Apple Motion 5.1.1 - Manual (Page 978)

Chapter 22 Motion tracking 978
Note: By default, Mimic Source is chosen from the Transform pop-up menu. For more
information on the Transform pop-up menu, see
Track Points controls on page 1003.
Track behavior workflow
The Track behavior (in the Parameter category of behaviors) lets you track a position parameter
of an object. For example, you can track the center of a Light Rays filter to a moving light in a clip.
Note: This behavior applies only to filters with position parameters, such as Scrape, Ring Warp,
Light Rays, Slit Tunnel, and so on.
For a full description of the Track behavior, see Track controls on page 1006.
Apply the Track behavior to a filter
1 In the Canvas, position the center point of the filter over the reference pattern.
In this simple example, the center point of a circle blur is positioned over the license plate of
a car.
2 In the Filters Inspector, Control-click the Center parameter, then choose Add Parameter Behavior
> Track from the shortcut menu.
In the Canvas, the filter’s onscreen control is replaced with a tracker. The Behaviors Inspector
becomes active, and the Track behavior parameters are displayed.
Note: In the Filters Inspector, a behavior icon (a gear) appears next to the Center parameter,
indicating that it is influenced by a behavior.
If necessary, adjust the tracker in the Canvas. If the reference pattern you want to track is offset
from the center of the filter, use the Offset Track checkbox. For more information on using the
Offset Track parameter, see
Track obscured or off-frame points on page 988.
3 Click the Analyze button in the HUD or Behaviors Inspector.
The filter’s center is tracked to the clip. You can make changes to the filter parameters after the
analysis is performed.
Adjust onscreen trackers
The Analyze Motion, Stabilize, and Match Move behaviors share common onscreen and Inspector
controls. Each track is represented by a single onscreen control—the tracker.
The default onscreen tracker color is red. Depending on the color of your subject, you might
need to change the color of the tracker to see the tracker in the Canvas.
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