Alignment Overview

An alignment allows you to define your part's location and orientation in 3D space. It allows
your measuring machine to know where the part is located. A part without any alignment
has six degrees of freedom:

• Three degrees of rotation (about the X, Y, and Z axes)

• Three degrees of translation (origin in X, Y, and Z axes)

This diagram shows the six degrees of freedom in 3D space (x,y,z,u,v, and w)

Datum Reference Frame

A Datum Reference Frame (DRF) constrains the six degrees of freedom, fixing the part in 3D
space.

A part alignment represents the DRF specified on the drawing. The primary, secondary, and
tertiary datums define the DRF and identify the features to measure and use to create the
alignment.

• The three degrees of rotation are constrained by the I, J, K vector(s) of the datum
feature(s).

• The three degrees of translation are constrained by the X,Y,Z location(s) of the datum
feature(s).

LEVEL

Constrains two degrees of rotation such that the leveled axis matches the vector of the selected
feature.

This will always be the primary datum and must be a 3D feature with a vector.

Typical Features: Plane, Cylinder, Cone, or a constructed 3D feature.

ROTATE

Constrains one degree of rotation about the leveled axis such that the rotated axis matches the
vector of the selected feature.

This will always be the secondary or tertiary datum and must be a 2D or 3D feature with a
vector.

Typical Features: Plane, Line, Cylinder, Cone, or a constructed 2D/3D feature.

You can also select any two-point type features to simulate a line that can be used to rotate.
These can be two points, two circles, two spheres, or a combination thereof. The direction of
the simulated line is based on the order of the selected features.

ORIGIN

Constrains three degrees of translation (origin) in X, Y, and Z-axis.

This sets the origin on primary, secondary, and tertiary datums or as per drawing requirements.

Typical Features: Any feature.

Alignment Tips:

• LEVEL first, ROTATE second, and then set the ORIGIN for the X, Y, and Z axes. Never
Rotate before Leveling!

• Always LEVEL before measuring 2D features (lines and circles).

• Always LEVEL and ROTATE before measuring points (measured point in X, Y or Z-axis)

• There is no limit on the number of alignments saved in a measurement routine.

• You can use the SAVE ALIGNMENT command to save an alignment to a file. This is
typically done to create a fully automated measurement routine dependent on a holding
fixture for the part.
Program Folder Organization

1. Folder Structure

• Each program folder should include:

▪ A folder for CMM Reports

▪ A folder for Setup Instructions and/or Pictures

▪ The Program File itself

2. Saving CMM Reports

• Always save CMM reports in the CMM Reports folder that corresponds with the specific
part.
• Accurate and complete reports are essential for future reference.

3. Setup Instructions & Pictures

• Include any setup instructions or pictures in the designated folder.

• These resources help streamline the setup process when running the program.

4. Importance of Organization

• Keeping all files organized prevents delays and confusion.

• Failing to save reports or programs in the correct location can create problems later
when files are needed.
• Correctly saving programs ensures that when the part comes through the shop again,
time is not wasted searching for files or recreating programs.

5. Customer Requests

• Occasionally, a report may be requested by a customer for discrepancies, dimensional

verification, or record-keeping.
• Providing an accurate report is critical.
• If the report does not match the customer’s measurements, it could indicate either an
error on our end or a mistake by the customer.
PROGRAM WINDOW EXAMPLE
CMM REPORT FOLDER EXAMPLE
Creating an Alignment

1. Set Up the Workplane

o Ensure you are working in the correct workplane.

o Verify that all necessary features can be reached.

o Position the part so it is aligned with the center of the Romer arm and/or tracker.

2. Level the Part

o Identify the feature you will use to level (typically a plane or cylinder).

o Measure the feature using either Auto Feature or Measured Feature.

o Go to Insert > Alignment > New (or press Ctrl + Alt + A) to open the Alignment Utilities
dialog box.

o From the feature list, select the feature you just measured.

o Click Level to establish the orientation of the normal axis of the current workplane.

o Select the same feature again, then click the correct axis followed by Origin to move the
part origin to that location.

o Click OK to complete the level step.

3. Rotate the Part

o Measure the feature you will use for rotation (this may be a plane, two circles, a line, or
sometimes a cylinder).

o Open the Alignment Utilities again and repeat the level process.

o Select the feature ID of the rotation feature.

o Confirm that Rotate To is set to the correct vector directions.

o Click Rotate to align the defined axis of the workplane with the feature. PC-DMIS will
rotate around the centroid set as the origin.

o If the graphics view changes drastically (e.g., features no longer match or the trihedron
flips), this indicates an error.

o If the rotation feature will also be used to establish zero origin, select its feature ID,
choose the correct axis, and click Origin.

o Click OK when complete.

