[planar tracking] Make a mask to cut out a person

Hello!

I have some footage of a person walking on some ground:


I want to create this: (kinda like she's on a desert)

(this is actually what I got, but for a few frames lol)

So in fusion, I used planar tracking to create a mask, tracked it and used the same media IN to cut her out and put her in the foreground using a simple merge.


(here the input of the planar tracker had the fast noise "cloud" which made it worse, i fixed that later)

This kinda works, but of course the tracking is not perfect! And I can't for the life of me (I just started using Resolve) figure out how to improve the tracking.

At a certain point she turns a bit and that messes the whole thing:


And if I adjust the spline in certain frames it stays that way.

So, what do you recommend I do? tips? help?

Thanks!

Unfortunately the Planar Tracker is probably not the tool for this, it assumes the object is flat and non-deforming and therefore will fail if the object turns out to be 3D and deforming. You could try the new magic mask in Resolve and augment it with additional masks, warps etc.. but I think the reality of this is it any solution will require hand a reasonable amount of roto work. You may also get away with keying on the shadowed components.

At the very least, you won't get away with a single rotoshape for an entire person. Break it apart into shapes that move together: The head, each upper arm, each lower arm, the left side of the torso, right side of the torso.

With that pose, you might be able to get away with doing the arms as a single piece, but even if the arms are pretty stiff, there may still be some flexion that the planar tracker won't pick up.

Apply the planar transform to an independent rotoshape to give yourself more control over it. Being able to divorce the shape from the underlying tracking info can help.

Fusion's planar tracker may or may not be successful. I don't really have a lot of experience with it, so I couldn't say.

Apply the planar transform to an independent rotoshape to give yourself more control over it. Being able to divorce the shape from the underlying tracking info can help.

Besides breaking up the shape, this is one of the most important aspects of planar track usage imho. Shape which encloses the region for tracking and the shape(s) this produced transform drives do not have to be the same.

Unfortunately the Planar Tracker is probably not the tool for this, it assumes the object is flat and non-deforming and therefore will fail if the object turns out to be 3D and deforming.

Thanks. This clears up a lot, lol. I guess I expected it to be kinda magic or something. Like you say, this may require manual masking and keying, old fashioned rotoscoping. Another thing I don't like about the mask this generates is that I have no control over the mask like feathering, edges, etc.

At the very least, you won't get away with a single rotoshape for an entire person. Break it apart into shapes that move together: The head, each upper arm, each lower arm, the left side of the torso, right side of the torso.

Ah, this is a good idea! thanks! maybe I'll try that and see if I have better results

Shape which encloses the region for tracking and the shape(s) this produced transform drives do not have to be the same.

I see... thanks guys for clearing this up.

I ended up manually masking using a spline, frame by frame. Luckily the clip is only a couple of seconds long so it didn't take me too long:


I'm happy with the result! It's not Hollywood material but it does the job for now


Thank you guys for your help!

Works really nicely for the shot, did you turn motion blur on in the Mask?

Works really nicely for the shot, did you turn motion blur on in the Mask?

Nope! Just softened the edges a very tiny bit.