In article <399aa176@news.povray.org>, "dan" 
<dan### [at] snwpafbafmil> wrote:

> Explanation:  to generate realistic range images I need to create a Z 
> based pigment using the 'gradient' pigment modifier.

Why not just use the MegaPOV "depth" post_process filter?


> Question:   how do I force or modify gradient z so that it is valid 
> only from   0<Z<1 and gradient z = 0 otherwise?  If we can answer 
> this question, then creating random dot stereograms and producing 
> other such range imagery will become faster and more realistic using 
> povray.  My only alternative at this point is to clip the scene, 
> which causes a 10X increase in compute time.

You could use a function (in MegaPOV) specifying the blend you want, 
clipping it to the correct range. If your entire scene is to be 
contained within the range of the depth buffer, then you can simply 
scale the gradient up to fit the scene.

-- 
Christopher James Huff - Personal e-mail: chr### [at] maccom
TAG(Technical Assistance Group) e-mail: chr### [at] tagpovrayorg
Personal Web page: http://homepage.mac.com/chrishuff/
TAG Web page: http://tag.povray.org/

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