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Luoshuang's GPULightmass
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Originally posted by Muchasty View PostAfter some changes ( material One-Sided, replaced point light lines by spots ) Image look better, but still have some "sparks" mostly visible on the ceiling ( but is everywhere - mostly on walls )
Originally posted by Rawalanche View PostMost of modern path tracers use ray clamping (max sample intensity/max ray intensity) values to prevent fireflies. I am wondering of this GPULightmass uses it as well. If not, then that's what could be attributed to those blurred fireflies. It definitely should be used..
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Originally posted by lkkchung View PostThis looks really amazing. Any information on the CUDA version I need to have installed? I have 9.0176 and I got an error that said:
"CUDA driver insufficient for CUDA runtime version"
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The problem was two-sided material (replaced by one-sided ), not supported point light length ( replaced by spot), and sparks made from the one of LED emitter in my coffee machine model ( added node LightmassReplace to avoid bake cause all what is an emitter is used to add the light to the scene by the GPU Light mass).
Bake time 10 min. And I was very surprised when I saw that bake with active Swarm (I have prepared for net bake on CPUs) is made on all machines that have GPU on board in the network.
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Originally posted by Muchasty View PostThe problem was two-sided material (replaced by one-sided ), not supported point light length ( replaced by spot), and sparks made from the one of LED emitter in my coffee machine model ( added node LightmassReplace to avoid bake cause all what is an emitter is used to add the light to the scene by the GPU Light mass).
Bake time 10 min. And I was very surprised when I saw that bake with active Swarm (I have prepared for net bake on CPUs) is made on all machines that have GPU on board in the network.
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Originally posted by Luoshuang View Post
I believe this is more or less a bug in GPULightmass's adaptive sampler. Would you like to send me your scene (or a simplified version) for debugging?
Ray clamping is most useful when handling glossy/specular and other 'spiky' BRDFs. For lightmap baking the scene is pure Lambertian diffuse so it is currently not used. Still, I would try it to see its effectiveness.
Another very common case which can cause noise without ray clamping even in diffuse scenes are small and strong light sources very close to the surfaces.
On top of that, while I don't know how your GPU path tracing works, generally, GPU path tracers do not do ray branching, and they also generally don't support some irradiance/light caching for secondary bounces. In that case, having ray intensity clamping will actually help you that much more!
I have created two examples of the cases I've described above using offline renderer (Corona). All the offline renderers these days have ray clamping by default, set to some reasonable value (usually around 20, but for purpose of game engine, I think even 2 will be fine).
Here's example of the sunlight case with ray clamping values:
Ray clamping OFF:
Ray clamping 20:
Ray clamping 5:
Ray clamping 2:
And here is example of the other case, small strong light source near the surface:
Ray clamping off:
Ray clamping 20:
Ray clamping 5:
Ray clamping 2:
So I definitely think it would help you a lot
EDIT: You may want to right click and open the images in a new tab to see it better without excessive compression
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