4. Set Zero Location

o Measure (or construct) the feature that will serve as the zero location using Auto
Feature, Measured Feature, or Constructed Feature.

o Open the Alignment Utilities and repeat the Level process, then the Rotate process.

o Select the zero feature’s ID.

o Choose the appropriate axis (or axes), then click Origin to move the part origin to the
center of that feature.

o Verify that the trihedron is fixed in place. If it shifts or rotates, an error has occurred.

o Ensure that the graphic display window matches the alignment.

 Workpiece Setup Considerations

When possible, aim to measure all relevant features in a single setup. This reduces the
risk of error and improves confidence in the results. Multiple setups may sometimes
be necessary—for example, when tighter tolerances or complex geometries require
them—but every additional setup increases both time and the chance for error. The
measurement strategy should balance speed and accuracy, always keeping the target
tolerance in mind.

Key Points:

• Minimize the number of setups.

• Use only one axis for critical dimensions whenever possible.
• Select the most appropriate machine for the job.
• Apply repositioning techniques when necessary.

Probe Techniques

Whenever possible, probe measurements should be taken perpendicular to the

workpiece surface. Coordinate measuring machines are designed to achieve the best
accuracy when the probe tip contacts the surface at, or very close to, a right angle.
Ideally, the probe should approach within ±20° of perpendicular to minimize error.
Avoid probe hits that are parallel to the stylus or angled against the probe body, as
these can introduce significant measurement errors.
 Mathematical Recommended
Geometric Feature
Minimum Minimum

LINE 2 3

PLANE 3 5

CIRCLE 3 5

CONE 6 12

CYLINDER 6 12

Probing points should be distributed to provide uniform coverage of the feature being
measured. This helps ensure that the data supplied to the software accurately
represents the geometry of the feature. During measurement, the operator should
continuously evaluate the results and remain aware of what is considered normal for
the chosen strategy. If results appear abnormal, they should be investigated
immediately to identify and correct any errors introduced at any stage of the process.
It is also good practice to keep records of all measurement program outputs and refer
to them when repeating measurement strategies.
3-2-1 Method

The 3-2-1 method, is a widely used technique for locating and constraining a workpiece during
measurement. The name comes from its three sequential steps: using three, then two, then
one point of known location. Together, these six points establish three mutually
perpendicular datums that fully define the workpiece position. When performing this method
correctly the part is completely constrained and ready for accurate measurement.

Step 1: First Feature (3 Points)

• Three points are required to define a plane. This is the "3" in 3-2-1.

• Real-world parts with tolerances will always rest on three points, even if more are
available.

• Example: A stool with three legs is stable; a four-legged stool often rocks.

• At this step, the part rests on three points, defining the primary datum plane.

Step 2: Second Feature (2 Points)

• Two points define a line on a feature perpendicular to the first. This is the "2."

• These two points create the secondary datum, further restricting movement.

Step 3: Third Feature (1 Point)

• One point defines the final constraint of freedom. This is the “1”

• This point forms the tertiary datum feature, locking the part completely in place.
TIPS

• Use the largest surface of the part for the first ("primary") reference plane.

• Position the three support points as far apart as possible.

• If more than three support points are required to prevent deflection, make the
additional points adjustable.

• It is best if the workpiece surfaces intended to contact the support points are
machined.

POTENTIAL CAUSES FOR CMM ERROR

• Accuracy of the CMM

• Environment in which the CMM is located
• Probing strategy used (operator)
• Characteristics of the workpiece

PC-DMIS Alignment Tips

• Even though PC-DMIS software takes care of the basic alignment it’s still a good idea to
line parts up “square” to the CMM axis to minimize algorithm error.

• If you are in doubt about the measurement, you can run the alignment twice to make
sure nothing has changed over a certain period of time. Running the repeat
verification can save time in the long run by ensuring accuracy and repeatability.

• Following the basics find three points to complete a full alignment example plane, line,
and point which satisfy the minimum requirements
o Plane on top 3 hits min Z axis
o Line on front 2 hits min Y axis
o Point on right or left X axis
Window Layouts Toolbar

Window Layouts toolbar

You can use the Window Layouts toolbar (View | Toolbars | Window Layouts) to store the layout of the
any open windows, editors, and toolbars. You can click on a stored layout to restore it in your current
measurement routine.

