Mocha is likely the definitive visual effects tool, letting users track shots easily. Even if you have never tracked anything before, you can get up to speed in mocha fairly quickly, tracking some complex shots without too much trouble. There will always be some shots that will give some trouble though. What if the thing you are tracking leaves the screen? What if it camera is continually tracking or panning? Mocha has a thing for that: Unlink tracking.
one of the most simple and powerful techniques for using Mocha’s planar tracker to track camera movement: Unlink Tracking
With a short tutorial Imagineer Systems shows how you can easily track shots using the Unlink track feature in Mocha products. Unlink tracking separates the tracking data from the shape data. In simple terms, the tracking shape can stay on the screen in one place, while the tracking data will read the correct camera move. This can be a great technique for when things leave the screen.
The tutorial covers how to identify the problem and when Unlink Tracking can be a suitable solution. It also covers how to handle issues when the tracking slips, and for what situations unlink tracking is not a great solution.