I have a comp with a lot of layers that need to reference different mattes. Rather than throw a track matte above every layer or create a bunch of precomps, which would be cumbersome, I would like to set the matte with an effect. Set Matte works fine for 2d layers, but for 3D layers, the matte doesn't like up correctly, even with Stretch Matte to Fit checked off.
Does anyone know of a 3rd party plugin or expression that works like set matte, but with 3D layers?
There can be no such thing since that's not how AE's rendering pipeline works. Any tool to that effect would need to completely replace the native 3D layers. That of course in a way already is possible using respective commercial plug-ins that handle the 3D stuff internally and the result is just a 2D effects buffer...