With Variables . 95 Figure 134 Tab Prepared for Saving . . . . . . . . . . . . . . 153
Figure 84 Example of In-sheet Commands . . . . . . . . . 97 Figure 135 CPI named Groups in Position . . . . . . . . . 154
Figure 85 Dialog for Creating LCIS Variables . . . . . . . 98 Figure 136 Detail of CPI named Group . . . . . . . . . . . . 154
Figure 86 Dialog for Query LCIS Variables . . . . . . . . . 99 Figure 137 Dimensioning the Attachment Points . . . . 156
Figure 87 Dialog Administrate parametric variables . 100 Figure 138 Result of temporary parameterization . . . . 157
Figure 88 Add new parametric variable . . . . . . . . . . . 101 Figure 139 Alternative Parameterization . . . . . . . . . . . 158
Figure 89 Dialog Load and Update parametric variables. Figure 140 Structure of a Parametric Group . . . . . . . . 160
102 Figure 141 Parametric Group With Three PPG Prims. 161
Figure 90 In-sheet DEF Command . . . . . . . . . . . . . . 105 Figure 142 Toolset for Groups . . . . . . . . . . . . . . . . . . 162
Figure 91 Dialog Parametric Graphics Control . . . . . 111 Figure 143 Example of Preventing Parameterization with
Figure 92 Toolset for Switches. . . . . . . . . . . . . . . . . . 112 Group Line and Prim . . . . . . . . . . . . . . . . 162
Figure 93 Dialog Parametric Switches . . . . . . . . . . . . 112 Figure 144 Component with Bolts . . . . . . . . . . . . . . . . 163
Figure 94 Dialog Command Options . . . . . . . . . . . . . 113 Figure 145 Adding a Parametric Group Line . . . . . . . . 164
Figure 95 Collinear Points With PAR COL OFF. . . . . 114 Figure 146 Result of Parameterization . . . . . . . . . . . . 164
Figure 96 Collinear Points With PAR COL ON . . . . . 114 Figure 147 Prim Placed Inside Parametric Group . . . . 165
Figure 97 Effect of PAR CIR OFF . . . . . . . . . . . . . . . 115 Figure 148 Change of Dimensions after parameterization
Figure 98 Effect of PAR CIR ON . . . . . . . . . . . . . . . . 115 166
Figure 99 Original Geometry With New Parameters . 116 Figure 149 Dimensioned Component . . . . . . . . . . . . . 167
Figure 100 Original and Parameterized Versions . . . . 116 Figure 150 Change Made to Component . . . . . . . . . . 168
Figure 101 The Parts of a Table . . . . . . . . . . . . . . . . . 118 Figure 151 Creation of New Group and Addition of Group
Figure 102 The Structure of Table Elements . . . . . . . . 119 Line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
Figure 103 Toolset for Tables . . . . . . . . . . . . . . . . . . . 120 Figure 152 Addition of Parametric Group Line . . . . . . 169
Figure 104 Dialog for Defining Tables . . . . . . . . . . . . . 121 Figure 153 Parameterized Component . . . . . . . . . . . 169
Figure 105 Example of a Table with 4 entries/rows and 3 Figure 154 Parameterized Component . . . . . . . . . . . . 170
variables. . . . . . . . . . . . . . . . . . . . . . . . . . . 121 Figure 155 Bolt Hole With Parametric Group . . . . . . . 171
Figure 106 Table With Variables . . . . . . . . . . . . . . . . . 122 Figure 156 Rotating a Parametric Group. . . . . . . . . . . 171
Figure 107 Example of an In-sheet TBL Command. . . 125 Figure 157 Component With Bolt Holes . . . . . . . . . . . 172
Figure 108 Original Component . . . . . . . . . . . . . . . . . . 126 Figure 158 Detail of Bolt Hole from Figure 157 . . . . . . 172
Figure 109 Dimensioned Component With Grid . . . . . 126 Figure 159 Parametric Group Line . . . . . . . . . . . . . . . 173
Figure 110 Changing Dimension Values to Variables . 127 Figure 160 Parameterized Drawing. . . . . . . . . . . . . . . 173
Figure 111 Table of Variable Values . . . . . . . . . . . . . . 127 Figure 161 Adding More Prims . . . . . . . . . . . . . . . . . . 174
Figure 112 Table and in-sheet commands. . . . . . . . . . 128 Figure 162 Parameterized Drawing. . . . . . . . . . . . . . . 174
Figure 113 Effect of the temporary parameterization. . 129 Figure 163 Dialog Post-Parameterization . . . . . . . . . . 177
Figure 114 Dialog for Selecting a Table Variant . . . . . 131 Figure 164 Callbacks available for Post-Parameterization
Figure 115 Example for Variant Parameterization, Input . . 178
132 Figure 165 Message for missing primary datum prim . 178
Figure 116 Example for Variant Parameterization, Result . Figure 166 Example for an invalid parameter after entering
132 181
Figure 117 Attachment Points . . . . . . . . . . . . . . . . . . . 135 Figure 167 Example for an invalid parameter after running
Figure 118 Dialog for Loading Parametric Symbol . . . 138 callback . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
Figure 119 Example for Error Messages while Loading a Figure 168 ppcb_array_copy_angled . . . . . . . . . . . . . 182
Parametric Symbol . . . . . . . . . . . . . . . . . . 140 Figure 169 ppcb_array_copy. . . . . . . . . . . . . . . . . . . . 183
Figure 120 Popup while Loading Parametric Symbol . 141 Figure 170 ppcb_multi_copy . . . . . . . . . . . . . . . . . . . . 183
Figure 121 Symbol Definition . . . . . . . . . . . . . . . . . . . . 142 Figure 171 ppcb_copy_rotate_pcd . . . . . . . . . . . . . . . 184
Figure 122 Parametric Symbol Loaded Onto Sheet . . 143 Figure 172 ppcb_copy_and_mirror . . . . . . . . . . . . . . . 184
Figure 123 Table as Part of a Parametric Symbol . . . . 144 Figure 173 ppcb_copy_rotate . . . . . . . . . . . . . . . . . . . 185
Figure 124 Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145 Figure 174 Example: Parameter Settings in the Dialog
Figure 125 Dialog Select values from Table . . . . . . . . 146 Post-Parameterization. . . . . . . . . . . . . . . . 186

