Re: alpha matte? by Steve Sayer on Sep 27, 2011 at 7:26:23 pm
You mean you want the box to hide the sphere, but you still want the shape of the sphere to be visible in the alpha? No, I don't think there's a simple way to do that. Maybe what you should do is forget the box, and use a layered shader on the sphere, set up so that is uses a 'Use Background Shader' below the surface, and a regular shader above.