View Full Version : use ambocc as a shadow pass?

12 December 2006, 08:32 PM
the occlusion preset in MR render layers gives the perfect shadows for a scene im doing. the only problem is i need them on a separate pass for live action compositing, so i cant have my shadow receiving object (which is a stand in for a real object) self-shadow... i cant figure out how to disable this in the shader.

if its not possible, whats a good way to get the same look as that shader for the shadows?

12 December 2006, 08:59 PM
Why not just render out a quick matte to mask out your stand in object. You can then remove the self-shadowing in comp?

Otherwise, check out ctrl-occlusion it may have an option to remove self-occlusion.

edit: sorry, re-read your question, the first idea wouldn't work....

12 December 2006, 09:40 PM
but it requires manuall rotoscoping that i'd like to avoid as i still have 15 shots to go :)

12 December 2006, 08:23 AM
I haven't played with it much, but I believe you can do this with ctrl.occlusion. Somehow you specify occlusion groups, that dont occlude themselves, only others. I may be wrong here, but you might want to look into this possibility.

edit: I read up on ctrl.occlusion. I dont think its quite right for your needs.

However after re-reading your posts I thought maybe you could just use the mib_ambient_occlusion, but not as a layer over-ride. Selectively assign it to your receiving objects, then assign a white surface shader to your casting objects. I think this would work.

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12 December 2006, 08:23 AM
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