Layouts don't only store positions of toolbars and windows; they also store settings and options
associated with the windows and toolbars. If a layout has a certain setting selected, and you then save
that layout, the setting gets saved with the layout. If you later deselect that window setting, without
overwriting the stored layout, the next time you select the layout, PC-DMIS restores the saved setting.

This toolbar contains the following icons:

Minimize - This icon minimizes the Edit window’s size.

Maximize - This icon maximizes the Edit window’s size.

Save - This icon displays the Enter Window Layout Name dialog box that allows you to save the
current position and size of any open windows, editors, or toolbars under a desired layout name:

The Window Layout Name box specifies the name of the layout. PC-DMIS also displays this name as a
tooltip for the icon associated with the layout. If you don't include a layout name, PC-DMIS uses a
default name of "Recall Window Layout".

Once you click OK, the layout gets saved and an icon ( ) that represents that layout appears on the
toolbar with your layout configuration.

You cannot overwrite an existing layout with a new layout by giving it the same name. If you want to
overwrite an existing layout, first delete the existing layout, and then give it the same name.
 Restore Saved Layout - This icon restores the stored layout. Any windows, editors, and toolbars
are restored to their saved positions. Position your mouse pointer over the icon to show the name of the
stored layout.
Settings Toolbar

Settings toolbar

The Settings toolbar (View | Toolbars | Settings) contains lists that provide a more convenient
way to switch between the some settings. From left to right on the toolbar, these settings are:

A. Views - Saved views of the Graphic Display window

B. Alignments - Saved alignments

C. Probes - Defined probe types

D. Probe Tips - Defined probe tips and probe tip angles

E. Workplane - Available workplanes

F. Projection Planes - Planes (faces) to which to project certain features

Measured Features Toolbar

Measured Features toolbar

With the Measured Features toolbar (View | Toolbars | Measured Features), you can force PC-
DMIS to accept a given feature type, or you can have it guess and display the feature type for
which you are taking hits.

Point - Forces PC-DMIS to accept the Point feature type

Line - Forces PC-DMIS to accept the Line feature type

Plane - Forces PC-DMIS to accept the Plane feature type

Circle - Forces PC-DMIS to accept the Circle feature type

Round Slot - Forces PC-DMIS to accept the Round Slot feature type

Square Slot - Forces PC-DMIS to accept the Square Slot feature type

Cylinder - Forces PC-DMIS to accept the Cylinder feature type

Cone - Forces PC-DMIS to accept the Cone feature type

Sphere - Forces PC-DMIS to accept the Sphere feature type

Torus - Forces PC-DMIS to accept the Torus feature type

Set - Creates a Measured Set of features

 Guess - Enables a Guess Mode where the software guesses the feature type based on the
number of hits. PC-DMIS draws the guessed feature type in the Graphic Display window after
you take each hit.

Guess Mode Preview

PC-DMIS provides a visual preview of the feature type before you actually accept it. For
example, if you measure a cylinder, you need to take two sets of four hits, at two different levels
along the height of the pin. When you take four hits at the first level, PC-DMIS draws a circle in
the Graphic Display window. After you take the second level of hits, PC-DMIS displays two
circles, one on each level, that represents the measured cylinder.

The feature is only added to the measurement routine when you press the End key. You can
press the '-' or ALT + '-' keys to remove hits.

Forcing a Guessed Feature

If PC-DMIS displays the wrong feature type, you can click a specific feature icon to force PC-
DMIS to accept that feature. For example, if you select the Circle icon, PC-DMIS is forced to
accept the circle feature type as long as you take the minimum number of hits.
 Show CAD - Shows the CAD model.

Show GD&T - Shows your CAD model's embedded CAD GD&T callouts or PMI (Product
Manufacturing Information).

Show GD&T Notes - Shows your CAD model's embedded GD&T notes. You can only view these
embedded CAD elements. You cannot import them as commands into the Edit window.

Characteristics IDs - Shows the characteristic IDs for any CAD GD&T callouts. You can only see a
characteristic ID if its corresponding CAD GD&T is also visible (see Show GD&T above). For information
on characteristic IDs, see the "Showing or Hiding CAD GD&T Characteristic IDs" subtopic under the
"Working with CAD GD&T Callouts" topic in the "Editing the CAD Display" chapter.

Show Rotation Widget - Shows a small trihedron and cube in the bottom-left corner of each view
of the Graphic Display window. You can click on the cube to rotate the CAD model to a face. You can
double-click on the cube to both rotate and scale to fit the CAD model. For more information, see "Using
the Rotation Widget" in the "Editing the CAD Display" chapter.

