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From: peter@sugar.UUCP (Peter da Silva)
Newsgroups: comp.graphics
Subject: Re: Ray tracing and caustics.
Message-ID: <413@sugar.UUCP>
Date: Sun, 19-Jul-87 14:26:53 EDT
Article-I.D.: sugar.413
Posted: Sun Jul 19 14:26:53 1987
Date-Received: Sun, 26-Jul-87 21:14:28 EDT
References: <219@sugar.UUCP> <543@saturn.ucsc.edu>
Organization: Sugar Land UNIX - Houston, TX
Lines: 12
Keywords: ray-tracing caustics algorithm reality
Summary: That sounds like an expensive method.

> > [i made the original comment about caustics]
> [an explanation of how someone did them, probably by taking a random
>  sample of vectors from any ray intersection with a matte surface]

I thought of that, but assumed that it would lead to too much overhead.
In most scenes you're not likely to get many caustics from non-reflective
or transparent objects, which is why I suggested doing a pre-trace pass
originating at the light source to paint the caustics on matte surfaces.
Not nearly as accurate a technique, but likely much faster. Of course I could
be completely wrong about the speed problem. It's been known to happen.
-- 
-- Peter da Silva `-_-' ...!seismo!soma!uhnix1!sugar!peter (I said, NO PHOTOS!)