Apple Motion 4 - Manual (Page 1319)

Align Tangents: When this checkbox is deselected, tangents remain aligned at their
original angles. When the checkbox is selected, the tangents match the transformation
of the source animation, and the shape changes its form.
Movement: The Movement parameters contain the Analyze and Reverse parameters.
This parameter appears only when there is a tracking source (footage) in the source well.
• Analyze: Click the Analyze button to begin the motion tracking analysis. Once Analyze
is clicked, a status window appears that displays the tracking progress. To stop the
analysis, click the Stop button in the status window or press Esc.
The start of the track is based on the current playhead position, rather than the start
of the behavior in the Timeline.
• Reverse: When the Reverse checkbox is selected, the clip is analyzed from the current
playhead position to the first frame of the clip (or the first frame of the tracking
behavior).
Note: You must move the playhead to the frame where you want to begin the reverse
analysis.
Tracker Preview: This parameter appears only when there is a tracking source (footage)
in the source well. This preview area provides a magnified view of the tracking reference
area for the selected tracker. The preview updates as you adjust the position of the tracker
in the Canvas. You can also drag in the preview area to adjust the position of the tracker.
When dragging in the preview area, the image moves around the red crosshairs in the
preview and the tracker moves in the Canvas.
Offset Track: This parameter appears only when there is a tracking source (footage) in
the source well. If a tracker’s reference point becomes temporarily hidden or goes off the
screen, this parameter allows you to select a different reference point that continues the
same tracking path as the original reference point. For more information on offset tracking,
see
Tracking Obscured or Off-Frame Points .
Auto-Zoom: This parameter appears only when there is a tracking source (footage) in
the source well. Choose an option from this pop-up menu to set the magnification level
when positioning the tracker in the Canvas. This allows you to zoom in on the Canvas
when searching for an ideal tracking reference pattern. There are four choices:
• None: When moving the tracker in the Canvas, there is no magnification (only the
tracker appears).
• 2x: When moving the tracker in the Canvas, the magnification around the tracker is
two times the normal zoom level.
• 4x: When moving the tracker in the Canvas, the magnification around the tracker is
four times the normal zoom level.
• 8x: When moving the tracker in the Canvas, the magnification around the tracker is
eight times the normal zoom level.
1319 Chapter 19 Motion Tracking