ADOBE AFTER EFFECTS 7.0
User Guide
334
Stabilize Tracks position and/or rotation to stabilize jerky camera movement or to fix drift of the subject from its
mark. When tracking position, this option creates one track point and generates anchor point keyframes. When
tracking rotation, this option creates two track points and produces rotation keyframes.
Parallel Corner Pin Tracks skew and rotation, but not perspective, using three corner points. Parallel lines remain
parallel, and relative distances are preserved. This option creates three track points (calculating the position of the
fourth) and generates corner point keyframes. The three attach points mark the placement of the three corner points.
Perspective Corner Pin Tracks perspective changes in source footage using four corner points. This option creates
four track points and generates corner-point keyframes. The four attach points mark the placement of the corner
points.
Raw Tracks position. Use this option if the motion target is not available or if you want to apply the tracking data to
it at a later time. All tracking data is stored on the motion source layer within the project. The Edit Target button and
the Apply button are not available with this tracking option. You can also use this option to create tracking data to
use with expressions. This option displays one track point, but you can add others by using the New Track Point
option from the panel options menu.
See also
“About animation and layer properties” on page 188
Motion tracking properties in the Timeline panel (Pro only)
Once you have tracked a feature, After Effects stores the tracking data with the layer in a track.Youcandisplaythis
information by selecting Reveal Current Track In Timeline from the Options menu in the Tracker Controls panel or
by expanding the layer to view the Motion Trackers section in the Timeline panel. You can apply the same tracking
data to different footage or effects. You can also track multiple features in the same footage. After Effects automati-
cally creates a new track each time you choose a tracking option from the Animation menu. Tracks are named
Tracker 1, Tracker 2, and so on. You can rename tracks to help identify them. You can also select tracks and track
points and modify their numeric values.
When you track motion, After Effects adds the following properties to the motion source in the Timeline panel:
Tracker [number] Specifies a track and all track points associated with the track. For example, Perspective Corner
Pinning tracks would list four track points.
Track Point [number] Specifies a feature region, search region, and attach point used in the track.
Feature Center Specifies Position property values for the center of the feature region.
Feature Size Specifies the area of the feature region in pixels.
Search Offset Specifies the distance between the feature region and the search region.
Search Size Specifies the area of the search region in pixels.
Confidence Specifies that accuracy with which the analyzed pixels match those specified by the search parameters.
Attach Point Offset Specifies the distance between the center of the feature region and the attach point.
Attach Point Specifiesthepositionatwhichatargetlayeroreffectisanimatedorattachedtothemotionsourcelayer.
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