Engineering H191 - Drafting / CAD
Section Views
Lecture 10
Autumn Quarter
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Lect 10
P. 1
Engineering H191 - Drafting / CAD
Topics For Today
• Sections Views
– Why section views are needed
– Types of section views
– References
• TG Chapter 5
• QUIZ – Wednesday/Thursday – Sections
• Lab 3 – Thursday/Wednesday – Springs & Levers
– Read the lab notes and procedures before
coming to lab
Autumn Quarter
Gateway Engineering Education Coalition
Lect 10
P. 2
Engineering H191 - Drafting / CAD
Section Views
• Goals
– Recognize various kinds of section views,
make full and half section views.
– Improve visualization of interior features.
Autumn Quarter
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Lect 10
P. 3
Engineering H191 - Drafting / CAD
Section Views
Section views are used when
important hidden details are in the
interior of an object.
These details appear as hidden lines
in one of the orthographic principal
views; therefore, their shapes are
not very well described by pure
orthographic projection.
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P. 4
Engineering H191 - Drafting / CAD
Types Of Section Views
•
•
•
•
•
•
Full sections
Half sections
Offset sections
Revolved sections
Removed sections
Broken-out sections
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P. 5
Engineering H191 - Drafting / CAD
Cutting Plane
• Section views show how an object would look if a
cutting plane (or saw) cut through the object and
the material in front of the cutting plane was
discarded
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Engineering H191 - Drafting / CAD
Cutting Plane Line
• Precedence of Lines
Center Line
Hidden Line
Object Line
Cutting Plane
Line
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Engineering H191 - Drafting / CAD
Section Lines
•
Section lines (crosshatching) are used to show
where the cutting plane passed through solid
material
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Engineering H191 - Drafting / CAD
Full Section View
• In a full section view, the cutting plane cuts
across the entire object
• Note that hidden lines become visible in a section
view
Hidden Lines
are Visible
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Lect 10
P. 9
Engineering H191 - Drafting / CAD
Full Section View
•Shows cutting plane in the top view
•Makes a full section on the front view
Autumn Quarter
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Lect 10
P. 10
Engineering H191 - Drafting / CAD
Full Section View
•Note how the cutting plane is
drawn and how the
crosshatching lines mark the
surfaces of material cut by the
cutting plane.
•No hidden lines on the section
view, if possible.
•Note: Interior lines behind
cutting plane became visible.
Visible lines
omitted
Incorrect
Correct
Autumn Quarter
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Lect 10
P. 11
Engineering H191 - Drafting / CAD
Multiple Sectioned Views
SECTION A-A
B
A
SECTION B-B
Autumn Quarter
A
B
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Lect 10
P. 12
Engineering H191 - Drafting / CAD
Half Section View
The cutting planes do not cut all the way through to
the object. They cut only half way. They intersect at
the centerline.
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P. 13
Engineering H191 - Drafting / CAD
Half Section View
• Half Section used
mainly for symmetric
objects
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Lect 10
P. 14
Engineering H191 - Drafting / CAD
Revolved Sections
• Revolved
sections
examples show
the shape of an
object’s crosssection
superimposed on
a longitudinal
view
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P. 15
Engineering H191 - Drafting / CAD
Removed Sections
Removed sections are
like revolved sections
but moved aside.
Note how they are
named.
A
Section B-B
A
Section A-A
B
B
Section C-C C
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Engineering H191 - Drafting / CAD
Broken Out Sections
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Lect 10
P. 17
Engineering H191 - Drafting / CAD
Offset Sections
Offset sections are used to show interior features that
do not lie along a straight line
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P. 18
Engineering H191 - Drafting / CAD
Offset Sections
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Lect 10
P. 19
Engineering H191 - Drafting / CAD
Conventional Revolutions
• Used to make section views clear and avoid
confusion
• Associated with objects that have holes, ribs,
spokes, or lugs in any combination equally
spaced in a circular fashion
• Not projected orthographically to section view
• Examples to follow
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P. 20
Engineering H191 - Drafting / CAD
Conventional Hole Revolutions
• Note no hidden lines
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Engineering H191 - Drafting / CAD
Conventional Rib Revolutions
• Note: Ribs not crosshatched
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P. 22
Engineering H191 - Drafting / CAD
Conventional Spoke Revolution
• Note: Spokes not crosshatched
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Lect 10
P. 23
Engineering H191 - Drafting / CAD
Holes and Ribs in Combination
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Lect 10
P. 24