Kenneth nous apporta ses lumieres en ce 09/08/2006 03:57:
> Jaime Vives Piqueres <jai### [at] ignoranciaorg> wrote:
>> Hi Ken:
>>
>>    It's seems not that bad to me, but indeed it can be better. First, to
>> control the color spill, just use gray_threshold.
> 
> Sorry, I may have described things the wrong way.  In my scene, it *seems*
> that there should be MORE color spill onto the ceiling, from the
> saturated-color walls. But then again, the tall (distant) box shape seems
> to show quite good color spill from the red wall.  So perhaps I'm looking
> for an effect that really shouldn't be there. Difficult to tell!
> 
>> For more defined
>> shadows, error_bound should be lower and nearest count perhaps higher.
> 
> Yes, I'm beginning to understand that a lower error_bound value "breaks up"
> (and distorts) the ray-created color "patches" into smaller and smaller
> pieces, which would seem to be more accurate. (Smoothing out those many
> patches has proven difficult for me, though. As I understand things, a
> higher count is then needed.) A higher nearest_count DOES radically improve
> things--but from what I've seen, it appears to make shadows less defined,
> sort of smoothing them out. Am I mistaken about that? Is it interacting
> with "something else" that I should change?
> 
>> In the other hand, I don't think you need more than 2 bounces, 3 at
>> most (recursion_limit).
> 
> I'm still trying to understand this "bounce" idea. But you're right, higher
> recursion_limit values seem to have less and less of an effect. I've
> settled on 3. Is it correct to assume that the more bounces, the more the
> various radiosity-created colors in the scene blend together and become
> MORE muted? If so, it sounds like something to be avoided (?) As you can
> see, I'm really struggling with these concepts!
>>    Hope this helps...
> 
> Yes indeed! Thanks.
> 
> Ken W.
> 
> 
> 
A high recursion_limit can be good if you want light to spill into somewhat 
distant or convoluted areas that would otherwise remain unlit. You are correct 
in your observation about diminishing effect with higher recursion_limit. It's a 
normal effect. It diminish acording to the diffuse value of the surfaces and on 
the colour of those. If you bounce upon a pure red surface, then on a pure green 
or blue one, there is no light left as the first returns only red and the second 
returns only green or blue that they don't receive.

-- 
Alain
-------------------------------------------------
An idea is not responsible for the people who believe in it.

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