Apple Motion 5.1.1 - Manual (Page 1006)

Chapter 22 Motion tracking 1006
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Predict and Key: If a failure is detected, the tracker predicts the location of the keyframe
based on a vector of the last two keyframes, and continues tracking in the new area.
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Don’t Predict: The tracker remains in its position and searches for subsequent matches as the
clip’s frames progress. While searching for a match, the tracker does not create keyframes.
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Use Existing Keyframes: Use this option if you have manually created track position keyframes
to guide the tracker. After manually adding keyframes, return to the start frame and start the
tracking analysis. If the tracker has difficulty locating the track pattern, the manually created
tracking keyframes are referenced to guide the tracker.
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Color: Click or Control-click the color well to set a new color for the onscreen tracker. You can
also click the eyedropper and select a color in the Canvas. The default tracker color is red.
When a tracker is selected, its center point is yellow and the border of its magnified inset is
the color set in the color well. To adjust the individual color channels, including the tracker’s
opacity, click the disclosure triangle.
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Control Points: When the Track Points behavior references another behavior, such as Analyze
Motion, the Track list parameters are replaced with the Control Point pop-up menus. There is a
pop-up menu for each control point on the shape. From the pop-up menus, choose the track
you want to assign to a control point.
Note: If you add or delete control points to a shape after you apply the reference track,
select the Track Points behavior in Inspector or Layers list to refresh the Control Point pop-up
menu list.
Tip: To check the number of any control point on a shape, you can select the shape in the
Layers list, choose the Edit Points tool from the toolbar, then click on a control point in
the Canvas.
Track controls
The Track parameter behavior lets you track the position parameter of an object (such as a filter,
shape, or particle emitter) to a reference feature of a clip, or to apply tracking data to the position
parameter of an object. The Track parameter behavior can be found in the Behaviors’ parameter
subcategory in the Library, or by choosing Parameter > Track from the Add Behavior pop-up
menu in the toolbar.
For a description of the Tracker Preview, Offset Track, Auto-Zoom, Auto-Zoom Mode, Look
Ahead Frames, and track list parameters, as well as tracker subparameters, see
Analyze Motion
controls on page 994. For information on using the Track parameter behavior, see Track behavior
workflow on page 978.
Parameters in the Inspector
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Source: Drag the source object for the track to this well. The source object can be another
tracking behavior or a footage object. Drag a behavior to the Source well to load that track
into the Track parameter behavior. To clear a Source well, drag the item away from the well
and release the mouse button.
Note: An animated object cannot be used as a source for the Track parameter behavior.
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Action pop-up menu: Choose from a list of tracking data (from other tracking behaviors) in
the project.
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