Getting Mental Ray to obey lights Emit Spec/Diffuse Flags

[bgawboy]

I don't know how your mirror ball parameters are set up, but this might work ...

By default, without specifying a light list, Maya translates the scene so that custom mental ray material shaders will use all the lights. What about using the light list explicitly for the mia_material, and only putting the sun in that list?

That list is used for direct lighting, and what you want to control is the specularity from direct lighting. Now, if you are actually using any direct diffuse lighting for this ball, it could reduce that without you really wanting it to. Then, for that, you might be able to raise the diffuse color value a bit to compensate, but they wouldn't be from the correct directions. However, I don't see much, if any, direct diffuse reflection from this image.

Also for mia_material, did you learn that the IOR controls the amount of object reflection, what I like to refer to as indirect specular/glossy illumination?

[Jaidek]

Hey bgawboy,

Thanks for the information, I will give that a shot and see if it helps. Especially on the IOR. This chrome ball was a exagerated example of my problem. I will be lighting objects that have a variety of surface materials (plastic and metal). So the shaders would need to have diffuse lighting from the light dome in order to properly illuminate the non relfective surfaces.

I have exhausted my ideas on how to remedy this problem. So for now I am working with standard Maya shaders (yack) because they obey "emit spec" when rendered in MR. I have also emailed MasterZap to see if he might know of a work around. I really hope so, because mia_materials is an awesome shader.

Thanks again for the help,

[wizlon]

Same issue here, I hope there is a workaround/fix soon, for all mentalray shaders.

[ACamacho]

Autodesk would have to recompile the shaders to respect those flags. At least as from looking at the shader writing examples they give in the mental ray shader docs (hidden deep in the help file). So you can wait till they implement that or recompile the shaders yourself. Am I correct in this?

But there is Mega_TK if you don't want to use maya shaders. Pretty useful shader and has equivilant "light" shaders(for point,spot, and direct). They have "emit" checkboxes that work (provided you use the mega_tk for everything).

http://www.puppet.cgtalk.ru/download/megatk_e.shtml

[wizlon]

Posted the question on Alias Support, and they said, "We are aware of this limitation. I will investigate to see if there are any other workarounds"

Hope this is fixed soon.

[Ash-Man]

EDIT >> I'll take that back
I just relaized I had FG ON while I was tresting

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