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Tracking a moving region or object (PB only)
For best results, first prepare the object or region you are tracking before you begin
filming. Because The Tracker/Stabilizer compares pixels from one frame to the next to
produce an accurate track, attaching high-contrast markers to the object or region lets
After Effects more easily follow the motion from frame to frame. Lightweight, brightly
colored balls, such as Ping-Pong balls placed on the feature, work particularly well to
preserve the shape of the track point. The number of markers you use corresponds to the
number of points you are tracking.
If you are not able to attach markers, choose a high-contrast region or object.
To track a moving region or object:
1 Select the motion footage layer you want to track and open it in a Layer window. You
must have at least two layers in the Composition window.
Note: The Tracker/Stabilizer can track either an original motion footage layer or a precom-
posed layer that includes additional effects or other properties in the composition.
2 In the Layer window menu, choose Tracker/Stabilizer Controls.
3 In the Track and Stabilize section, click the Type pop-up menu and choose one of the
following:
Choose Track to track the motion of a layer.
•
Choose Affine Corner Pin to track three points in a motion footage layer.
•
Choose Perspective Corner Pin to track four points in a motion footage layer.
•
4 Next to the Type pop-up menu, select either the Position or Rotation box, or both,
depending on what you want to track.
5 In the Tracker panel, specify the work area you want to track by dragging the In and Out
points to the desired locations.
6 Drag the current-time marker to the point you want tracking to begin.
7 Define the feature region, search region, and track point, as described in "Defining
tracking regions (PB only)" on page 307.
8 Click Options to specify the second layer or effect and to define other tracking settings,
as described in "Defining tracking settings (PB only)" on page 308, and then click OK.
9 In the Tracker panel, click Analyze. Watch the tracking to make sure it is accurate. If not,
press any key to stop the tracking, and then correct the problem as described in
"Correcting a drifting feature region (PB only)" on page 314. A black line appears in the
time bar, indicating the portion of the layer that has been tracked. Keyframes are not
generated until you click Apply.
10 To track multiple areas in the same layer, repeat steps 3 through 8 for as many areas as
you need. If you track a previously tracked area within the same track type, After Effects
generates new track data for the area.
11 When you are satisfied with the track, click Apply to generate keyframes for the
selected layer or effect point control you are attaching.
Using Help | Contents
Using Property and Tracking Controls (PB only)
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