I have planar tracked base footage with some effects layers over the top, and I have a duplicate of the base footage over the effects layers. I'm trying to mask in select portions of the duplicate base footage to lay over the effects layers. I've tried placing a plane on the top layer, setting it to 3D and parenting it to one of my track points, then added a [Set Matte] effect to the duplicate base footage with the source layer set to the top plane and the Matte Source set to Alpha. My mask stays positioned correctly, but does not expose the underlying footage, it only exposes the plane's base color. I'm new to HitFilm and still learning the interface. If anyone has any suggestions, I sure would appreciate any suggestions.