Passing objects render color on to strand/particles color...

[wacom]

I am wondering about how to pass the color of an object (it's render color) to a particle or strand setup without using the texture look up based method.

Right now I have it "working" by having the object in one pass, passing it's color to a render channel texture file(s), then in the next pass having the particles using the "Get Texture Map Color" compound with the previous passes render channel assigned to the Texture_maps texture.

I'm wondering if there is a less clunky, more dynamic way to do this all in one pass maybe using something in the render tree, ICE tree or both?!?

Thanks,
Gideon

[CiaranM]

Another method would be to use a CAV lookup. The mesh's vertex color could be looked up in the render tree and also looked up by particles (e.g. get emit location > cluster property > color). You might control the CAV map by painting or more procedurally in another ICE tree. But, of course you'll be limited to simple colors and vertex resolution.

[wacom]

So are you saying I could do a CAV look up that would pass it along during the render process or is that something I'd have to do before? Can you animated a CAV map even?

To be clear, I want to take the lighting from a surface (like say phong or toon) and have the strands color read from that in one pass. Maybe I misunderstood your solution though?

[CiaranM]

No the method I describe is just for surface colors, not shaders. It's just a little quicker than having to have a prepared texture map on the geometry, if all you want to do is match simple colors..
You can't lookup surface lighting information on a geometry, you'd have to bake that. You can of course write a very simple shader using ICE nodes, so that you can shade or even shadow the particles to approximately match the shader on the material.
Or, your surface and particles could share the same material.