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
26 Sep 2022 02:18:03 EDT (-0400)
  Re: radiosity in animation-- a partial solution to 'flicker'  
From: William F Pokorny
Date: 5 Dec 2020 07:41:52
Message: <5fcb8010$1@news.povray.org>
On 12/4/20 12:49 PM, Kenneth wrote:
> William F Pokorny <ano### [at] anonymousorg> wrote:
...
>> ---
>> C seems to stand for color. (There are other unused classifications)
>> The number after the D is depth. I've only ever seen 1 or 2 - maybe if
>> recursion depth increased?
> 
> Yes, you're right, it's recursion_limit. (In my tests so far, I had set it to
> 2.) I ran another test with somewhat high-quailty settings (to produce a LARGE
> saved rad file), and cranked resursion_limit up to 20. Now I see data lines
> starting with C3,C4 etc. Interestingly, they 'top out' at about C8-- with fewer
> entries too-- which agrees with the documentation about higher recursion_limit
> settings having less and less of a visual effect on the render.

Thanks. Good to know.

>>
>> The next three float values are the location...
>> ...
...
> 
>  From my animation tests with a moving camera, I assume that the x,y,z
> values/direction vectors have something to do with CAMERA's viewpoint as well
> (whatever it happens to be.) That is, if I understand your description
> correctly.

I think only to the extent the camera rays set where the code will look 
to take samples. Nearly positive, the stored sample coordinates are 
locations in global scene space. Most, excepting media ones, on 
surfaces. Normals, distance and direction information would all be 
relative to the surface(1).

(1) - Wonder what happens with normals in media...

> 
> IMO, there does seem to be a similarity:
> 
(Interesting experiment - ie reflection 8)

On similarity between photons and radiosity, I was speaking mostly about 
saved file formats.

Photons and radiosity start in fundamentally different ways. Photons 
shoot rays (forward) from light sources into the scene to create photon 
samples. Radiosity traces backward in the more traditional ray tracing 
way and it might find light sources or not depending on the ray tracing 
bend/bounce depth.

Both types of samples are gathered and merged in with the usual ray 
tracing results for each ray to give a final result.

(One more thought. If there is no way to stop after the radiosity file 
is updated, we should be sure options like AA are off to save that time 
- if you are not already doing this.)

Bill P.


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