Show Feature Label IDs - Shows the IDs for feature commands that you added to the
measurement routine.

Show Point Info Label IDs - Shows the label IDs for point information (Point Info) boxes.

Show DimInfo Label IDs - The label IDs for dimension info (DimInfo) boxes.

Show All Label IDs - Shows all the label IDs above.

Show All COPs - Shows all COPs and associated annotations.

Show All Meshes - Shows all Mesh features and associated annotations.
 Activate Colormaps - Shows or hides the active colormap in the Graphic Display window.

• For details on Pointcloud Colormap operators, see the "Pointcloud Operators" section of the PC-
DMIS Laser documentation.

• For details on the Mesh Colormap operator, see the "Creating a Mesh Operator" section of the
PC-DMIS Laser documentation.

Show All Cross Sections - Shows all measured and nominal Cross Sections, and associated
annotations.

Show Probe - Shows the animated probe's model.

Show Machine - Shows the animated machine's model. This option is available if you use PC-DMIS
in offline mode.

Show Probe Changer - Shows the animated probe changer's model.

Show Fixture - Shows any fixtures you've imported.

Show Clearance Plane - Shows any clearance planes you have defined.

Show ClearanceCube - Shows the ClearanceCube.

Dimension Toolbar

Dimension toolbar

The Dimension toolbar (View | Toolbars | Dimension) is used to quickly access the options
available from the Dimension menu. The icons for the dimensions below reference the "Using
Legacy Dimensions" chapter. If you want to use GD&T Feature Control Frames, see the "Using
Geometric Tolerances" chapter.

Location - See Location

Position - See Position

Distance - See Distance

Angle Between - See Angle Between

Concentricity - See Concentricity

Coaxiality - See Coaxiality

Circularity - See Circularity

Cylindricity - See Cylindricity

Straightness - See Straightness

Flatness - See Flatness

Perpendicularity - See Perpendicularity

Parallelism - See Parallelism

Total Runout - See Total Runout

Circular Runout - See Circular Runout

Surface Profile - See Surface Profile

Line Profile - See Line Profile

Angularity - See Angularity

Symmetry - See Symmetry

Size - See Size

Keyin - See Keyin

Constructed Features Toolbar

Constructed Features toolbar

From the Constructed Features toolbar (View | Toolbars | Constructed Features), you can use
icons to quickly access the feature construction options available from the Insert | Feature |
Constructed submenu.

Point - Constructs a point from inputs. For more information, see Point.

Line - Constructs a line from inputs. For more information, see Line.

Plane - Constructs a plane from inputs. For more information, see Plane.

Circle - Constructs a circle from inputs. For more information, see Circle.

Ellipse - Constructs an ellipse from inputs. For more information, see Ellipse.

Round Slot - Constructs a round slot from inputs. For more information, see Round Slot.

Square Slot - Constructs a square slot from inputs. For more information, see Square Slot.

Width - Constructs a width from inputs. For more information, see Width.

Curve - Constructs a curve from inputs. For more information, see Curve.

Cylinder - Constructs a cylinder from inputs. For more information, see Cylinder.

Cone - Constructs a cone from inputs. For more information, see Cone.

Sphere - Constructs a sphere from inputs. For more information, see Sphere.
 Surface - Constructs a surface from inputs. For more information, see Surface.

Feature Set - Constructs a feature set from inputs. For more information, see Feature Set.

Filter - Constructs a filter set from a scan, certain constructed features, or another filter
set. For more information, see Filter Set.

Adjusted Filter - Constructs an adjusted filter from adjusted scan data that was gathered
while scanning around sphere, cone, or cylinder features. For more information, see Adjusted
Filter.

Generic - Constructs a generic feature based on inputs but modified with expressions. For
more information, see Generic.
Auto Features Toolbar

Auto Features toolbar

With the Auto Features toolbar (View | Toolbars | Auto Features), you can access the same Auto
feature available on the various tabs of the Auto Features dialog box.

PC-DMIS determines which Auto features are enabled based on your PC-DMIS configuration and your
current probe type. For more information about what Auto features the different configurations support,
see "Inserting Auto Features" in the "Creating Auto Features" chapter.

The following icons are available:

Vector Point - Creates an Auto Vector Point feature from the surface vector at the clicked location.

Surface Point - Creates an Auto Surface Point feature at the clicked location.

Edge Point - Creates an Auto Edge Point feature on a line between two surfaces.

Angle Point - Creates an Auto Angle Point feature where three perpendicular surfaces meet.

