POV-Ray : Newsgroups : povray.binaries.images : Radiosity and reflective glass : Re: Radiosity and reflective glass Server Time
18 Oct 2021 14:03:36 EDT (-0400)
  Re: Radiosity and reflective glass  
From: Samuel B 
Date: 15 Sep 2021 16:50:00
Message: <web.61425b4d75c5f925cb705ca46e741498@news.povray.org>
"Chris R" <car### [at] comcastnet> wrote:
> As promised, here is the scene with max_sample set to 10.  The artifacts are
> gone.  I also took the suggestion of using a 5x5 area light for the main indoor
> light.

Hi Chris,

It did help.

After reading the docs here
(http://www.povray.org/documentation/3.7.0/r3_4.html#r3_4_4_3_3_8) it would seem
that the max_sample feature controls the intensity of reflected/refracted rays.
It would appear that using it is similar to altering the brightness clamping of
reflected and refracted caustics in Blender Cycles... The bright blotches that
your scene was producing are probably analogous to the so-called "fireflies"
that you get in renderers such as Cycles. When you clamp these values, a scene's
lighting becomes a bit less realistic.

I can't think of any other good solution... You can't just add a no_radiosity
flag to the offending objects, because then the lighting would probably be
*really* unrealistic. And if you use a super-high count in the radiosity block,
the scene would take forever to render... The only other option I can think of
it to try Clipka's UberPOV to make use of the randomized radiosity samples (I
think the keyword to enable it is called no_cache). But even then, your problem
goes from blotches to sharp pixel-sized fireflies...

(For the record, I think most of the initial blotches you were seeing were cast
from the brass objects.)

Sam


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