Section View

What is this object on the left?

An ugly rock?
Notice to the right the image shows that it is a more than that.
 Section View

What is a Section View?

A sectional view or a section looks inside an object. Sections are used to clarify
the interior construction of a part that cannot be clearly described by hidden lines
in exterior views. By taking an imaginary cut through the object and removing a
portion, the inside features may be seen more clearly.
 Section View
Creating a Section View.
1. The part is cut using an imaginary cutting plane.
2. The unwanted portion is mentally discarded exposing the interior construction.
Section View Example.

Remove
 Section View
Lines used in section views.
Cutting Plane: An imaginary plane along which a section is taken.
Cutting Plane Line: A line on a normal view that shows where the cutting plane
passes through the object.
 Section View
Lines used in section views.
Section Lines: Used to indicate
where the cutting plane cuts the
material. Section lines are thin
and the symbols (type of lines)
are chosen according to the
material of the object. Section
lines are generally drawn at a 45°
angle and they are generally
drawn 1/8” apart. However,
different materials (steel and
bronze) have different patterns
that may have a uniquely
different spacing.
 Section View
Lines used in section views.
Section Lines:
 Section View
Section Lining Symbols
 Section View
Lines used in section views.
Section Lining – Line Placement:
• Lines should never be parallel or
perpendicular to the object lines.
• If the outline of the object has 45
degree lines, 30 or 60 degree lines
should be used.
• Assemblies with several parts
should be lined with varying angle
section lines.
 Section View

Rules of Sectioning
Rule 1: A section lined area is always
completely bounded by a visible outline.
Rule 2: The section lines in all areas should
be parallel. Section lines shown in
opposite directions indicate a different part.
Rule 3: All the visible edges behind the
cutting plane should be shown.
Rule 4: Hidden features should be omitted
in all areas of a section view. Exceptions
include threads and broken out sections.
 Section View
What type of section should I use?
The type of section used depends on the situation and what information needs to
be conveyed.
Types of Sectional Views
1. Full Sections 6. Broken Out Sections
2. Half Sections 7. Removed Sections
3. Offset Sections 8. Assembly Sections
4. Aligned Sections 9. Conventional Breaks
5. Revolved Sections
 Section View
Full Section
To create a full section, the cutting plane passes fully through the object. Used in
many cases to avoid having to dimension hidden lines.
• In a full section, the cutting plane line passes fully through the part.
• Normally a view is replaced with the full section view.
• The section-lined areas are those portions that have been in actual contact
with the cutting-plane.
Section View
 Section View
Half Section
A half section exposes the interior of one half of an object while retaining the
exterior of the other half. Half sections are used mainly for symmetric objects or
assembly drawings. A centerline is used to separate the two halves. Hidden lines
should not be shown on either half.
Half Section Cutting Plane Line

• Half Section is used to the

exterior and interior of the
part in the same view.
• The cutting-plane line cuts
halfway through the part and
removes one quarter of the
material.
• The line that separates the
different types (interior and
Interior
exterior) may be a centerline
or a visible line.
Exterior
 Section View
Offset Section
An offset section is produced by bending the cutting plane to show features that
don’t lie in the same plane.
 Section View Cutting Plane Line

Offset Section
• Used to show parts and
features that do not line up
with each other.
• Cutting-plane line does not
travel in a straight line.
• The offsets or bends in the
cutting-plane line do not show
in the section.
• The versatility of this section
makes it very useful.
 Section View
Aligned Sections
Cutting Plane Line
• Usually used on symmetrical
circular parts.
• Place the cutting-plane line
to show the most detail.
• All parts and details are
rotated into the section
view.
• Ribs and spokes can be left
un-lined for better clarity in
the section view.
 Section View
Revolved Sections
• Used to show a small portion
of a drawing.
• Show a cross-section of an
area turned 90 degrees or
perpendicular to the object.
• Put into a drawing to show an
area not normally shown.
 Section View
Revolved Sections
 Section View
Broken-out Sections
• Used to generate a section for
a small area without using a
cutting-plane line.
• Removes a small amount of
material to show the interior
details.
• Always used in an
orthographic view.
• Used to enhance the
orthographic view by giving
the viewer a better look at key
interior details.
 Section View
Broken-out Sections
 Section View
Removed Section
• A removed section is
a section that is not
direct projection from
the view containing
the cutting plane – it
is located somewhere
else in the drawing.
 Section View
Assembly Sections
• Shows how parts fit together
• Allows better clarity with a
complicated assembly of
parts.
• Shows how parts not only fit
together, but allows for a
visual view of how they
function.
 Section View
Conventional Breaks
• To shorten a view of an elongated object, whether in section or not,
conventional breaks are recommended, as shown below.
 Section View
Exercise – 7: Below is the Isometric drawing of a component. Draw in the 3rd angle
projection the following views:
a) Front View
b) Sectional Plan View A – A
c) Right Side View