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KarimNassar
08-09-2011, 10:38 AM
Hello
I have an issue with color id passes I render in maya.

Whenever I try to recuperate the color selection, whether it is using the select color range or the magic wand, I am unable to get a clean selection and always end up with a fringe or too hard of an edge.

When I render an alpha pass all I do is control click on the layer or use it directly as a mask which gets me a perfect selection. But when using a color id pass with multiple colors I cannot recuperate the different parts without a bad edge.

see issue here:
http://img16.imageshack.us/img16/8324/fringeg.jpg

I tried playing with the edge contrast option in the maya render tab and with selection tools in ps but with no luck.

How do you achieve a proper id pass in maya and a proper selection in ps?
thanks!!

lauras
08-10-2011, 06:08 PM
Hello,

Are you rendering a Coverage pass with your Label pass? The Label pass is aliased (not anti-aliased) so you need the Coverage pass which provides your edge. Check out this blog post on these two passes, it might help. This particular post uses these 2 passes in Nuke but you may find a way to translate the methods into PS.

http://www.sigillarium.com/blog/lang/en/379/

Hope this helps!

L

KarimNassar
08-11-2011, 12:53 PM
Actually I was just rendering a beauty pass with different surface shaders assigned to the objects so I guess that was the issue.
Thanks for the link I did not know you could separately stores anti-aliasing data in a render.
I tried the tutorial and got the separate file to render but with no information on it.
Not a straight forward workflow to me so I have a hard time doing it but I will redo it until I get it right.
thanks for the help!

InfernalDarkness
08-16-2011, 05:40 AM
While I understand the benefits of using color-based object passes, I've always found it best to just output a matte-pass based on either the object's shape node or the material shader for a set of objects. You get a much higher-quality grayscale, no bit-depth limits (32bit is plenty), and you don't have to struggle with screen-space RGB stuff. They work just like the alpha channels you're used to, really.

Just an idea.

KarimNassar
08-16-2011, 12:08 PM
Sounds great InfernalDarkness (http://forums.cgsociety.org/member.php?u=326526), so let's say your camera view is completely occluded with objects, you still get an alpha pass per object based on their respective shape node?
How do you do that?
thanks!

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