CGTalk - Shake iadd help!!

ahsiong

09-06-2008, 01:01 PM

Hi, I need some help on the IAdd node.
When i use tat in my compositing tree and apply a Over node at the end of it,
I got incorrect edges(tat look like thin outlines in image A) in the composition.
The correct image should look like image B as shown below.
http://i33.tinypic.com/35cg77k.jpg
Can someone tell me wat I am missing? Thanks!!!

Kai01W

09-06-2008, 11:06 PM

My guess is that your also adding up alpha values (depends on which of your passes have which alpha). So you'll get alpha values above 1 which is not nice.
Do a copy channel node and copy the original alpha back in right before you do the over.

-k

beaker

09-08-2008, 04:24 AM

try unpremultiplying the images first with a MDiv, then do the iMult and then repremultiply the images with a MMult.

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