CGTalk - Oppacity map with an occlusion pass

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BenDstraw

06-09-2006, 09:16 AM

I have a skylight scene with some trees using oppacity map.(not sure of any other way of making them.) but i want to make an occlusion pass to go with it but when i use the ambient/reflective occlusion shader to all of my objects.(in max 7) the trees are grey squares which i forsaw coming but do any of you know how to keep the objects in the shape of trees while still using ambient occlusion.

walee

06-10-2006, 12:43 PM

do a render pass with the trees to get the alpha of the trees, then use the alpha mask of these render pass to mask the AO pass and composite your image in the program of your choice.

Rice

06-14-2006, 10:39 AM

I run into this a lot with characters that have transparent objects. What I do is create an alternate ambient occlusion material for the character that has the transparent masks from the character included in the multisub object shader. If objects don't have transparency just instance a base ambient occlusion shader in the other multisub object slots. For characters you can sometimes end up many different alternate materials for them that you swap in and out during your render passes.

Alternate Material Examples: Master Shader, Ambient Occlusion Shader, Wet Shader, Damaged Shader, etc.

Hope this helps.

Cheers,

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