THE PLANE OF PROJECTION: The plane of projection is the imaginary
plane normally located between the observer and the object being drawn.
The location of the plane of projection determines the size of the object on
the picture plane. The points at which projectors intersect the picture plane
are called piercing points. A collective of all of the piercing points produces
perspective and are called perspectives.
THE PROJECTORS FROM THE OBSERVERS EYE TO ALL POINTS
ON THE OBJECT: The projectors are imaginary lines from the observers
eye to the object being drawn. Projectors are also called
range of view of visual rays is called the cone of vision.
Figure 5-4 shows piercing points and visual rays.
Figure 5-4.Piercing points, visual rays. and cone of vision.
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