POV-Ray : Newsgroups : povray.binaries.images : Impending Disaster : Re: Impending Disaster Server Time
6 Jul 2022 00:22:38 EDT (-0400)
  Re: Impending Disaster  
From: Kenneth
Date: 1 Feb 2022 16:35:00
Message: <web.61f9a759941abfdd4cef624e6e066e29@news.povray.org>
"Kenneth" <kdw### [at] gmailcom> wrote:
> "Bald Eagle" <cre### [at] netscapenet> wrote:
> > "Kenneth" <kdw### [at] gmailcom> wrote:
> >
> > > 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...
> >
> > Hmmm. Yes, if this is indeed the case, then we may be running into that
> > color-vector multiplier thing.  Anything * <0, 0, 0> = <0, 0, 0>.
>
> That's a good and interesting point. In effect: If *large* rad patches are a
> blend of colors from various points/objects in the scene-- which I *think* is
> the case-- and if one of those patches is pure black, then maybe the entire
> 'blend' is reduced to black there(?). I have never tested that, but it's worth
> an experiment to see what happens.

Let me re-phrase that, so that my own idea is more clear:
If a SINGLE and large rad patch is a blend of colors from various points/objects
in the scene-- which I *think* is the case, depending on other rad settings--
and if one of those COLORS happens to be pure black, then maybe the entire
'blend' for that patch is reduced to black(?).

Of course, in a typical radiosity scene with a reasonable 'count' value, there
are lots of overlapping patches on objects-- so it might be difficult to
tease-out this blackening effect, if it's indeed happening.


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