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Chapter 4 Perspective, Scene Design, and Basic Animation
A
vanishing point
is the point in the background where edges of all assets
will meet at a single point if extended. A rectangular surface will appear
pinched into more of a triangular shape. In other words, parallel lines do not
appear parallel. Notice how the road in Figure 4-25A appears to narrow and
darken as it recedes into the background. In the far distance, the road vanishes
to a single point. In Figure 4-25B, you can better see the vanishing point. By
blocking out the background images, you can see the road appears to form a
triangle. The farthest point in the distance—the vanishing point—is the top of
the triangle. Of course, the edges of the actual road remain parallel, they just
appear to meet in the distance.
If you look more closely at the picture, you will also see that the
treetops and all other “north/south” objects vanish to the same point. In
Figure 4-25C, red lines are added to the trees where the trunk meets the
branches and to the road edges. You can clearly see all objects recede to the
same vanishing point. In this case, the vanishing point is centered in the
middle of the view. This scene is now divided into four triangles of visual
perception.
A 3D game engine will create
an object using a vanishing point
in the center of the screen if the
view is first person. If the view is
third person, then the vanishing
point will be at the midpoint of
where the camera is pointed. To
achieve a vanishing point, the
3D engine uses the concept of
pixel shading and
vertices.
CHEAT CODE: VERTICES
While some consider the plural of
vertex to be vertexes, it is actually
vertices (ver-ti-sees). A group of
more than one vertex is a group of
vertices.
Figure 4-25.
Goodheart-Willcox Publisher; image: Shutterstock.com
A—The vanishing point is clearly visible in this photo. It is in the middle of the image.
B—If the trees and sky are blacked out, the point where the edges of the road converge
is obvious. C—Red lines are added to show the receding lines on the road and trees. The
receding lines converge at the vanishing point.