View Full Version : Baking occlusion to a file in Maya - MentalRay

03 March 2011, 03:13 PM
First off I'm using maya and mental ray.

I'm dealing with a fairly large static scene for an animation and I need an occlusion pass. It seems inefficient to render occlusion on every frame since it's not actually changing. I know I can bake to texture which would require me to take all the objects in the scene and layout a new UV set. But does someone know of another technique, maybe similar to a point cloud where the information can be reused with camera movement. Thanks!

03 March 2011, 10:08 PM

Hmm, couple ideas:

- Does mental ray support ptex yet?
- I guy here has written a 3rd party plugin for writting/reading ptcs in MR, but im not a big fan of relying on plugins
- You could write out a final gather point cloud, set it to reuse, and then use the FG occlusion node, although i find it buggy
- I know there are occlusion cache options in the render globals, but who knows what they actually do.

Probably not that helpful!


03 March 2011, 10:45 AM
I haven't tried but how about these point cloud shaders for mental ray?

03 March 2011, 03:10 PM
Thanks for the prompt responses!

As far as I know, Ptex isn't officially supported in Mental Ray yet. Though I've found some "hacks" for it, and they still need UV's to be created, which seems to defeat the point.

I'll check out the ptc plugin. I don't really care for relying on plugins as well.

I've tried the occlusion cache in the render globals, not sure if I was using them incorrectly but the results weren't the quality I need and render times weren't that much better with higher quality.

Thanks for the suggestions! I'll explore deeper into these options.


Dan Wade
03 March 2011, 03:43 AM
yea, PTC's would be lovely. Im so use to getting my occlusion and even shadow data in ptcs through renderman, seems silly having to render them per frame in MR.

03 March 2011, 09:50 PM
I'm glad I'm not the only one who feels this way.

I tried out the point cloud plugin for MR and it works fairly well but not for a large scene. Especially since it's vertex based and using subdivisions at creation time takes way too long to create the point cloud. Looks like I'll have to stick to the raytraced method for he time being until something more efficient comes to my attention.

What I may do, is use 3Delight to create the point cloud and then either use 3Delight to render that pass or use the PTC mental ray plugin to render out the pass.


03 March 2011, 10:24 PM
PTEX will be the next best thing if it's ever implemented.

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03 March 2011, 10:24 PM
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