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From: peter@sugar.UUCP (Peter DaSilva)
Newsgroups: comp.graphics
Subject: Ray tracing and caustics.
Message-ID: <219@sugar.UUCP>
Date: Thu, 25-Jun-87 08:41:43 EDT
Article-I.D.: sugar.219
Posted: Thu Jun 25 08:41:43 1987
Date-Received: Sun, 12-Jul-87 10:52:42 EDT
Organization: Sugar Land UNIX - Houston, TX
Lines: 14
Keywords: ray-tracing caustics algorithm reality

I was looking at a beautiful ray-traced image not so long ago and wondering
why it looked less than real. There was something wrong with a transparent
object in it. I had to refer to a *real* transparent object to figure out
what it was: it had a nice diffuse shadow, but there was no caustic in and
around the shadow from the refraction of light rays from the light source.

It has occurred to me that I have never seen such an effect in ray-traced
images. It shouldn't be too hard: you would have to reverse ray-trace from
the light source for each transparent object and add the caustic to the
texture map for each matte object it eventually falls on. Has anyone
considered doing this?

If this does lead to any breakthroughs, would this be the first time a usenet
message was a reference in a technical paper :->?