Render Layers Maya Help

K17020

Hey everyone, I'm currently working on a production with a few people and I have a question that I cant seem to find the answer for. It involves render pass, what I'm trying to do is one have one object project its shadow on to another object ,but not have the object display in the render. That way I can go and composite it later.

Ive been using this tutorial to help me ,but I've come up with anything. If anyone has any idea I would appreciate it very much if you can help

http://www.3drender.com/light/shadpass.htm

Thanks

r_fletch_r

If you want to make an object cast shadows but not render in maya turn off its primary visibilty. I usually do it from the render tab of the attribute spreadsheet.

K17020

Ive already tried that and I don't get the results that I want. The shadow doesn't end up on its own layer

Warheart

I think what you probably want is the "use background" shader. This can be set up on a render layer to give you a pass with only shadows. I haven't set this up in a while so I don't remember the exact settings you need to use with it but you can take the output of the use background (think you may have to invert it with a reverse node) and then stick the output of that into the outColor of a surface shader and then assign it to everything on that render layer. If I remember rightly though it only works with depth map shadows and not raytraced (could be wrong but that's what I remember).

If you're still stuck I'll work out the steps to set it up if I've got time tomorrow or something.

r_fletch_r

you can also use mia_matteshadow. if your using mayas software renderer you will need to use 'use background' (dont know if they made an alternative) but if your using mental ray then use mip_matteshadow. its as awesome shader. It does bounced light, Ambient Occlusion and directional shadows.

you can see some examples of the shader here.
http://mentalraytips.blogspot.com/2007/10/production-shader-examples.html

K17020

Thanks for the help everyone ,but I figured it out ,but its a really janky way of doing it, but it gets me the results that I want