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Figure 175 Example: Before Parameterization . . . . . . .186 Figure 187 Result of Simulating a Rotation . . . . . . . . . 199
Figure 176 Example: After Parameterization . . . . . . . .187 Figure 188 Result of Repeated Parameterization . . . . 201
Figure 177 Example: After Running Post-Parameterization Figure 189 Adding Two Circles and Two Rods . . . . . . 202
187 Figure 190 Simulated Mechanical Movement . . . . . . . 203
Figure 178 Dialog for Running Mechanisms . . . . . . . .191 Figure 191 Example 3D Modelling, Hole . . . . . . . . . . . 207
Figure 179 Drawing to be Parameterized . . . . . . . . . . .193 Figure 192 Example 3D Modelling, Plate . . . . . . . . . . . 208
Figure 180 Settings for repeated parameterization. . . .194 Figure 193 Example 3D Modelling, Prepared for Parame-
Figure 181 Result of Repeated Parameterization . . . . .194 terization and Modelling . . . . . . . . . . . . . . . 210
Figure 182 Object Definition Drawing . . . . . . . . . . . . . .195 Figure 194 Example 3D Modelling, Possible Results. . 211
Figure 183 Settings for linear motion . . . . . . . . . . . . . .196 Figure 195 Parametric Design and MEDUSA Sheet Metal
Figure 184 Result of Simulating a Motion . . . . . . . . . . .196 Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . 212
Figure 185 Component Definition . . . . . . . . . . . . . . . . .197 Figure 196 Dialog Parametric Element Types . . . . . . . 216
Figure 186 Replaced angular dimension values by vari-
ables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .198

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List of Figures

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INDEX

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Numeric Creates a parametric table 121

2D Design System 206 Creates free parametric command text 113
2D Parametrics Tooltray 23 usage 96
3D Design System 206 Creates parametric command text 113
3D Modelling 207 Creates parametric symbol attachment text 135
Creates parametric tolerance text 29
Creates parametric viewbox lines 41
A Creates parametric viewboxes 41
access values from a table 124 Creates static baselines, tool 80
Arc Dimensions 34 Creates user LCIS variables 98
Arithmetic Operators 106 Creating
assigning Values to LCIS Variables 98 a parametric group 162
assigning Values to Variables Using in-sheet commands 96 a table 120
Attachment Points 134 a Viewbox 41
avoid coincident points 19 an Instance Group 148
CPI Named Groups (example) 154
Families of Parts 11
B Parametric Symbols 134
Baseline Point Functions 78 post-parametric definition sheets 180
baselines 78 Reference Points 43
draw dynamic - 80 Symbol Libraries 11
point functions 44 Variable Tolerances 31
Basic Parametric Elements 214 Viewboxes 41
building the Parametric Grid 46
buttons for running simulation 192
D
Datum Dimensioning 33
C DEF Command 105
Callbacks available for Post-Parameterization 178 default layers 108
callbacks distributed with the 2D Parametrics module 182 DEL 109
Center Support 32 Deletable 109
Change selected dimension text, tool 38 delete error messages 52
changing layer properties 110 Deleting Elements During Parameterization 129
Circle Dimensions 34 deleting grid lines 47
Coincident Points 19 Deleting Inferred, Dynamic Baselines 77
collinear points 20 demo sheet
Command Options 113 post-parametric - 188
command texts 112 Dialog
Composite Drawing 204 Administrate parametric variables 100
constraints for Changing Texts 38
explicitly specified 80 Load and Update parametric variables 102
Coordinate Dimensioning 33 dialog
CPI named group 148 Command Options 113
CPI Named Groups Filleting Settings 34
toolset 148 for Defining Tables 121
create a dynamic baseline 80 for Loading Parametric Symbol 138

