Hasta La Motion!

I would love to be able to change colors from my maya renders in post using label/object id passes with everything embedded in an exr.

But I have run into problems…

1.I understand that this is a maya question but I can’t find any simple ways of getting my label/object id/coverage passes out from mayas framebuffer. Do I have to assign an mi_label to every object in my scene manually like Chapter III on http://www.sigillarium.com/blog/lang/en/379/#III ?
At http://usa.autodesk.com/adsk/servlet…P=OTC-RSSSUP01
They mention that you could use the Diffuse Material Color pass for masking if you’re just using straight colors, is anyone using this approach?

2.If I do get those passes out (hopefully with some help from some of you) I understand that the label pass will be without aa, now I have been searching quite a lot and found a thread where Hugo had written a macro to get hold of the id’s and then apply some fake aa but it seems that the gizmo is broken in newer versions of nuke.
Therefore I’m requesting a straight out nodal workflow (no gizmos) that helps me getting those id’s as an alpha channel.
I can easily do this with a shuffle node when it comes to r g or b, but how can I get hold of custom colors to use as a matte?

3.What are coverage passes for? I figured they were used to make aa work correctly with non-aa passes hence skipping the need for Hugos fake aa controls in the gizmo. If not… what can one use them for in post?

4.Is anyone using this workflow successfully or will there always be problems when changing an objects color afterwards? My ideal situation would be to be able to do color variants of products I’m rendering without having to re-render everything for each color version.

Thank you very much in advance, hope some of you can shed some light on this.