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Hey guys i sort of new to compositing in after effects, and this image is showing 2 separate render the green and the blue are rendered separate each matting each other out, now when i comp them together i am getting a halo around each where they meet up. It seems to be a premult issue but currently they are both 32 bit exr with a gamma 1.0 and they are brought in as straight matte in AE. I cant seem to get ride of this and its worse if i use PNG. Any ideas?
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Yeah it's the aliasing issue, it's always been like that. You can't matte one from the other and reverse, it's a mathematical problem of the AA.
the only solution is to render your green piece with the blue matted and the blue one with the green not visible to cam.
You will have a bit of pixels calculated that you don't need because it's hidden, but it's the proper way to do it. Same type of philosophy for post motion blur, where you need to render separated and not visible to cam the foreground.
The other way is rendering x times bigger without AA, so you've got everything sampled at 1. By having no AA, you will not have any maths aliasing problem, and then downscale the whole image. This is in theory, usually no one would ever do this because the not visible to cam trick is more efficient.
The other trick is to dupe your layers so that the aliasing is double each time, it's a quick and dirty way to do it, but it already saved my few times.
You've got the same issue with multimatte etc, everything that touch AA's got that issue.
Correct me if I'm wrong guys,
Stan3LP Team -
Can you try to re-interpret the footage as "premultiplied", choosing black as the color.
File>interpret footage>main.
You can also try to use a color for the background when render, that is similar to the background you're compositing it to in AE.Comment
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well in my case it CG going over CG and vicversa so i cant put a color in the environment slot that matches, unless i put the same render sequence in the environment slot???Comment
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Hello kriscabrera15
Yes - that would be the a working solution.
You could also try to render everything on pure black background, the AA issue will be still there but in most cases the result is acceptable.
For fine tweaks of the AA areas you could extract Coverage Render Element and use it as a mask.Comment
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