POV-Ray : Newsgroups : povray.binaries.images : Impending Disaster : Re: Impending Disaster Server Time
5 Jul 2022 23:59:08 EDT (-0400)
  Re: Impending Disaster  
From: Kenneth
Date: 1 Feb 2022 14:55:00
Message: <web.61f98ecd941abfdd4cef624e6e066e29@news.povray.org>
"Chris R" <car### [at] comcastnet> wrote:
> Smaller error bounds and larger counts don't necessarily reduce the black
> artifacts that show up when using radiosity.  In fact, in most of my
> experiments, the artifacts disappear with an error_bound of 1 or higher and a
> very small count.  That, of course, can lead to blotchy surfaces, missing
> shadows, etc., so most of my work now has been trying to figure out what
> else I can adjust...while also eliminating
> the artifacts.

Neglecting possible problems with the isosurfaces: I should have mentioned that
the artifacts being black means that rad is picking up that black color from
somewhere, and using it for some of the patches. Behind and above the airplane
model, there appears to be a big expanse of pure(?) black. A wall? A sky_sphere?
And the reflective table as well. Anyway, try changing one or both of those
colors to something wild like <0,1,1>. I'm willing to bet that the 'black'
splotches change color too. (Not that this will solve your overall rad problem--
but just as a test to possibly help zero-in on the cause.)

BTW: If you are using a newer version of POV-ray (maybe 3.8xxx?), there is now a
'no radiosity' switch that can be added to a particular object. It prevents that
object-- and its color-- from contributing to the overall mix of rad-patch

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