Le_Forgeron <jgr### [at] freefr> wrote:
> Le 28/07/2017 à 11:44, gregors a écrit :
> > Hello
> >
> > Every time when I tried to render the scene I've got different results. The
> > difference was in the lighting of the scene. In the scene there is only one HDR
> > sky_sphere.
> >
> > I am using official 3.7 build on Windows and unofficial MacOS build 3.7.1.
>
> It can be reproduced simply adding +KFI0 +KFF10 (here on linux, so not
> platform specific)
>
> Yet, have you read http://wiki.povray.org/content/HowTo:Use_radiosity ?
>
> Radiosity is not reproducible (there is a lot of randomness in it), you
> need to save & reload radiosity data if you want always the same result
> (such as in animation).

Since you said that I had to check to be sure, I know there's always some
resampling going on even when always_sample off is being used. Or so I believe,
and the doc seems to say same.
Having tried the animation using command line +rf"hdr_rad" for one frame and
adding +rfi for the other frames, animated it still flickers from changes to the
radiosity.

Before doing that I was trying higher count and some other settings. I had also
used a different hdr file in place of the kitchen.

I was able to render successive frames without visible deviations by using count
>1600 called the Halston method in the docs.

Maybe the other settings contribute to the smoothness too.

I'm still not very good with radiosity settings, I tend to find what looks best
for particular scenes while trying for fast renders too.

Here's that global_settings from the test scene.

global_settings {
 assumed_gamma 1

  radiosity {
    pretrace_start 0.08
    pretrace_end   0.02
    count 1601 // >1600 is Halston method

 always_sample off
 //max_sample 0.9

    nearest_count 12
    error_bound 1.2
    recursion_limit 2//3

    low_error_factor 0.4
    gray_threshold 0.0
    minimum_reuse 0.015
    brightness 1

    adc_bailout 0.01/2
  }
}

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