Corner Point - Creates an Auto Corner Point feature where two lines or surfaces meet.

High Point - Creates an Auto High Point feature at the highest location on the surface.

Line - Creates an Auto Line feature on a line.

Plane - Creates an Auto Plane feature on a surface.

Circle -Creates an Auto Circle feature on a circle.

Ellipse - Creates an Auto Ellipse feature on an ellipse.

Round Slot - Creates an Auto Round Slot feature on a round slot.

 Square Slot - Creates an Auto Square Slot feature on a square slot.

Notch Slot -Creates an Auto Notch Slot feature on a three-sided square slot.

Flush and Gap - Creates an Auto Flush and Gap feature to measure the height difference between
two mating sheet metal parts. This becomes available with laser probes.

Polygon - Creates an Auto Polygon feature from a feature of three or more sides of equal length.

Profile 2D - Creates an Auto Profile 2D feature. This is available with vision probes.

Blob - Creates an Auto Blob feature. This is available with vision probes.

Cylinder - Creates an Auto Cylinder feature.

Cone - Creates an Auto Cone feature.

Sphere - Creates an Auto Sphere feature.

Alignment Overview

An alignment allows you to define your part's location and orientation in 3D space. It allows
your measuring machine to know where the part is located. A part without any alignment
has six degrees of freedom:

• Three degrees of rotation (about the X, Y, and Z axes)

• Three degrees of translation (origin in X, Y, and Z axes)

This diagram shows the six degrees of freedom in 3D space (x,y,z,u,v, and w)

Datum Reference Frame

A Datum Reference Frame (DRF) constrains the six degrees of freedom, fixing the part in 3D
space.

A part alignment represents the DRF specified on the drawing. The primary, secondary, and
tertiary datums define the DRF and identify the features to measure and use to create the
alignment.

• The three degrees of rotation are constrained by the I, J, K vector(s) of the datum
feature(s).

• The three degrees of translation are constrained by the X,Y,Z location(s) of the datum
feature(s).

LEVEL

Constrains two degrees of rotation such that the leveled axis matches the vector of the selected
feature.

This will always be the primary datum and must be a 3D feature with a vector.

Typical Features: Plane, Cylinder, Cone, or a constructed 3D feature.

ROTATE

Constrains one degree of rotation about the leveled axis such that the rotated axis matches the
vector of the selected feature.

This will always be the secondary or tertiary datum and must be a 2D or 3D feature with a
vector.

Typical Features: Plane, Line, Cylinder, Cone, or a constructed 2D/3D feature.

You can also select any two-point type features to simulate a line that can be used to rotate.
These can be two points, two circles, two spheres, or a combination thereof. The direction of
the simulated line is based on the order of the selected features.

ORIGIN

Constrains three degrees of translation (origin) in X, Y, and Z-axis.

This sets the origin on primary, secondary, and tertiary datums or as per drawing requirements.

Typical Features: Any feature.

Alignment Tips:

• LEVEL first, ROTATE second, and then set the ORIGIN for the X, Y, and Z axes. Never
Rotate before Leveling!

• Always LEVEL before measuring 2D features (lines and circles).

• Always LEVEL and ROTATE before measuring points (measured point in X, Y or Z-axis)

• There is no limit on the number of alignments saved in a measurement routine.

• You can use the SAVE ALIGNMENT command to save an alignment to a file. This is
typically done to create a fully automated measurement routine dependent on a holding
fixture for the part.
1. Launch PC-DMIS

• Locate the latest version of PC-DMIS on your desktop.

• Double-click to open the software.

• The main PC-DMIS window should appear.

2. Open the Template

• Click on the folder outlined in red labeled Open Routine.

• Inside this folder, you will find templates for both inches and millimeters.

• Select the template that matches the units shown on the part print.
3. Save the Template as a Program

• With the template open, go to File > Save As (top left corner).
• A folder window will appear. Verify you are in the correct directory (typically named
PCDMIS Programs [Year], where the year matches your software version).

4. Organize by Customer and Part

• Locate the customer folder for the part you are inspecting.
• If this is a new customer, create a new folder labeled with the customer/company name.
• Open the customer folder.
• Inside, create a folder labeled with the part number.
• Open the part number folder.

5. Save the Program

• Save your program in this folder.

• Rename the file using the part number followed by the current revision.
o Example: 12345_RevB
6. Final Setup

• At the top of the program window, locate the field labeled Part Number and enter the
part number.
• In the field directly below, labeled Rev Number, enter the current revision.
• Save the program.
• Once saved, you are ready to begin inspecting the part.