----- Original Message -----
From: "Don Cox" <[log in to unmask]>
> It is true that if you get the angle of view right, and shut one eye, a
> flat perspective image can look surprisingly real.
Like the effect of echoes on our location of sound sources...our brains
use a number of qualities of the images we see to establish what we
think of as "3-D!" This is why computer video images can be branded as
"3D"...in spite of the fact they are viewed as single images on a single
screen. This is also why we draw using "perspective" and also use shadows
as well as the relative position (what is "in front" of what and thus
blocks part of the image of the second item).
Keep in mind that all of those ideas were first presented by painters
(Dutch, IIRC) in the 16th century...and paintings all of a sudden looked
very much more "realistic!"
Steven C. Barr