# SECTION VIEWS Drawing and Sketching (Continued) Lecture 13B

## Presentation on theme: "SECTION VIEWS Drawing and Sketching (Continued) Lecture 13B"— Presentation transcript:

SECTION VIEWS Drawing and Sketching (Continued) Lecture 13B
Engineering Design GE121 SECTION VIEWS Drawing and Sketching (Continued) Lecture 13B

Sections Sections are views of surfaces exposed by cutting planes

Conic Section Different sections are created by varying the angle of the cutting plane. Circle Ellipse Parabola Hyperbola

Mechanical Drawing Section

Assembly Drawing

Construction Detail Sections

Topographic Maps

Topographic Sections

Topographic Sections (on Mars)

Wireframe Sections

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

Section Views in Engineering Sketches
Based upon the use of a cutting plane that cuts through the object to reveal interior surfaces Line of Sight Imaginary Cutting Plane

Section Views in Engineering Sketches

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

Section Views in Engineering Sketches
Ideally the objective is to eliminate all the hidden lines on the section, but it’s not always possible

Section Views in Engineering Sketches
Hidden lines used to avoid an additional view

Section Views in Engineering Sketches
Cutting 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

Section Views in Engineering Sketches
Bottom right sketch should be mirror image of that on the left.

Section Views in Engineering Sketches
This shows the kind of detail that goes into defining standard drawings. Two Cutting Plane Line - Formats

Section Views in Engineering Sketches
All 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)

Section Views in Engineering Sketches
Hatching symbol can be used to convey information about the material of the object.

Section Views in Engineering Sketches
More hatching symbols

Section Views in Engineering Sketches
Section lines are omitted around notes and dimensions

Section Views in Engineering Sketches
Full Section Cutting plane passes through the object in one continuous line

Section Views in Engineering Sketches
Half Section Cutting plane passes only half way through the object, then takes a 90° turn Generally for symmetrical objects

Section Views in Engineering Sketches
Hidden lines ideally omitted on both halves of the section view The sectioned and unsectioned portions are separated with a centreline Cutting plane uses one arrowhead only

Section Views in Engineering Sketches
Offset Section Cutting plane line which is bent at 90° angles at one or more locations in order to pass through important features

Section Views in Engineering Sketches

Section Views in Engineering Sketches
Change of angle of the cutting plane line is NOT shown in the section view

Section Views in Engineering Sketches
On multi-part assemblies, change the angle of hatching or hatching material symbol to identify different parts

Section Views in Engineering Sketches
Sketching and Drawing Sketching is a less-exact freehand operation, and straightedges are not generally used Drawing is more precise, and uses straightedges, and precise dimensions and angles

Activity: Sketch Section
Section View will replace Top View Start by reproducing the drawings shown here. Note that the End View lines up with the Front View. Adding the Top View may make it easier to visualize the Section View. Front View Right Side View

Activity: Sketch Section
Top View Front View

Activity: Sketch Isometrics
Sketch Isometric Views of the Objects in the previous examples as time permits