nemesis nous apporta ses lumieres en ce 2008/01/24 22:24:
> jhu escreveu:
>> Thanks! My global settings are listed below. What do you suggest I 
>> change?
> 
> hmm, no photons for caustics?  It seems radiosity is creating some weird 
> kind of caustics by its own, except it's black!
> 
> Now, count 1000 and error_bound .05?!  whew!  Took a few days to render, 
> huh? ;)
> 
> In my radiosity scenes I like more fine-grained radiosity shading so I 
> generally go for pretrace_start 0.04 and pretrace_end 0.008 or something 
> like that.  But I go with error_bound .2:  it's acceptably slow and 
> gives good results for the blending of blotches, specially coupled with 
> nearest_count of about 16.  Count is about right, though I first try 
> with lower counts, like 200 to 600...
> 
> As for the dark spots, the correct way to get caustics in povray is with 
> photons.  Radiosity has problems with black spots and glass surfaces. 
> Use a first radiosity pass without the reflective or transparent 
> surfaces, save that rca file and then render the final image with 
> photons and the reflective/transparent surfaces back.  Test without 
> photon first, then good luck. :)
In this case, replacing the radiosity with photons don't look feasible. The 
caustics are a projection of the sky. You'd need to use a light dome, possibly 
composed of many area_light with photons{area_light}. You'll end up with tons of 
photons, meaning a photons phase that will be extremely long and a memory use 
that may get prohibitive.

-- 
Alain
-------------------------------------------------
You know you've been raytracing too long when you've tried to scan your face for 
a texture.
Quietly Watching

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