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Illumination Pass Problem


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#1 RockKenny

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Posted 05 May 2012 - 12:57 PM

Attached File  edges.jpg   33.27KB   68 downloads
I think this ugly edges come from Illumination pass, how can i fix it in fusion? Cause can't possible fix it in 3d software.


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#2 Tilt

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Posted 06 May 2012 - 12:25 AM

The problem is the subsampling: the edges in the matcolor pass are anti-aliased but the illumination pass in the problematic areas is also anti-aliased - and against a brighter color instead of black which makes these artifacts stand out even more.

Basically, this is the issue that you would solve by unpremultiplying by the alpha before comping. You could do this with the sky (if that area were transparent) but the sphere can't be fixed that way.

Maybe a coverage pass can help you or a matcolor pass without subsampling. But I would go for passes that are already multiplied in your renderer: gi = raw_gi * matcolor, lighting = raw_light * matcolor.

#3 RockKenny

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Posted 06 May 2012 - 11:31 AM

If I understand correctly, the gi = raw_gi * matcolor, lighting = raw_light * matcolor do in 3d sowtware.
I can't to do it couse use cinema 4d, output passes there are very inflexible((

tried matcolor without aa, mb i do something wrong?(
http://www.getzilla....399/00.zip.html

#4 RockKenny

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Posted 06 May 2012 - 12:00 PM

i think only one option to render separately bg/fg

#5 protean

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Posted 07 May 2012 - 05:06 AM

The problem is as Tilt says. The way we fix it when using separate passes instead of just beauty is to recreate a colour pass that works by subtracting the additive components (spec, reflection etc..) and then dividing by the combined illumination. This is of course dependent on how the shader is constructed. Also we make our shader never output total black so that we never have any divide by zero issues

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#6 Tilt

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Posted 07 May 2012 - 05:31 AM

which connects this thread to the vray thread next door :-)
There's probably a reason why they derive their passes from a beauty pass. Never had issues like that with vray, but that's not saying that it doesn't have other issues :-)

#7 protean

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Posted 07 May 2012 - 05:56 AM

which connects this thread to the vray thread next door :-)
There's probably a reason why they derive their passes from a beauty pass. Never had issues like that with vray, but that's not saying that it doesn't have other issues :-)


We use Mantra so I don' think there's a way to do this in-render with it's arbitrary AOVs although it would help but no big deal really.




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