CGTalk - passes rendering and after effects

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svenip

08-19-2002, 08:29 AM

i've posted this in the AE forum too, but it seems as a problem from maya.

for my current project i wanna use AE (just to get familiar with it). usually i render it all in layers and passes (diffuse, specular and shadow). my problem now is that even AE or Combustion doesn't recognize the alpha of the specular pass. there is one in the image (fcheck shows, and shake recognizes it) but AE and Combustion show me a big white screen for my alpha :)

the other passes are ok, alpha is good.

:hmm: :hmm: :hmm:

thnx in advance

i will go back to shake after this :)

wedge

08-19-2002, 08:45 AM

what is your specular rendered out as? i usually use TGA files, and AE has never given me any problems with the alpha.

svenip

08-19-2002, 10:27 AM

i tried every image format possible :hmm:

AE won't recognize the alpha of the file. but just in the specular channel.

SirRender

08-20-2002, 07:04 AM

I do a lot of multipass render compositng in AE and the same has happen to me rendering from different packages, specially on a specular pass. Even when the alpha comes through, it starts to get a little thick in AE after a lot of layers and precomposing. What I do now is not even bother with an alpha for a specular pass anymore, but instead I make sure everything else is black. Then in AE, I'll either "add" or "screen" the layer on top of everything else and adjust opacity to taste.

I understand that doesn't answer you question of where the spec alpha went in AE, but I assuming you already checked the "Interpret Footage" settings for the spec file/layer and made sure that it's set to "Straight-Unmatted."

Hope that helps...

svenip

08-20-2002, 11:11 AM

thnx for the reply :)

ahh, i have to write a note to Adobe :thumbsup:

swag

08-20-2002, 01:43 PM

maya images are premultiplied alpha not straight which is the default for AE make sure AE is interpreting the files as premultiplied with black

svenip

08-21-2002, 06:43 AM

the thing is that for the specular AE don't ask me how to interpret the alpha, it's just not there for AE :)

Shannon

05-14-2003, 07:20 PM

Maya alphas are premult by default with an option to change that. Look it up in the docs.

And you'll need to Right click on the footage in the project window (not the composition) and choose interp footage.

I suggest you turn off premult in Maya and batch render all passes.

Good luck

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