POV-Ray : Newsgroups : povray.general : radiosity brightness-- subtle problem at low values : Re: radiosity brightness-- subtle problem at low values Server Time
27 Apr 2024 00:05:39 EDT (-0400)
  Re: radiosity brightness-- subtle problem at low values  
From: Kenneth
Date: 13 Mar 2018 15:15:00
Message: <web.5aa822871cab2f0ba47873e10@news.povray.org>
clipka <ano### [at] anonymousorg> wrote:
>
> Having had a closer look at the whole shebang, there aren't any local
> effects to this: There is just a bug that will kick in whenever
>
>     (brightness/2)^(DEPTH+1) <= adc_bailout
>
> where DEPTH ranges from 0 to (recursion_limit-1).
>
> (Note that radiosity adc_bailout defaults to 0.01, not 1/128 as you
> previously claimed.)
>

Yep, just saw that in the docs.
Sorry for the confusion;  I was recalling the 1/128 value from *something* in
v3.6.x days-- obviously not adc_bailout though. (Actually, I had forgotten that
radiosity has its own adc_bailout; I was earlier referring to the
global_settings value. Which isn't 1/128 either, but 1/255!)

So, from the equation... using the .020 'threshold' and DEPTH of 0,

(.020/2)^(1) <= .01   or, .01 <= .01

.... which is where the problem occurs.

I guess the safest bet right now is: Don't set rad 'brightness ' below .021!
Which nobody would normally do anyway ;-)

Thanks for taking the time to do such a deep analysis.


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