Not sure if it would work for instances, but in MR, there's a "primitive id" item in the ray state. I think you'd need a custom node to access that. It's actually possible to get custom values into the native label pass, but if I'm not mistaken, you need to do it on an output shader (again, requiring a custom node).
Otherwise, as a simple alternative, I'd suggest writing a random id/color from ICE to a custom render layer. If you really need the aliased edges, you could render oversize with AA dialed off. In theory, you could also set the render layer to use the same "statistical 'mode' filtering" mechanism the object ids use, but I don't believe it's exposed in the GUI. If you cook out an mi2 it might be doable. If you look in the MR docs, I think it's a "+" flag or something on the output statement in the mi2 files. Forgive me if I've gotten any of this wrong. Memories of MR are getting fuzzier by the day. (Not that any of this is easy in Arnold either). On Wed, Nov 13, 2013 at 11:12 AM, Eric Lampi <[email protected]> wrote: > Anyone work out a way to render a unique color per particle/instance, or > somehow apply a unique object ID to the instances so that the MR object > label pass will work? > > > Thanks, > Eric > > Freelance 3D and VFX animator > > http://vimeopro.com/user7979713/3d-work
