Region of interest in GMaskTracer

The title says it all. I have a nice key but I want to keep some parts of the image. It’s real easy to mask the areas I want to keep because I have a tracked camera.

We have all the blend modes and matte composition and correlation, but can’t make sense of it.

On a related note, is it possible to make a mask to just subtract from another one without affecting the matte?

I think using different outputs will give you what you’re asking for. It works just like in Action. You can use Alt-E to select/de-select which masks you want to assign to an output and then you can use Comp nodes to Multiply/Add/Subtract the mattes how you want.

Sure we can do it downstream, set contexts, etc, but there should be an easier and intuitive way to do it in one node.

I think this video is explaining it:
Indeed with substract blending mode.

Thanks but I believe Sinan is looking for to solve this in Gmask Tracer.

Can you post an example because I’m certain this is possible in gmask tracer.