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eikonoklastes
04-17-2012, 06:15 AM
Is it normal for glossy samples to affect the brightness of the reflection?

Below are attached 2 images of a simple scene - cube and plane with mia_material_x_passes and preset Copper applied.

Everything in the 2 renders is the same except the reflection glossy samples.

There is a marked difference in brightness and I'm not sure why. This happens in both 2012 and 2011 and with both Adaptive and Unified Sampling.
Bitter
04-17-2012, 07:45 AM
It does, what we find is that lower samples make it a little more dim. And in some cases it's in your specular channel. We just tune to look and quality anyway so it's not been an issue, just an interesting side-effect.
eikonoklastes
04-17-2012, 11:08 AM
Hmm... I'm getting the opposite. Lower samples is brighter for me. Also, is it a bug with mental ray? I got a colleague to do a test on mr for max and it was happening there too. When he used Vray there was no such discrepancy across glossy samples.
Bitter
04-17-2012, 01:54 PM
Vray uses a different method to compute glossy than mental ray so I can't really be sure what that affects. I know the microfacet model in the mia_material generates correctly stretched reflections because of this model (preturbing the normal).

It's different, but not something that has caused us any trouble.
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04-17-2012, 01:54 PM
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