Tracking a turning card that turns 180

New to Mocha. I’m using Mocha Pro plugin in Resolve 15b6
I am tracking a card, essentially a 4 corner pin track.
The card turns and at some point is completely turned sideways.
I can track it up to a point where there is too much motion blur.
Then I use Adjust track to manually set the 4 corners.
However when the card turns sideways Adjust track becomes unstable.
What is the best way to deal with this, when the tracked surface turns completely?

thank you.

Hey George,

First of all, I should point out that the OFX version of Mocha Pro isn’t currently supported properly in Resolve 15, but i’m glad to hear you’re getting it to work for you!

Now, onto the exact problem:
Because of the planar nature of the tracker, when there is no longer a plane to track, it becomes very difficult to latch onto anything useful.
Adjust track should be able to handle moving the corners, but AdjustTrack is designed for sublte movement changes to correct drift, so any large changes might be affecting it.

My suggestion would be to track it as best you can up to a point where you’re losing the track, then switch to Manual Track where you’ll be able to do hand-keyframed changes to the actual tracking data using the surface.
Be sure to be on v5.6 for this however, as we fixed a number of manual-track related bugs in that version.

Without seeing the actual clip of course, it’s hard to suggest anything further.

Thanks Martin,

its just rectangular card that turns completely sideways.

Help me please understand what I need to manually adjust to get the tracking data up to the point where the surface is almost completely turned sideways.

I can keyframe the tracking polygon manually for the few frames where automatic tracking is not possible. But these keyframes don’t transform the surface or generate tracking data.

Is there another way to manually keyframe the surface transformation other than Adjust Track?

Yes, you need to use the option “Manual Track” in the track module parameters. This will allow you to keyframe the surface directly.

See here if you need help on how Manual Track works:

Thank you.
When to use manual track and when adjust track?
What is the difference?
Could you point me to a tutorial?

We don’t have a comparison tutorial, but that’s a good idea. Manual track is for getting past occlusions and other untrackable areas, adjust track is for correcting a track slipping.