Re: backward ray tracing

Phil Hobbs <pcdhSpamMeSenseless@xxxxxxxxxxxx> wrote in news:13rugujjvpubfd9
@corp.supernews.com:

Okay, so if I understand this correctly, the problem is not so much the
caustics themselves as it is the diffuse scattering surface that makes
them visible. To model the caustic with the same accuracy as the main
ray trace, you'd need as many rays per unit area on the diffuser as on
the eyeball, which could get expensive. To do it efficiently, you'd
need to trace forwards to get the caustic, and then trace backwards to
see what it looks like to the eye.

That's pretty much it.

If the the object casting the caustics is distant or small in the
scene, you can get away with a low resolution forward trace. But
if you have a closeup of the object is question (like my diamond)
then you need all the forward rays you can get or else the pattern
seen by the backwards rays will be pixelated.

I haven't played with POVRay in a while, so I think I'll try to
whip a demo of this if I can remember how.

In the mean time, if you want to see some amazing examples of
this totally open source programs capabilities, take a gander over
to http://www.povray.org/ and check out the Hall Of Fame gallery
on the right side.

Brian
--
http://www.skywise711.com - Lasers, Seismology, Astronomy, Skepticism
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Sed quis custodiet ipsos Custodes?
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