2. 2
Unit
Visualizing Shapes

3. Objectives List the six principal views of an object.
Understand the basic principles of orthographic projection.
Identify first- and third-angle projection drawings.
Visualize three-dimensional objects from orthographic drawings.
Apply proper dimensioning for project views.
Draw a missing view of an object from two given views.

4. Multiview Drawing Uses three primary views Top view Front view
Right side view

5. Views in a Glass Box

6. Orthographic Projection
Shows an object’s shape by projecting two or more views at right angles to each other

7. Third-Angle Projection
Used in the United States and Canada

8. First-Angle Projection
Used internationally

9. Arrangement of Views
Third Angle
First Angle

10. Surface Representation
True size and shape
Lines and surfaces identical to lines and surfaces of the object
Foreshortened
Lines and surfaces reduced by elimination of depth

11. Visualizing Objects First, locate top, front, and right side views
Pay attention to forms created by projections
Understand the print completely
Careful reading helps avoid costly mistakes

12. Visualizing Objects (cont.)
Watch for objects with identical top and right side views but different front views

13. Drawing Missing Views Find two of the three primary views
Top
Front
Right side
Each view has two required dimensions
Project the missing view from known dimensions