Exr + After Effects Alpha problem

[sumario]

Hi I am getting a wierd white halo on my windows after aplying magic bullets looks, I render a 32bit exr with pre-multiplied alpha on, if I set the footage on AE to alpha straight everything works fine, execpt when put on looks, when I set the alpha to premultiply is worse, anybody has any tips on this? is AE cs4 btw....

[flino2004]

did you render them out with black background?

[sumario]

Hi yes black background, premultiplied alpha........

[horoXhoro]

sigh~ i have this problem too...how to get a clean alpha without a black or white border @.@ please anyone...even i use straight and pre multiply alpha either is white or black border will shown on the border of my footage,....>< heeeelp

thanks

[ChrisL]

I have had this problem for ages now and have never fixed it from max/vray, and I have searched the net hi and low for an answer. This is how i work around in after effects you can use the Matte Choker from the Effects Panel/Matte/Matte Choker and adjust the choke 1 level as needed to remove the line, but if you want to change the colour of the object to far from the original color you will run into another problem but this may help you.

[davision]

I have had this problem too. I don't know if this helps or not, but it seems like it has for me (in some cases).... increase the antialiasing settings in Vray. I think if Vray has a chance to create better 'edges' you will minimize the 'fringe'.

[ChrisL]

Possible fix???
This morning I made it my mission to fix this as its been really getting on my nerves and i could really do with this working so I have spent all day trying every setting in vray with no real result, the closest I got from removing the band was as everyone has said save as TGA or alike with Pre-Multiplied Alpha, I also checked the Sub-pixel mapping in the V-Ray Colour Mapping section and setting the AA to fixed and setting it to around 8 but the render times are not worth it, nothing else seemed to have any real effect, the band is still there just not as bad.
So back to the net it was and I came across this very handy tutorial (http://vray.info/tutorials/mattes_compositing/) and noticed this guy was having no problem with the alphas the only thing he was doing different to me was he was using Fusion as opposed to After Effects to comp the render. So I took my nasty bandy .exr file on a 100+ mile round trip to a friends and loaded it up in fusion and the alphas where fine. Annoyingly though I only took the one file with me I should have taken a few but didnt think to do that at the time but the file was 100 frames and all frames looked very good. I changed the colors from red to green ect and did a few tests and all was well.
So I am hoping that somone that has Fusion and after effects could kindly do some comparisons also maybe a different image editing software anything that is not Adobe as I have found this post on the adobe forum (http://forums.adobe.com/message/2916381) having the same problem and he is not using 3DS Max atall. So my thoughts are that its somthing adobe is doing and not max/vray. Is there anyone who can take a PNG from max/Vray to PS/AE without this banding issue?

[jow]

Chris, regarding PNG In AE, if you set the alpha in interpret footage/main options, to Preltiplied - Matted with colour, and set the colour to black you shouldn't have the banding (asuming your matte is black). in PS it would be Matting/Remove Black Matte.

[egz]

In order to get correct comping with 32 bit files in AE you need to make sure that you save the file with a 1.0 gamma. Then you need to set up the AE project correctly. Make sure you work in a 32 bit comp, and that you have assigned a working space for viewing (sRGB/REC709 etc). You also need to check the linearize the workspace checkbox in the project setup.

[egz]

BTW: once I get back from Siggraph (actually on the way there now enjoying in-flight WiFi for the first time) I'm recording a LWF video tutorial for vray.info that's going to explain how the whole AE comping thing should be set up, among other things.