5.5

1148Motion User Guide
Track a filter’s position parameter in Motion
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 adjustable controls in the Track behavior, see Track controls
in Motion.
Track the parameter of a filter
1. Apply a filter to a layer in your Motion project.
See Apply or remove filters in Motion.
2. In the canvas, drag the center point of the filter to the region of the layer (a video clip or
animated shape) you want to track.
3. 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’s 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 in Motion.
4. Click the Analyze button in the Behaviors Inspector or HUD.
The filter’s center is tracked to the clip. You can make changes to the filter parameters
after the analysis is performed.