Apple Motion 4 - Manual (Page 1265)

The foreground element is “pinned” on the background element.
Note: In this example, a reflection is created on the table using a duplicated and
transformed copy of the tracked image.
To fine-tune the track (when Four Corners is chosen from the Type pop-up menu), you
may need to make minor adjustments to the foreground element, such as modifying its
scale or rotation. When you choose the Attach to Source option from the Transform
pop-up menu in the Behaviors tab of the Inspector, you cannot transform the tracked
object. To transform the tracked object, choose Mimic Source from the Transform pop-up
menu.
5 To transform the foreground element after the tracking data has been applied:
a Choose Mimic Source from the Transform pop-up menu in the Behaviors tab of the
Inspector.
b Click the Properties tab in the Inspector and make the necessary adjustments using
the Scale, Rotation, and other parameters.
For more information on the Mimic Source and Attach to Source transform options, see
Match Move Controls .
Option 2: Corner-Pin the Object Before Tracking
In this workflow, a foreground object is pinned to a background picture frame using the
Four Corner parameter in the Properties tab prior to applying the Match Move behavior.
To adjust the four corners of an element and then corner-pin the element
1 Select the foreground element you want to corner-pin.
1265 Chapter 19 Motion Tracking