1. Perspective drawings are classified according to their number of ground lines.
2. All parallel lines that are not parallel to the picture plane vanish at a point.
3. All lines in the picture plane are shown in their true lengths.
4. Lines that are parallel to the picture plane remain parallel to one another and do not converge to a vanishing point.
5. Shading pictorial drawings may lead to confusion when describing shapes of objects.
6. Perspective drawings are the least time-consuming types of pictorials to draw by hand.
7. The horizon in the perspective view should be drawn at the same level above the ground line as the height of the station point.
8. Only vertical lines behind the picture plane are foreshortened.
9. Parallel lines converge toward a single point on the horizon called the vanishing point.
10. Most CAD programs produce only wireframe, not solid perspective representations.
11. The vanishing point is the intersection of the ground plane with the picture plane.
12. Using CAD, you are typically able to select viewing distance, focal point, z-axis convergence, and arc resolution scale for perspective representations.
13. The picture plane should never be placed behind the station point.
14. The position of the observer's eye is called the station point.
15. The picture plane can be placed either behind the object or in front of the object.
16. One-point perspective is also known as angular perspective.
17. Two-point perspective is also known as:
18. This is the intersection of the ground plane with the picture plane:
19. When positioning this feature of perspective projection, the centerline of the cone of visual rays should be directed toward the approximate center of the object:
20. Perspective drawings are classified according to their number of these features: