2. Unit 5
Multiview Drawings

3. Learning Objectives Define spatial visualization.
Explain the relationship between an orthographic projection and a multiview drawing.
Identify and define the three dimensions of an object.
Define the six principal views and the three regular views.
Identify the three principal projection planes.

4. Learning Objectives
Explain three visualization principles for multiview drawings.
Identify the three types of flat surfaces.
Explain characteristics of cylindrical surfaces.
Explain characteristics of fillets, rounds, and runouts.
Identify differences between third-angle and first-angle projection.
Discuss computer-generated views.

5. The Role of Spatial Skills
Spatial visualization can be defined as the mental visualization of 2D and 3D shapes and objects, including such tasks as imagining objects in the mind as they are rotated, moved, or reflected in a mirror

6. Spatial Visualization Tools
Visualization of rotations
Answer: B

7. Spatial Visualization Tools
Mental rotation with two correct rotations
Answer: A and C

8. Spatial Visualization Tools
Surface development test
Answer: B

9. Spatial Visualization Tools
Mental visualization of folding and unfolding
Answer: D

10. Orthographic Projection
Created by projecting the points of a three-dimensional object onto a two-dimensional plane

11. Multiview Projection
Orthographic projection consisting of systematically arranged views to describe an object

12. Definition Summary
Orthographic projection, multiview projection, and multiview drawing are interchangeable terms
Represents the main type of drawing views used in industrial prints

13. Selection of Views Six principal views: Front Back Top Bottom
Right side
Left side

14. Selection of Views Three “regular” views commonly used in education:
Front
Top
Right side

15. Selection of Views

16. Dimensions of an Object
Height is how tall the object is, as measured on the front view
Width is how wide the object is, as measured on the front view
Depth is how deep the object is from front to back
Each dimension appears twice in the three regular views
“Length” and “breadth” are terms not used

17. Dimensions of an Object

18. Three Orientation Possibilities
Perpendicular
Parallel
Inclined

19. Three Projection Possibilities
Edge view
True size and shape
Foreshortened shape

20. Three Principal Planes of Projection
Frontal plane
Horizontal plane
Profile plane

21. Three Types of Flat Surfaces
Normal

22. Three Types of Flat Surfaces
Inclined

23. Three Types of Flat Surfaces
Oblique

24. Cylindrical and Curved Surfaces

25. Meanings of a Multiview Line
A—Edge view of a flat or curved surface
B—Intersection of two surfaces (just an edge)
C—Maximum contour of a curved surface

26. First-Angle and Third-Angle Projection
Dividing space into quadrants
Historical development of projection theory used two planes to divide space
After projections, the two planes are revolved into one, with quadrants two and four “collapsed”

27. First-Angle and Third-Angle Projection

28. Third-Angle Projection
Used in the United States

29. First-Angle Projection
Used in Europe

30. Computer-Generated Views
The benefits of creating views directly from the 3D model include:
Ease of construction
Ease of change
Accuracy in representing geometry
Intelligent association between the model and the annotations

31. Computer-Generated Views
Views created by the CAD program may need:
Individual line adjustment for weight or dash spacing
The representation of fillets, rounds, and runouts adjusted (see A versus B to the right)
Conventional practices reviewed

32. What do you see?
Print supplied by Sunnen Products Company.