SEEZ.IXP
A Public Domain IPAS routine
by Tom Hudson, for Yost Group, Inc.


SEEZ accesses the z-buffer inside of the 3D Studio R4 renderer through
the Video Post system so you can derive a bitmap from your scene that
represents the distance of objects from the camera.  

In order to use this IXP, you must add have the following statement
turned on in your 3DS.SET file:

        VPOST-ZBUFFER=ON
       
Setting this to ON (or YES) causes, when rendering in Video Post, a
zbuffer the full size of the screen to be allocated and computed
during rendering. This is 4 bytes per pixel-- 1.2 megs for a
640x480 rendering.  Since it uses so much memory, you probably
only want to turn it on when you absolutely need to use it.

Use SEEZ.IXP by putting it in your Video Post queue after a KFScene.
It will only work after a KFScene since it requires the 3D geometry
in the Video Post queue.  The bitmap that it writes will be an
8-bit gray-scale image that you can then use in other applications
that require z information.  

You can also use the z-buffer bitmap as a matte channel in another
Video Post sequence for creative distance-based compositing effects.
(eg, very useful for underwater scenes).

Note for IPAS developers:  The source code for SEEZ.IXP (SEEZ.C) is
also included in this archive file in order to demonstrate how to
access the zbuffer from your own IPAS routines.


[end]
