Graphics Programs Reference
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(a)
(b)
Figure 3.4: (a) Wrong and (b) Correct Perspective.
Exercise 3.1: Search the works of art (modern or otherwise) for examples of wrong or
reversed perspective.
Simply stated, sound perspective means that something seen happening in the fore-
ground of the shot must make a louder noise than something seen to be further away.
Most failures to respect the rule are instinctively heard as “bad sound,” as imperfect
or amateur use of recording technology.
—David Bellos, Jacques Tati (1999).
3.1 One Two Three ... Infinity
The first step toward understanding perspective is an understanding of converging lines
and vanishing points. Imagine a simple house shaped like a cube. If we stand in front
of it, we see only its front wall, a square, much like the one depicted in Figure 3.5a.
If, however, we imagine the house to be transparent, it would look like part (b) of the
figure. Its back wall is farther away from us, so it looks smaller than its front wall, which
is why the four parallel lines connecting the front and back walls do not look parallel;
they seem to converge to an imaginary point called a vanishing point . The vanishing
point exists only in our imagination, and we can imagine it only if we extend the four
lines in question. Thus, the vanishing point is a result of the way the brain interprets
what the eyes see.
We now walk around our transparent, cubic house and turn to the left, such that
our line of sight is aimed at one of the corners, as shown in Figure 3.5c. The house is
the same: it hasn't moved or changed shape. We, the viewers, are also the same, only
our position and orientation have changed. Yet, when we look at the house, we see two
groups of lines converging at two vanishing points (Figure 3.5d).
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