View Full Version : On-demand geometry in MR?

02 February 2005, 04:42 PM

I'm diving in at the deep end here (never did any MR shader writing before, and only have vague notions of what's involved, but I'm busy reading up on it):

I'm going to start working on a bird character and will need realistic feathers. I was hoping that using the MR "hair" geometry shader type I would be able to create instanced feathers at render time. I know it's possible to use bounding boxes and callback functions in the MR hair shader so that it only creates the feather geometry if it's visible to the camera. So I think I can sort out a feather shader given a little time.
What I don't know is how to link this geometry shader to my Maya scene and the scripts that will populate my bird with instances of the feather? How do I actually get the geometry shader to create output in my scene, and how can I control the placement of the feathers?

Can someone help me out with a high-level overview of what's involved, starting in Maya and going into the MR shader? I'll sort out the details myself, I just need a few pointers...



02 February 2005, 07:54 AM
create a dummy object (eg polyCube) then select the transform node of it (not the shape) and under mentalray section click the Geometry Shader MapButton and choose your geometry shader.

hope it helps

02 February 2005, 08:38 AM

thanks for that. at least now I know where to look. It's strange how you can overlook things...

so, to elaborate a little: i'll create a geometry shader for my feather (an Object of the type Hair, right?) and then I'll hook in into this slot on the transform node of the dummy object. I'll try that...

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02 February 2006, 09:00 AM
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