Mocha planar tracking and mapping

Hi! I’ve actually got a 2 part question. I’ve been working on a video project tracking a face and placing an adobe character animator mask on top of it. After trying to use AE face tracking initially, I’ve settled on using BorisFX Mocha planar tracking for tracking the face in the video. I’ve been able to make it work for some portions of the video so far and here’s a sample of a portion with a successful end result:

trimmed-ae-feedback.2019-06-22 08_31_51.gif

While I’ve been able to handle the character animator portion of it, I’ve had a hard time getting a good plane to track of the face in AE. While it’s mostly usable, there are moments when the perspective swings very far and I’m no longer able to use the planar surface because I get an error that the pixels are too far off screen. Here’s a sample of the tracking that’s not working out well:

facetrack-feedback_2_1.gif

I’ve used AdjustTrack in some portions but this can end up distorting my planar surface. I’d be very ok if the planar surface didn’t track the perspective of the surface as accurately and I atleast had a end result surface that was less accurately tracked but usable.
facetrack-feedback_1_1
Question 1: Is there a way to make a planar tracking surface that tracks perspective/shear/scale a little more loosely so that I can have a final tracked planar surface that is more usable?


Secondly, when I’ve successfully tracked the face’s plane, I end up having to estimate the aspect ratio of the mocha planar surface so that it matches the surface size of the character mask that I’m placing on top of it. While it’s worked out alright, the end result ends up a little off of the intended aspect ratio.

Q2: Is there a way to manually set the aspect ratio of the planar surface (e.g. 16:9) so that I don’t have to eyeball it?

Cheers and thanks for reading my question!

Hi, welcome to the Mocha tracking community!

A1: Faces by their very structure are not planar, so you need to find the most planar bits.
For front-face tracking, I generally recommend tracking the eyes, bridge of nose and up to the hairline. This gives you an overall plane to work with.
The downside to tracking this “plane” is the eyes are very expressive, so eyebrow movement and even blinking may cause issues.
If you don’t care that much about angle to keep the planar region, you could also try just tracking rotation, scale and translation as well.

A2: In Mocha Pro you can set the surface to match the ratio of the insert you’re applying, but sadly not in Mocha AE. The best way around this is to set it exactly how you want it in AE, precompose the layer and then use “Align surface” in Mocha to set the fit shape before pasting the tracking data. We have a guide on how to to this in the user guide.