5.5

1146Motion User Guide
As with all behaviors, you can drag or copy (by Option-dragging) a Track Points
behavior to a new shape in the Layers list. When you apply the behavior to a new shape,
the trackers are applied to the control points of the new shape. If the new shape has
more control points than the originally tracked shape, only the original track points are
applied. For example, if the originally tracked shape has three control points, and the
new shape has five control points, trackers are applied to the first three control points
of the new shape. If the new shape has fewer control points than the originally tracked
shape, trackers are applied to the existing points on the new shape.
Note: Paint strokes usually have a large number of control points. Simplify a paint stroke
by deleting or disabling control points before applying a Track Points behavior to the
stroke. To track the stroke as a whole, rather than by its control points, use the Match
Move behavior. For more information about paint strokes, see Intro to paint strokes
in Motion.
Apply the animation of one shape to the control points of another shape
Applying the animation of one animated shape to another is an easy way to create fun,
complementary animations in which the objects appear to play with each other. For this
workflow, your project must contain an object animated with keyframes or behaviors.
1. In a Motion project that contains two shapes, animate one of the shapes using
keyframes or a Basic Motion behavior.
In this example, a simple line shape is animated with the Spin behavior.
For more information about animating with keyframes, see Intro to keyframing in Motion.
For more information about Basic Motion behaviors, such as the Spin behavior, see Intro
to basic Motion behaviors.
2. In the Layers list, select the nonanimated shape, then click Behaviors in the toolbar and
choose Shape > Track Points.
Note: When you apply the Track Points behavior to a simple shape, a dialog appears.
Click Add to convert the shape’s geometry to control points.
3. Drag the animated shape from the Layers list to the Track Points behavior’s Source well
in the Behaviors Inspector.
Note: If the nonanimated shape is positioned immediately above the animated shape
in the Layers list when the Track Points behavior is applied, the animated shape is
automatically used as the Track Point behavior’s source.
A thumbnail of the animated object appears in the Source well of the Track Points
Behaviors Inspector.
4. In the Behaviors Inspector, click the Transform pop-up menu, then choose Attach
to Source.