Apple Shake 4 - Manual (Page 733)

Chapter 25 Image Tracking, Stabilization, and SmoothCam 733
The second strategy is to use the Offset Tracker button (in the Viewer shelf ). When the
reference pattern becomes obscured, turning on the Offset Tracker button lets you
move the tracking control, picking a new reference pattern and search region in a
different area from the original reference pattern. The offset between the original
reference pattern and the new one is calculated in order to maintain continuity in the
resulting track path.
In the following example, the track is obscured by a lamp post, so the search region
(not the point, just the region) is moved to a nearby pattern and tracking continues
until the original pattern reappears. Even though one region is examined, the points
are saved in another region. The second tracking pattern should travel in the same
direction as your original pattern.
Modifying the Results of a Track
A track can be modified in several ways to massage the data from a less-than-perfect
track. You can manually modify a track in the Viewer or in the Curve Editor, average
tracks together, smooth tracks to remove noise, or remove jitter to smooth out a
camera movement.
Manually Modifying Tracks
To manually adjust a tracking point onscreen, turn on the Autokey button in the
Viewer shelf.
Note: To add a keyframe without moving an onscreen control, for example, to create a
keyframe at frame 20 with the same value as a keyframe at frame 19, turn Autokey off
and then back on.