CGTalk - Mental Ray - object visible, not casting GI shadows?

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sugarandfat

04-26-2006, 04:19 AM

I have a sky sphere in my scene, which I want primary visible, as well as in reflections. I'm lighting the scene purely by IBL.

Having the sky on, even if I disable every kind of Maya and MR visibility, still blocks the image lighting.

I'm sure this has been raised before but can't find anything.

thanks

Daniel.

jeremybirn

04-26-2006, 05:55 AM

If it isn't visible in reflections then I think that should take it out of your FG computation, too, doesn't it?

-jeremy

sugarandfat

04-26-2006, 06:14 AM

Yep, but that's the problem. I want the skysphere visible in reflections but not cast GI shadows.

Daniel.

Chris-TC

04-26-2006, 11:03 AM

Well, turn off Receive Shadows and Cast Shadows. Also might wanna turn off FG Caster.

sugarandfat

04-27-2006, 12:17 AM

Ok, sorted it. What you have to do is this:

Ignore everything under 'render stats' and 'mental ray' in the shape node, go to the node above (don't know the technical name), unrol 'flags' under 'mental ray'.

Turn of 'derive from Maya', make visible-use inherited, trace-no, shadow-no, caustic-hidden, globillum-hidden.

The problem is, the surface now won't recieve any light from IBL. But you can still map into the incandescence channel, which is perfect for a sky sphere. No idea what you'd do if you still wanted the object lit by final gather.

Daniel.

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