Perspective projection creates realistic views by placing the center of projection at a finite distance from the viewing plane. Objects appear smaller as their distance from the viewing plane increases. Parallel lines that do not align with the viewing plane converge at vanishing points, which represent points at infinity. The number of principal vanishing points, determined by the principal axes intersecting the view plane, can be one, two, or three depending on the orientation of the projection plane.

1. Perspective Projection

2. Perspective Projection

3. Perspective Projection
 In a perspective projection, the center of projection is
at a finite distance from the viewing plane.
 Produces realistic views but does not preserve
relative proportion of objects
 The size of a projection object is inversely
proportional to its distance from the viewing plane.

4. Perspective Projection
 Parallel lines that are not parallel to the
viewing
plane, converge to a vanishing point.
 A vanishing point is the projection of a point at
infinity.

5. Vanishing Points
 Each set of projected parallel lines will have a
separate vanishing points.
 There are infinity many general vanishing points.

6. Perspective Projection
 The vanishing point for any set of lines that are parallel to one of the
principal axes of an object is referred to as a principal vanishing point.
 We control the number of principal vanishing points (one, two, or three)
with the orientation of the projection plane.

7. Perspective Projection
 The number of principal vanishing
points in a projection is determined by
the number of principal axes
intersecting the view plane.

8. Perspective Projection
One Point Perspective
(z-axis vanishing point)

9. Perspective Projection
Two Point Perspective
(z, and x-axis vanishing points)
y
x
z
y
x
z

10. Perspective Projection
Two Point Perspective

11. Perspective Projection
Three Point Perspective
(z, x, and y-axis vanishing points)
y
x
z
y
x
z

12. Perspective Projection

13. Perspective Projection
Transformation

14. Summary