P3D Re: Technical question: Missing dimension

[Larry Berlin <lberlin@xxxxxxxxx>]

>Date: Wed, 31 Mar 1999
>From: Gabriel Jacob <jacob@xxxxxxxxxxxxxx>
>..................
>Okay I know I should post this to T3D but I like to post to P3D,
>so here goes.
>ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø
>If two 2-D pictures equals 3-D, or 2D+2D=3D, how come it's not 4D?
>Where did the other dimension disappear to? Another dimension?
>Bruce, anyone? ;-)
>ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø?ø
>Gabriel
>

****  The answer is it isn't missing!

2D is represented by X and Y.

A second 2D picture is another X and Y.

A stereo pair used as a 3D image, develops the Z dimension out of
*differences in* the X dimension alone (|X1 - X2| = Z1). The Y dimension is
identically the same in both images. So Y1 = Y2 by definition and one of
them isn't getting lost, just duplicated as an abolute reference. There
would be no need to count the same identical factor twice.

If you do the same thing with two IDENTICAL 2D images, you have a situation
where X1 = X2 so that |X1 - X2| always = 0. This is a flat 2D image, or one
whose entire existence is confined to the stereo window plane which by
definition has Z = 0. You could say that a 2D image is X(something) x
Y(something) x Z(0) for all points in the image.

Larry Berlin

Email: lberlin@xxxxxxxxx
http://3dzine.simplenet.com/


------------------------------