Apple Motion 4 - Manual (Page 1264)

2 In the Behaviors tab of the Inspector, choose Four Corners from the Type pop-up menu.
Note: The Four Corners option is not available when Match Move is applied to a 3D group.
To corner-pin a 3D group, select the Flatten checkbox in the Group tab of the Inspector.
In the Canvas, a tracker appears at each corner of the foreground object’s bounding box.
In the Inspector, the default track list (Anchor and Rotation-Scale), is replaced with the
Top Left, Top Right, Bottom Right, and Bottom Left trackers.
3 In the Canvas, drag each tracker to a “corner” of the background element (in this example,
the corners of the picture frame provide the four-corner track points).
As with the Analyze Motion trackers, a magnified inset appears in the Canvas as you drag
the trackers.
4 Click the Analyze button in the HUD or Behaviors tab of the Inspector.
1264 Chapter 19 Motion Tracking