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View Full Version : General Compositing Stragedy.


Dreamdealer2099
03-09-2009, 07:32 PM
Hello everyone.I would like to know what's the most "common" compositing stragedy.I mean,it's clear that each project is unqiue but there must be at least one general way to compose the scene.Here is the one that i have been using so far:

Direct Lighting Pass*Color Pass=A
Indirect Lighting Pass*Color Pass=B
Resulting compose=((A+B)*Shadow Pass)+Specular Highlights+Reflection's color pass.

Also: Color Pass=Color Pass*Diffuse Occlusion
Reflection's color Pass=Reflection's Color Pass*Reflective Occlusion.

That's it.So what other techniques can be used?Thanks!

Seraph135
03-12-2009, 02:30 AM
Direct Lighting Pass*Color Pass=A
Indirect Lighting Pass*Color Pass=B
Resulting compose=((A+B)*Shadow Pass)+Specular Highlights+Reflection's color pass.

Also: Color Pass=Color Pass*Diffuse Occlusion
Reflection's color Pass=Reflection's Color Pass*Reflective Occlusion.


The way I read this it looks like your using your diffuse occlusion pass twice since its effect would show up in both the Direct lighting pass and the indirect lighting pass. If your diffuse occlusion pass is actually the diffuse amount for your textures then that is fine, but if you actually meant ambient occlusion then you wouldn't be compositing this right.

I'm not liking the looks of your Resulting Comp. I have an issue with the section

((A+B) *Shadow Pass)

From the looks of this it seems like you only have one shadow pass that includes both ambient and direct lights shadows. This will not composite back together properly this way. I render two shadow passes. One that are shadows from direct lights and the other is a soft ambient shadow pass (or an ambient occlusion pass). Then I'd do this with them.

Direct lighting pass (rendered without shadows and textures) * Direct shadow pass * color pass = A

Do the same thing with the ambient light passes. Then plus everything together after that.

Watch out for screwed up matte edges from pre-multiplied alphas. Its very common if your mulitplying passes together. Un-premultiply first if necessary.

Tim J

Dreamdealer2099
03-12-2009, 05:51 AM
Thanks for reply,will try it.

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