Planar Track occlusion

I have a clip for which I have roto that was sent out. Wondering if there is a way to use that roto as an occlusion for a planar track within gmask tracer or anywhere honestly. on 2020.3.2 MacOS

Hrm…I was under the impression that you had to have live gmasks and then use “Media Gmasks” in the “Exclusive” under Analysis Constraints within the Gmask Tracer’s Tracking Menu.

If you have an existing matte, comp black into the front using a comp node and try to Planar Track that? Bass ackwards, but, might work.

Yeah, I figured having live gmasks was the only way but I figured I’d give it a shot.

@Jeff am I right? Can you feed Gmask Tracers / Gmask objects in Action a prerendered matte for exclusion?

I’m thinking you’re right Randy, in that you can’t do what Dino is asking. My preface for my response here is that I don’t rely heavily on Flame’s tracking holdouts so I may be missing something. When a track I run into is complicated enough for me to start to think about holdout mattes, I usually hop on over to Mocha. It could be that I’ve just spent a lot more time with it, but I find Mocha’s holdout system to be a bit more intuitive and flexible.

To second the workflow Randy mentioned, I think it would work if you were to use a gmask tracer to track your roto. It seems crazy but the nature of a holdout matte definitely allows for it to not be perfect, although I can think of a few circumstances where the roto isn’t easy to track. If you ARE able to track it though, once you have that live gmask tracer, you can do exactly what you’re looking to do.

A quick look into Action’s / Gmask Tracer’s exclusion settings though tells me that it seems to clearly only work with live gmasks that exist inside the Action / Gmask Tracer in question. I think that must be why they’ve specifically labeled the drop down “Media Gmasks”. It looks like if you’re looking for holdouts to work with external media, you’re in feature request territory, but I think if that feature were to be implemented, it would get a little complicated.

In your use-case you’re using a matte from another source, so you’re limited to only being able to use Action, since Gmask Tracer can’t have multiple inputs. You’d probably have to specify which input (media) was holding the holdout matte, which is separate from the media the node is using as its basis for tracking (the “Use Media” field). I can wrap my head around how something like that would work, but it sounds like it might not be a quick one for the devs to pump out. As usual it would boil down to just how many people are looking for something like that.

What if you just use your roto to comp the tracked clip over black and track that, thereby obliterating anything the tracker might find interesting? I’m not sure that’s algorithmically the same as it loading the matte properly as a holdout, but even though it feels trashy it might be worth a shot?