Object Occlusion Issues Using Mocha AE

[Ethan Ramos]

Hi there,

I am trying to track and screen replace screens in two scenes using Mocha AE.  Both of them where the camera is zooming out from a screen (TV/Computer).  However there are people that walk in front of these screens as well. I have tried using manual track on the portions where the person walks in front of the TV but it appears to throw off all the surface data and tracking data before it. Any advice on how I would track the TV/Computer would be great.  I cannot seem to get a proper track with the occlusions happening.

Clips I am trying to track
CLIP 1:
https://drive.google.com/file/d/11Wxw85VS68xXIMHlreK216gmkAKN4_eu/view?usp=sharing
CLIP 2:
https://drive.google.com/file/d/1WBxp3oVXhrlbBSeBjwECEQqmKFTLnM_V/view?usp=sharing  

[Mylenium]

The whole tracking setup is basically wrong since you have not placed additional reference markers outside the screen. that's why you also run into these massive issues as soon as someone enters the frame. Some off-object markers would at least allow you to stabilze those segments and possibly facilitate manual tracking. And of course one of the cardinal rules with such stuff is that you avoid dollies and zooms like the plague and crop the frame in post if possible. As it is there's really not much you can do but chew through it one frame at a time and manually matchmove as best as you can. There's just not enough to latch on for mocha even if you use exclusion layers and other fancies.

Mylenium

[Rick Gerard]

For shots like those samples, I would split the layers everywhere that the tracking starts to fail. Then I would track each section in Mocha AE and use Corner Pin or my Stabilize Corner Pin workflow to get things to work. 

The first clip is pretty easy. You just have to manually track a couple of sections and set a few keyframes using adjust track.

The second will take some more work and require a few frames of Hand Roto, but it can certainly be done using the Stabilized Power Pin workflow I demonstrate in this tutorial:

I'm guessing about an hour to track and roto the first clip and maybe two or three for the second one. If both shots had been planned and directed a little better the total time to track and roto could be reduced to under a half hour per clip.