MR attributes in materials attributes

[Jozvex]

The Irradiance attribute controls how much Final Gathering and Global Illumination effect that material. With the attribute set to white, FG and GI fully effect that surface. Lessening the colour lessens the effect of GI and FG.

You can even tint the colour of FG and GI by changing the Irradiance to say, blue or red.

The Irradiance Colour attribute has something to do with Mental Ray lightmaps, but I'm not too sure about that stuff yet.

:thumbsup:

[Tornado7]

Thanks Jozvex
:bowdown:

[brunner]

Actually i think it's the other way around:
The 'irradiance color' controls how much FG/GI the object receives, and the 'irradiance' controls how much GI/FG "transmits"

I'm not sure about this though:hmm:

[Tornado7]

Thanks anyway;)

[Jozvex]

Originally posted by brunner
Actually i think it's the other way around:

You're right! It is the other way around! :scream:

I didn't have Maya open at the time to check that I was right. I should have read my FG tutorial hehe.

Thanks for the correction brunner!

:thumbsup:

[huijiao2001]

It controls how much photon energy is absorbed and/or reflected back into the scene when a material is struck by a photon. If your material is pure orange and you set your irradiance parameter to blue, then any object that receives the bounced photons will inherit some amount of blue, not orange.

In another example, if the material is pure white, chances are that it will reflect a lot of energy back into the scene and wash it out. Therefore, it's often necessary to reduce the irradiance parameter so the reflected energy is still white, but not so intense. This is required to mimick materials such as fluffy cotton vs. polished plastic which reflect energy differently.

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