I have a 4 point plane (quadratic) that I would like to use as a mask when rendering.I need this so the mask will be transformed correctly when I move the camera. This plane is covering the area I would like to mask.
I was thinking to maybe render a mask scene and feed that into the final scene as a mask. But since Blender now has masks, it would be easier if we could convert a mesh into a mask.
**EDIT I'm using Blender 2.68a with Cycles.