POV-Ray : Newsgroups : povray.advanced-users : How to create realistic caustics? : Re: How to create realistic caustics? Server Time
24 Mar 2023 12:23:41 EDT (-0400)
  Re: How to create realistic caustics?  
From: Juergen
Date: 11 Mar 2022 17:35:00
Message: <web.622bcd6ba728bcefa6f2d031df9b2273@news.povray.org>

I have been looking into the topic of caustics once again. Starting from a scene
that I found on the Internet, I have adapted for a need and have come after some
trying also to a useful result (1.Appendix "Photons..."). However, setting the
photon parameters is quite difficult until you get a good result. Especially you
have to override the number of photons (in my case with "spacing").
But still the problem with the needed computing time remains. The example in the
attachment takes about 100sec to calculate, my later scene, where I want to use
this, *over 10 hours*, where 99% goes for the photon calculation and the actual
render takes about 5 min. (And saving the photons is not possible, because this
is to be used later in an animation).

Therefore I have tried other variants:
1. cautics from Povray itself: here I got a "nice" result
2. a superimposed texture: you can forget it, it looks like crap in all
3. simulation via a second, covered bright light source. A light source is
simply surrounded by a partially transparent sphere to achieve the corresponding
effects. Hereby I achieved the best result so far (attachment "lightsource...").
The problem here is that first the complete scene is covered with the texture.
If there are also areas in the picture that are outside the water, the light
source must be blocked additionally, so that these areas are not illuminated.
Furthermore, the cast shadows are just as sharp as with any other light source,
but I think you can live with that.

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