cadman wrote:
> 
> Where can I find the docs for Mr. Wilson's dispersion patch?  All my
> searches turn up 404'd.

  About the only thing I know exsists as far as documentation is the
little bit that Mike Hough provided with his windows compile of it.
The usage portion of the tiny text file is below:


------------
  The new dispersion feature creates a prismatic color effect in
refractive objects. It does this by refracting different colors
(wavelengths) differently within the object interior.  There are
two new keywords to control the effect.  They should be placed in
interior.

dispersion float - 

   Controls the amount of dispersion to be used.  A value of 1 is
no dispersion. Values around 1.1 or 1.2 seem to work well in most
situations.

disp_nelems integer -

  Specifies how many different colors should be used to samples the
disperion. The default is 7, but higher values are really needed to
get a good result. At around 50 disp_nelems the colors start to look
more accurate and at 100 it looks very smooth at normal resolutions.

  In this compile there is no way to turn the dispersion off and images
can suffer as a result unless the disp_nelems is set to a high value,
even when dispersion is set to one.  It manifests itself as a yellowing
hue on refractive objects.  I recommend using the official version of
POV-Ray when the dispersion feature is not wanted.  Another thing to
look out for is an odd bug that causes the dispersion to disappear if
the render is interupted.  I suppose the positive thing that can be
gleaned from this is that it gets around the previously mentioned problem. :)

I suppose that covers the important stuff.


-- 
Ken Tyler

mailto://tylereng@pacbell.net

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