Perspective, Continued
General
principles of
perspective
(Continued)
PICTURE PLANE (PP): The picture plane (PP) is the imaginary vertical
plane placed between the eye of the observer and the object being drawn.
Although the usual position of the picture plane is between the station point
and the object, you may also place the PP behind the object or behind the SP
as it is in photography when the image strikes the film or focal plane.
Moving the picture plane alters perspective or scale but not proportion. In
general, the farther the plane is from the object, the smaller the perspective.
A picture plane, plane of projection, and drawing surface may be the same.
Figure 5-6 shows possible locations for the picture plane.
Figure 5-6.—Location of the picture plane.
VANISHING POINT (VP): Vanishing points (VP) are where parallel
horizontal lines appear to converge.
Vanishing points are also known as the
center of vision (CV).
Figure 5-7 show how horizontal lines in perspective seem to converge into
vanishing points.
Figure 5-7.—Horizontal lines in
perspective.
Continued on next page
5-8
