perspective drawings chapter 16. 2 technical drawing 13 th edition giesecke, mitchell, spencer, hill...

Perspective Drawings

Chapter 16

2Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart

© 2009 Pearson Education, Upper Saddle River, NJ 07458.

All Rights Reserved.

Objectives

• Identify a drawing created using perspective projection

• List the differences between perspective projection and axonometric projection

• Create a drawing using multiview perspective

3Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart

© 2009 Pearson Education, Upper Saddle River, NJ 07458.

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Objectives (cont.)

• Describe three types of perspective

• Measure distances in perspective projection

4Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart

© 2009 Pearson Education, Upper Saddle River, NJ 07458.

All Rights Reserved.

Understanding Perspectives• A perspective drawing involves

four main elements:• The observer’s eye• The object being viewed• The plane of projection• The projectors from the observer’s

eye to all points on the object

5Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart

© 2009 Pearson Education, Upper Saddle River, NJ 07458.

All Rights Reserved.

Understanding Perspectives• In perspective drawings, the plane

of projection, called the picture plane (PP), is placed between the observer and the object

• The position of the observer’s eye is called the station point (SP)

6Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart

© 2009 Pearson Education, Upper Saddle River, NJ 07458.

All Rights Reserved.

Understanding Perspectives• The ground line (GL) is the

intersection of the ground plane with the picture plane

• Parallel lines converge toward a single point on the horizon called the vanishing point (VP)

7Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart

© 2009 Pearson Education, Upper Saddle River, NJ 07458.

All Rights Reserved.

Understanding Perspectives

8Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart

© 2009 Pearson Education, Upper Saddle River, NJ 07458.

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Understanding Perspectives• Rules for perspective:

• All parallel lines that are not parallel to the picture plane vanish at a point

• If these lines are parallel to the ground, the vanishing point will be on the horizon

• Lines that are parallel to the picture plane remain parallel to one another and do not converge to a vanishing point

9Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart

© 2009 Pearson Education, Upper Saddle River, NJ 07458.

All Rights Reserved.

Perspective From a Multiview Projection

10Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart

© 2009 Pearson Education, Upper Saddle River, NJ 07458.

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Non-rotated Side View Method for Perspective

11Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart

© 2009 Pearson Education, Upper Saddle River, NJ 07458.

All Rights Reserved.

Position of the Station Point• The center line of the cone of visual

rays should be directed toward the approximate center of the object

• Draw the horizon in the perspective view at the same level above the ground line that you want to use as the height of the station point

12Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart

© 2009 Pearson Education, Upper Saddle River, NJ 07458.

All Rights Reserved.

Location of the Picture Plane• The picture plane can be placed:

• In front of the object• Behind the object• Behind the station point

13Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart

© 2009 Pearson Education, Upper Saddle River, NJ 07458.

All Rights Reserved.

Location of the Picture Plane

14Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart

© 2009 Pearson Education, Upper Saddle River, NJ 07458.

All Rights Reserved.

Three Types of Perspective

• Perspective drawings are classified according to their number of vanishing points:• One-point perspective (parallel

perspective)• Two-point perspective (angular

perspective)• Three-point perspective

15Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart

© 2009 Pearson Education, Upper Saddle River, NJ 07458.

All Rights Reserved.

One-point Perspective

16Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart

© 2009 Pearson Education, Upper Saddle River, NJ 07458.

All Rights Reserved.

Two-point Perspective

17Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart

© 2009 Pearson Education, Upper Saddle River, NJ 07458.

All Rights Reserved.

Three-point Perspective

18Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart

© 2009 Pearson Education, Upper Saddle River, NJ 07458.

All Rights Reserved.

Measurements in Perspective• All lines in the picture plane are

shown in their true lengths• All lines behind the picture plane

are foreshortened

19Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart

© 2009 Pearson Education, Upper Saddle River, NJ 07458.

All Rights Reserved.

Measurements in Perspective

20Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart

© 2009 Pearson Education, Upper Saddle River, NJ 07458.

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Vanishing Points of Inclined Lines

21Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart

© 2009 Pearson Education, Upper Saddle River, NJ 07458.

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Curves and Circles in Perspective

22Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart

© 2009 Pearson Education, Upper Saddle River, NJ 07458.

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Shading

• Shading pictorial drawings can be very effective in describing shapes of objects

23Technical Drawing 13th EditionGiesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart

© 2009 Pearson Education, Upper Saddle River, NJ 07458.

All Rights Reserved.

Computer Graphics

• Perspective drawings are the most time consuming types of pictorials to draw by hand

• CAD programs can produce wireframe or solid perspective representations• Users are typically able to select viewing

distance, focal point, z-axis convergence, and arc resolution scale