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A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

for Running Mechanisms 191 intersection and tangency constraints 86

for Selecting a Table Variant 131 load parametric symbol with table 144
Parametric Element Types 216 Object With Angular Notch 71
Parametric Graphics Control 111 of a table producing three parameterized versions of an
Parametric Point Function 43 object 126
Parametric Switches 112 of a Table with 4 entries/rows and 3 variables 121
Post-Parametrization 177 of an in-sheet TBL command 125
Query LCIS Variables 99 of Preventing Parameterization with Group Line and
Tolerance Settings 30 Prim 162
Dimension Text Change 38 parameterize a rectangle using a prim 53
Dimension Types 26 parameterize a rectangle using intersecting baselines 57
dimension values parametric group 160
specifying how the system calculates new - 30 positioning a Prim 17
dimensioning 25 positioning Baselines 16
an Angle 72 post-parametrization 186
an Unsymmetrical Angle 73 Repeated Parameterization 193
Hints 37 replace dimension values with variables 95
Instance Groups (example) 155 Rotating Parametric Groups 171
over - 37 Simulating a Working Mechanism 202
Techniques 27 Simulating Linear Motion 195
under - 36 Simulating Rotary Motion 197
dimensions Simulation of the Movement of a Lift Arm Assembly 13
After Parameterization 49 Static Groups 163
and the Grid 18 Symbol Library 12
in Parametric Design 26 tangency constraints 83
Display Post Param Dialog, tool 177 three separate instances of one symbol 150
Display the current settings of the parametric line styles, Use of Variables in Joist Definition 92
tool 216 Using a Program to Simulate Motion 200
Displaying Inferred, Dynamic Baselines 77 example
Displays the current settings of the parametrics system 112 how to load a parametric symbol 142
Displays the current tolerance settings 29 In-sheet Commands 97
draw dynamic baselines 80 Examples
Drawing Grids, toolset 46 of Over-dimensioned Drawings 37
Dynamic Baselines of Parametric Viewbox Shapes 14
delete 77 of Under-Dimensioned Drawings 36
display 77 simple parameterization 63
draw 80 Expressions 93
Dynamic Group usage 105
with One Prim 165
with Three Prims 172
with Two Prims 167 F
fillet dimensions
set automatically 34
E Fillet Grid Lines in detail 69
elements in parametric group 160 Filleting Settings 34
elements of a table 119 fillets 68
Enter Your Own Parameters 49 free parametric command text 113
error messages 51, 217
delete 52
while using variables 104 G
examining the Parametric Grid 48 Geometric Constraints
Example what are - 76
2D parametrics and 3D 207 Geometric properties 21
Chain Dimensioning With Center Support 33 geometric tolerance 18
constraints inferred by the system 81 Getting Started 39
dimensioning 27 grid
dynamic Group with One Prim 165 building parametric - 46
Dynamic Group with Three Prims 172 deleting - lines 47
Dynamic Group with Two Prims 167 examine parametric - 48
Family of Parts 11 parametric 17
for a CPI named group 149 when to draw? 47
how to deal with fillets 68 grid lines 18
In-sheet DEF Command 105 looking at 18

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A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

