Perspective Drawings Chapter 16

2 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ 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

3 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Objectives (cont.) Describe three types of perspective Measure distances in perspective projection

4 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ 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

5 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ 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)

6 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ 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)

7 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Understanding Perspectives

8 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. 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

9 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Perspective From a Multiview Projection

10 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Non-rotated Side View Method for Perspective

11 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ 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

12 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ 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

13 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Location of the Picture Plane

14 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ 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

15 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. One-point Perspective

16 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Two-point Perspective

17 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Three-point Perspective

18 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ 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

19 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Measurements in Perspective

20 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Vanishing Points of Inclined Lines

21 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Curves and Circles in Perspective

22 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ All Rights Reserved. Shading Shading pictorial drawings can be very effective in describing shapes of objects

23 Technical Drawing 13 th Edition Giesecke, Mitchell, Spencer, Hill Dygdon, Novak, Lockhart © 2009 Pearson Education, Upper Saddle River, NJ 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