POV-Ray : Newsgroups : povray.binaries.animations : radiosity in animation-- a partial solution to 'flicker' : Re: radiosity in animation-- a partial solution to 'flicker' Server Time
25 May 2024 22:40:21 EDT (-0400)
  Re: radiosity in animation-- a partial solution to 'flicker'  
From: William F Pokorny
Date: 28 Nov 2020 10:40:31
Message: <5fc26f6f@news.povray.org>
On 11/24/20 2:10 PM, Kenneth wrote:
> Radiosity in animation suffers from a kind of jitter or flicker problem, even
> with high-quality settings... a result of the random nature of the rad 'light
> patches' from frame to frame. Using a SAVED radiosity file, from an initial
> camera viewpoint, would seem to solve that issue, but it's only partially
> successful: As the camera moves-- and the scene's objects move as well-- the
> saved radiosity file is no longer adequate to produce an expected smooth effect.
> I came up with an interesting solution to part of this problem, at least for
> POV-ray v3.8xx and maybe 3.7 too, which is more easily explained in an animation
> test.
Cool idea and demo! Not positive, but I think if you both loaded and 
saved the radiosity samples the "new" ones would get appended to the 
file by POV-Ray (no need to edit). If so, it should be you could run a 
sampling of the total frames where you let POV-Ray keep adding to the 
radiosity file. This would be an initial pass for the purposes of 
creating the "all-frames" sample file used then for the all frames 
renders. Your file size concerns, still a worry, but...

I've not been following the radiosity discussions closely, but there is 
since v3.7 a +HR or High_Reproducibility option. Have you tried this? As 
far as I know, it still works only with radiosity though its initial aim 
was broader.

IIRC, what it does is change the seed to the render block "number" so 
even with multiple threads (SMP) you get the same random numbers (and so 
radiosity ray samples - at least by ordering) in any given block. The 
render image size and render block size would need to stay constant too 
of course.

Another option which obviously helps with reproducibility is running 
with one thread.

Bill P.

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