View Full Version : how to key object-id-pass

06 June 2008, 03:19 PM
How can I properly key an object-id-pass in combustion? I know how to do it when it is all together in an rpf, but how can I do it when it is in a separate image? When ever I try to key it, I get the antialiased edge remaining.

07 July 2008, 12:01 PM
How are you saving the image? Renderer, Format and settings? Maybe try a negative matte control to grow the key. In scanline, it appears it always filters..

07 July 2008, 12:50 PM
Well, the images come out of 3ds-max, so I'm quite free regarding the format. Normally I use 100%-jpegs if I do not have to save any alpha.
Do I really have to pull a real key with the Discreet-Keyer and finetune all those settings? Is there no possibility to do it with something like stencil luma or anything?

07 July 2008, 06:20 PM
The random color render node ID is really worthless outside of RPF. If you're using vray, I'd use the MultiMatte render element, which gives you only three mattes per image, RGB, but because they're unique they're alaising comes out perfectly.

If you're not using vray, you can set the renderNodeID to render the wire color, and set the objects wire color to pure Red, or Green, or Blue. You can then use the \Channel\Set Matte operator with the selected color channel RG or B.

Made a quick test scene to show the setup if your not in Vray.. I like PNG's as they're lossless... Jpgs are evil..

07 July 2008, 07:03 AM
Thanks man, I will give that a try!

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