ADOBE AFTER EFFECTS 7.0
User Guide
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An X appears in the Layer panel at the center of the feature region at each keyframe.
3 To adjust the motion path, do any of the following in the Layer panel:
• To move the entire track point (feature region, search region, and attach point) at a particular keyframe, drag a
keyframe marker with the Selection tool.
• To adjust the speed, use standard techniques for modifying motion paths.
• To adjust the track point, display that frame in the Layer panel, and use the Selection tool.
See also
“About motion paths” on page 210
To set tracker confidence actions (Pro only)
As an image moves in a shot, the lighting, surrounding objects, and angle of the object can all change, making the
once-distinct feature region difficult to track confidently. After Effects reports the confidence of the motion tracking
through the track point’s Confidence properties in the Timeline panel. You can make the tracking stop, continue,
adapt, or extrapolate motion when the confidence value falls below a specified threshold.
1 Select a tracker in the Timeline panel, and click Options in the Tracker Controls panel.
2 Specify the lowest confidence threshold that is acceptable to you in the If Confidence Is Below text box. When the
track point’s confidence level is below the value you specify, After Effects performs the action you specify.
Note: To determine an acceptable confidence threshold, track the motion and then examine the Confidence values
displayed in the Timeline panel for problematic frames. Specify a confidence value that is slightly larger than the largest
confidence value for the problematic frames.
3 Choose the action that you want to occur while the confidence level is below the specified percentage value:
Continue Tracking Ignores the confidence level and continues tracking. This is the default behavior.
Stop Tracking Stops the motion tracking.
Extrapolate Motion Estimates the position of the feature region. Attach point keyframes aren’t created, and attach
point keyframes on the low-confidence frames from previous tracks are deleted. If the confidence level rises above
the specified threshold on a subsequent frame, After Effects interpolates the motion of the attach point on the low-
confidence frames.
Adapt Feature Uses the original feature region until the confidence level falls below the specified threshold. At that
point, After Effects adapts the feature region to the frame preceding the one that has low confidence and continues
tracking. This option isn’t available if Adapt Feature On Every Frame is selected in the Motion Tracker Options
dialog box, since enabling feature adaptiveness causes After Effects to adapt the feature region with every frame
regardless of the confidence level.
About corner pinning (Pro only)
Most tracking options track a single feature in a motion layer. This single feature determines the position keyframes
that are used to animate the anchor point (or center) of the target layer. Unlike standard tracking, the corner pinning
options track points that are used to animate the corners of a typically rectangular target layer. Corner pinning is
useful for adapting the target layer within a specified area of the motion layer. For example, you can track four
cornersonthesideofamovingbustoattachabillboard.Cornerpinningoptionsallowyoutoeitherskewthetarget
layer or simulate a change in perspective. The attach points, not the feature regions, determine the placement of the
target layer’s corners. By default, the attach points are centered within the feature regions.
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