Effective Motion Tracking

Effective Motion Tracking

There is more that can be done with tracking than

simply sampling the motion of one layer and applying it

to another, even though that’s fundamentally what it does;

because you can track in several different ways using a variety

of points, the methods and applications go far beyond

the obvious.

Native tracking possibilities have been further expanded in

After Effects CS4 thanks to the licensing and inclusion of

MochaAE from Imagineer Systems. Previously available as

a third-party application, Mocha uses a fundamentally different

approach (planar tracking) than that of the built-in

After Effects point tracker and it solves a problem (corner

pinning) that had exposed weaknesses in that tracker.

It is also possible to use third-party 3D tracking software to

import 3D camera data matched to real-world motion into

After Effects, via a methodology that is described at the

end of this chapter.

All of these automated trackers are astoundingly accurate,

often sampling motion at a detail level that would be impossible

for you to pick up by eye. It’s not a fully automated

process, however, and so you must understand how to

. Choose effective track regions

. Customize settings based on the particular scene

. Rescue tracks that seem to have gone astray (or

abandon and restart, provided you understand what

to try instead)

. Handle motion blur

This chapter addresses these techniques and more. Once

you grasp these, you can use tracking to go beyond the

ordinary:

. Match multiple elements to a single track using the

3D camera

. Stabilize a handheld or other moving camera shot

. Continue tracks when the object being tracked leaves

the visible frame

. Import and use 3D tracking data

There are so many cases where effective tracking can help

accomplish the seemingly impossible; it’s worth knowing

this stuff inside out.