Apple Motion 4 - Manual (Page 1325)

Fail Behavior: This pop-up menu specifies what happens if the track confidence value
falls below the Fail Tolerance amount. The following options are available:
• Smart Retry: The tracker attempts to find the reference pattern in a larger search area.
If the pattern cannot be found, the tracker switches to the Predict option. Smart Retry
is the default fail behavior.
• Stop: Stops the analysis when the tracker loses the reference pattern. You can also click
the Stop button in the tracking progress dialog or press Esc to stop an analysis.
• Predict: The tracker predicts a new search area without creating keyframes until it finds
a match for the reference pattern. This is excellent for tracked objects that pass behind
foreground objects.
• Predict and Key: If a failure is detected, the tracker predicts the location of the keyframe
based on a vector of the last two keyframes, and continues tracking in the new area.
• Don’t Predict: The tracker remains in its position and searches for subsequent matches
as the clip’s frames progress. While searching for a match, the tracker does not create
keyframes.
• Use Existing Keyframes: Use this option if you have manually created track position
keyframes to guide the tracker. After manually adding keyframes, return to the start
frame and start the tracking analysis. If the tracker has difficulty locating the track
pattern, the manually created tracking keyframes are referenced to guide the tracker.
Color: Click or Control-click the color well to set a new color for the onscreen tracker.
You can also click the eyedropper and select a color in the Canvas. The default tracker
color is red. When a tracker is selected, its center point is yellow and the border of its
magnified inset is the color set in the color well. To adjust the individual color channels,
including the tracker’s opacity, click the disclosure triangle.
Tracker pop-up menu: When the Track Parameter behavior references another behavior,
such as Analyze Motion, the Track list parameters are replaced with the Tracker pop-up
menu. Select the tracker you want to apply from the referenced tracking behavior to the
position parameter of the affected object from this menu.
Apply To: Click the Go pop-up menu to select a different parameter to apply the track.
For example, if the Track parameter is applied to the X Position parameter of the tracked
object and you want to apply the data to the X and Y Position parameters, click Go and
choose > Properties > Transform > Position > X and Y.
HUD Controls
The Track parameter HUD contains controls to load a tracking behavior into the behavior
(via the Source Behavior well or the tracking behaviors pop-up menu), to specify how
the position parameter moves, to start the motion analysis (the Analyze button), to reverse
the direction of the track (the Reverse checkbox), and to offset the track (the Offset Track
checkbox).
1325 Chapter 19 Motion Tracking