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GE 121 – Engineering Design - 2009
Engineering DesignGE121
SECTION VIEWSDrawing and Sketching
(Continued)
Lecture 13B
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GE 121 – Engineering Design - 2009
Sections
Sections are views of surfaces exposed by cutting planes
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GE 121 – Engineering Design - 2009
Conic Section
Different sections are created by varying the angle of the cutting plane.
Circle Ellipse Parabola Hyperbola
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GE 121 – Engineering Design - 2009
Mechanical Drawing Section
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GE 121 – Engineering Design - 2009
Assembly Drawing
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GE 121 – Engineering Design - 2009
Construction Detail Sections
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GE 121 – Engineering Design - 2009
Topographic Maps
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GE 121 – Engineering Design - 2009
Topographic Sections
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GE 121 – Engineering Design - 2009
Topographic Sections(on Mars)
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GE 121 – Engineering Design - 2009
Wireframe Sections
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GE 121 – Engineering Design - 2009
Section Views in Engineering Sketches
Improve clarity and reveal interior features of parts
Eliminate (or greatly reduce) hidden lines so sketches are more easily visualized and understood
The following section views images are taken from:Bertoline(1999): Introduction to Graphics for Engineers, McGraw-Hill
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GE 121 – Engineering Design - 2009
Section Views in Engineering SketchesBased upon the use of a cutting plane that cuts
through the object to reveal interior surfaces
Line of Sight Imaginary Cutting Plane
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GE 121 – Engineering Design - 2009
Section Views in Engineering Sketches
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GE 121 – Engineering Design - 2009
Section Views in Engineering Sketches
Normal Orthographic View Section View
Section View can replace one of the normal orthographic views, or it could be drawn as a separate view
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GE 121 – Engineering Design - 2009
Section Views in Engineering SketchesIdeally the objective is to eliminate all the hidden
lines on the section, but it’s not always possible
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GE 121 – Engineering Design - 2009
Section Views in Engineering Sketches
Hidden lines used to avoid an additional view
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GE 121 – Engineering Design - 2009
Section Views in Engineering SketchesCutting plane is indicated as an edge view in one of the
orthographic views (cutting plane line) Labeled Thick line (0.6mm), dashed line, which extends beyond the edge
of the object & terminates with arrowhead at 90° to the cutting plane
Two types of dashed lines Arrowheads indicate the direction of view or line of sight
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GE 121 – Engineering Design - 2009
Section Views in Engineering Sketches
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GE 121 – Engineering Design - 2009
Section Views in Engineering Sketches
Two Cutting Plane Line - Formats
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GE 121 – Engineering Design - 2009
Section Views in Engineering SketchesAll surfaces touched (cut) by the cutting plane are
marked with cross hatching or a special hatching symbol Generic hatch pattern is normally at 45° unless object edges
are at 45 (never want hatching to be parallel or perpendicular to object edges. If necessary, change angle of hatch to avoid this)
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GE 121 – Engineering Design - 2009
Section Views in Engineering Sketches
Hatching symbol can be used to convey information about the material of the object.
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GE 121 – Engineering Design - 2009
Section Views in Engineering Sketches
More hatching symbols
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GE 121 – Engineering Design - 2009
Section Views in Engineering Sketches
Section lines are omitted around notes and dimensions
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GE 121 – Engineering Design - 2009
Section Views in Engineering Sketches
Full SectionCutting plane passes through the object in one
continuous line
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GE 121 – Engineering Design - 2009
Section Views in Engineering SketchesHalf Section
Cutting plane passes only half way through the object, then takes a 90° turn
Generally for symmetrical objects
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GE 121 – Engineering Design - 2009
Section Views in Engineering SketchesHidden lines ideally omitted on both halves of the
section viewThe sectioned and unsectioned portions are
separated with a centrelineCutting plane uses one arrowhead only
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GE 121 – Engineering Design - 2009
Section Views in Engineering Sketches
Offset SectionCutting plane line which is bent at 90° angles at one
or more locations in order to pass through important features
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Section Views in Engineering Sketches
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GE 121 – Engineering Design - 2009
Section Views in Engineering SketchesChange of angle of the cutting plane line is NOT
shown in the section view
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Section Views in Engineering SketchesOn multi-part assemblies, change the angle of
hatching or hatching material symbol to identify different parts
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GE 121 – Engineering Design - 2009
Section Views in Engineering Sketches
Sketching and DrawingSketching is a less-exact freehand operation,
and straightedges are not generally usedDrawing is more precise, and uses
straightedges, and precise dimensions and angles
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GE 121 – Engineering Design - 2009
Activity: Sketch Section
Front View Right Side View
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Activity: Sketch Section
Top View
Front View
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GE 121 – Engineering Design - 2009
Activity: Sketch Isometrics
Sketch Isometric Views of the Objects in the previous examples as time permits
