I have created a clock face. I have two shape layers; one for the clock face (plain circle), and another for animated clock hands that spin around. The animated clock hands are white, and I've applied the "Alpha Inverted Matte" to the clock face...so the end result is a clock face with negative space hands spinning around. This works fine.
Now, I'm trying to make the whole comp 3d, using the Cinema 4D renderer and extruding via the geometry options. The problem is...once I change to the C4D renderer, the track matte does not work. I just see the clock face - no hands. I'm really keen to see the negative space clock hands spinning around on an EXTRUDED object. It will be a great effect. Is there a way to achieve this?
Track mattes are disabled in the Ray-tracing Renderer and in the CINEMA 4D Renderer. That's because track mattes are a pixel operation, but true 3D comps think in terms of geometry, light and materials instead of pixels.
To get the effect you want, you should put the circle and the clock hands in the same shape layer. Use groups to control the transforms for the rotations and use Merge Paths set to subtract mode to knock the hands out of the circle. When you extrude this more complex shape layer, you'll get the negative space you describe.