Adobe After Effects CS4 User Manual

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USING AFTER EFFECTS CS4

Animation and keyframes

Last updated 12/21/2009

You specify areas to track by setting track points in the Layer panel. Each track point contains a feature region, a search
region, and an attach point. A set of track points is a tracker.

Layer panel with track point

A. Search region B. Feature region C. Attach point

Feature region

The feature region defines the element in the layer to be tracked. The feature region should surround

a distinct visual element, preferably one object in the real world. After Effects must be able to clearly identify the
tracked feature throughout the duration of the track, despite changes in light, background, and angle.

Search region

The search region defines the area that After Effects will search to locate the tracked feature. The tracked

feature needs to be distinct only within the search region, not within the entire frame. Confining the search to a small
search region saves search time and makes the search process easier, but runs the risk of the tracked feature leaving the
search region entirely between frames.

Attach point

The attach point designates the place of attachment for the target —the layer or effect control point to

synchronize with the moving feature in the tracked layer.

Note: When you begin tracking, After Effects sets the quality of the motion source layer to Best and the resolution to Full
in the Composition and Layer panels, which makes the tracked feature easier to find and enables subpixel processing and
positioning.

After Effects uses one track point to track position, two track points to track scale and rotation, and four points to
perform tracking using corner pinning.

Online resources for motion tracking and stabilization

Curtis Sponsler provides detailed instructions and explanations for tracking and stabilizing motion in a PDF excerpt
from his book

The Focal Easy Guide to After Effects

Chris and Trish Meyer provide a video tutorial on the

ProVideo Coalition website

that demonstrates and explains the

basics of motion tracking.

Angie Taylor provides a tutorial on the

Digital Arts website

that shows how to use tracking data and the Clone Stamp

tool to apply copies of an object in a scene while matching a camera move.

Michele Yamazaki provides a tutorial on the