grid tolerance 18 Parametric Design

Group Elements 215 and 3D Modelling 207
Groups and MEDUSA Applications 206
toolset 162 what it is used for 10
Parametric Element Types 216
Parametric Elements Control 111
H Parametric Grid 17
HIT 109 Parametric Group
Hittable 109 create 162
Horizontal and vertical dimensions 32 Elements 160
Parametric Point Function 43
I Parametric Switches 112
Parametric Symbols
Inferred Constraints 77 creating 134
In-sheet Error Message Elements 215 load 138
Instance Group creation 148 save 142
INVIS 109 With Tables 144
Invisible 109 Parametric Symbols and tables 122
Parts of a table 118
L place for a reference point 16
LAY Command 110 point functions at the ends of baselines 44
Layer Conventions 108 Point Functions for baselines 78
Layer Properties 108 Popup while Loading Parametric Symbol 141
changing 110 postparam.she 188
LCIS Variable 98 Post-Parametric demo sheet 188
Linear dimensions 32 post-parametric module
Load parametric symbol 135, 138 purpose 176
procedure 139 Post-Parametrization dialog 177
load parametric symbol ppcb_array_copy 183
mistakes 140 ppcb_array_copy_angled 182
Loading Parametric Symbol ppcb_copy_and_mirror 184
popup menu 141 ppcb_copy_rotate 185
Logical Operators 106 ppcb_copy_rotate_pcd 184
Prefix Texts 49
prepare a drawing for parameterization by dimensioning 25
M prim of type PVG 15
MEDUSA Applications 206 print screen 204
Mistakes When Loading Symbols 140 Printing documentation from Portable Document Format
(PDF) files 8
PRO 109
N Procedure for creating post-parametric definitions 180
NC Definitions 206 procedure for simple parameterization of a part 40
Program to Simulate Motion, example 200
Protected 109
O PVG prim 15
object
parameterize 50
orthogonal view prim 16 Q
Over-dimensioning 37 Query LCIS Variables 99
overview
simple parameterization of a part 40
R
Radius Dimensions 95
P reconfiguring the Geometry of a Part 10
PAR BAS Switch 79 reference point 15, 43
PAR BAS switch 115 positioning 16
PAR CIR switch 115 Repeated Parameterization 190
PAR COL switch 114 Repeated Parameterization (Example) 193
PAR UND switch 116 rotating 21
PAR VAR 30 Rotating Parametric Groups 171
Parallel and perpendicular dimensions 32 Rules for Creating Variable Names 94
Parameterize the Master Drawing 22 running simulation buttons 192
parameterizing an Object 50

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A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

S arc 68
Screen Dump 204 Creates a parametric table 121
Selects a variant from a table and parameterizes it, tool 131 Creates free parametric command text 113
Selects elements or groups at sheet level, tool 136 usage 96
Sets options for fillet behavior during parameterization 34 Creates parametric command text 113
Sheet Metal Design System 206 Creates parametric symbol attachment text 135
Simple Parameterization Examples 63 Creates parametric tolerance text 29
simulate the movement of a mechanism, introduction 190 Creates parametric viewbox lines 41
Simulates mechanism motion, tool 191 Creates parametric viewboxes 41
Simulating Creates static baselines 80
a Working Mechanism (example) 202 Creates user LCIS variables 98
Mechanical Movement, overview 12 Display Post Param Dialog 177
Rotary Motion (example) 197 Display the current settings of the parametric line
summary 190 styles 216
Simulating Linear Motion, example 195 Displays the current settings of the parametrics
Special Cases 22 system 112
Special Drafting Techniques 18 Displays the current tolerance settings 29
specifying constraints explicitly 80 Draws baselines inferred when the baseline switch is
specifying how the system calculates new dimension on 77
values 30 Load parametric symbol 135, 138
Static Baselines 78 Parameterizes the geometry 50
static baselines 15 Parameterizes the geometry then immediately undoes 50
Static Groups, example 163 Selects a variant from a table and parameterizes it 131
structure of a table 118 Selects elements or groups at sheet level 136
Suffix Texts 49 Sets options for fillet behavior during parameterization 34
summary Simulates mechanism motion 50, 191
simulation 190 toolset
switches 112 Creating Reference Points 43
PAR BAS 115 Creating Viewboxes 41
PAR CIR 115 Drawing Grids 46
PAR COL 114 for CPI Named Groups 148
PAR UND 116 for Groups 162
Symbol for Parameterizing 50
preparation 135 for Tables 120
Symbol Elements 215 parametric switches and command texts 112
Symbol Libraries tooltray 23
creating 11 Transformable 109
Symbol with Table 136 TRN 109
Symbols
load - Using CPI NamedGroups 148 U
symbols UNDEL 109
mistakes when loading 140 Undeletable 109
Under-dimensioning 36
T UNHIT 109
Table Unhittable 109
accessing values from a - 124 UNPRO 109
creating 120 Unprotected 109
Elements 119, 215 Untransformable 109
structure 118 Untransformable Layers 123
Use With Parametric Symbols 136 UNTRN 109
Values 122
where to place 123 V
tables values
and Parametric Symbols 122 access - from a table 124
Variables and Expressions 122 values in tables 122
tangential arcs 68 Variable Tolerances
TBL Command 124 how to create 31
Tolerance Settings 30 Variables
tool save within sheet 100
Control Parametric Elements 111 variables 92
Convert the selected circular arc into a tangent point assign values to - Using in-sheet commands 96

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assign values to LCIS - 98 W

rules for - names 94 Warning Messages 217
Variables and Expressions in Tables 122 When to Draw the Grid 47
Variant 131 where to place a table? 123
vertical dimensions 32 Why Use in-sheet Commands? 96
viewbox 14 workflow
create 41 parameterize a rectangle using a prim 53
VIS 109 parameterize a rectangle using intersecting baselines 57
Visible 109

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