Is it possible to make a mask follow motion tracking key frames? I've got some footage of a door-frame, which I'm making into kind of portal. I've made a separate layer, which I've adjusted the brightness and color balance and then masked with a large feather around the edges of the door, to make it look like light coming out of the portal. Later on in the shot the camera pans a bit to the side. I'd like to motion track it and make the mask move with the door-frame if that's possible. I know if I animate the mask by hand, it'll be really hard to get it to match up perfectly. So is this possible. Also, I'm using After Effect 7.
(Mathias_Möhl), Mar 12, 2009 5:38 AM
>Is it possible to make a mask follow motion tracking key frames?
Not really. If you check AEnhancers.com you will however find a few scripts attempting to mimic this behavior by post-applying tracker data to masks. The one thing that they have in common is that they are slow to do their work (with a certain number of keyframes) and are far from intuitiv to use. In your case I don't see the problem, though. You could just as well use a conventional Corner Pin track, just with the minor variation that you apply it to a layer (solid) that acts as a matte on your other footage...
Just because you can't apply data directly to a mask doesn't mean a separate layer can't be utilized to control the mask position/scale/rotate.
You can apply your tracking data to an adjustment layer and then mask on that. I often use this for rotoscoping;
Start you mask and track on the same frames, track the layer first and then apply that data, draw your mask (it already follows your object!), transform and reshape your mask as needed. With Mocha tracker this is much more powerful than normal Adobe tracker. Delete anchor point keyframes from the Mocha track and reset the anchor before masking.
For additional control, paste the track data onto a null, parent the adjustment layer with the mask to this and gain a very handy offset axis on adjustment layer to blend your track.
Take a look at this tutorial -
I've little doubt you'd be able to 'modify' the outcome to suit your own needs. It takes a little while to wrap your head around but it is helpful in the extreme.
> If you check AEnhancers.com you will however find a few scripts attempting to mimic this behavior by post-applying tracker data to masks. The one thing that they have in common is that they are slow to do their work (with a certain number of keyframes) and are far from intuitive to use
In my opinion this is not the case for tracker2mask.
Here you find some video-tutorials based on which you can judge yourselves: