Adobe AFTER EFFECTS CS3 PROFESSIONAL User Manual page 344

Note: If the layer that you're attaching has motion blur enabled, make sure that the Shutter Phase value is set to -1/2
times the Shutter Angle value. This centers the motion blur on the attach point. Otherwise, the attached object may
appear to lead or lag the object that it's attached to.
See also
"Use motion blur" on page 202
Motion tracking controls
You set up, initiate, and apply motion tracking with the Tracker Controls panel.
The layer that contains the motion to track.
Motion Source
Note: Layers are available in the Motion Source menu if they have source footage items that can contain motion or if
they are composition layers. You can precompose a layer to make it available in the Motion Source menu.
The active tracker. You can modify settings for a tracker at any time by selecting the tracker from this menu.
Current Track
The tracking mode to use. The motion tracking itself is the same for each of these modes; they differ in
Track Type
the number of track points and how the tracking data is applied to the target:
• Stabilize tracks position, rotation, and/or scale to compensate for movement in the tracked (source) layer. When
tracking position, this mode creates one track point and generates Anchor Point keyframes for the source layer.
When tracking rotation, this mode creates two track points and produces Rotation keyframes for the source layer.
When tracking scale, this mode creates two track points and produces Scale keyframes for the source layer.
• Transform tracks position, rotation, and/or scale to apply to another layer. When tracking position, this mode
creates one track point on the tracked layer and sets Position keyframes for the target. When tracking rotation,
this mode creates two track points on the tracked layer and sets Rotation keyframes for the target. When tracking
scale, this mode creates two track points and produces Scale keyframes for the target.
• Parallel Corner Pin tracks skew and rotation, but not perspective; parallel lines remain parallel, and relative
distances are preserved. This mode uses three track points in the Layer panel—and calculates the position of the
fourth—and sets keyframes for four corner points in a Corner Pin effect property group, which is added to the
target. The four attach points mark the placement of the four corner points.
• Perspective Corner Pin tracks skew, rotation, and perspective changes in the tracked layer. This mode uses four
track points in the Layer panel and sets keyframes for four corner points in a Corner Pin effect property group,
which is added to the target. The four attach points mark the placement of the four corner points. This option is
useful for attaching an image to an opening door or the side of a bus that's turning a corner.
• Raw tracks position only. Use Raw to generate tracking data that you won't apply using the Apply button. For
example, you can copy and paste the keyframes for the Attach Point property to the Position property for a paint
stroke; or, you can link effect properties for the Stereo Mixer effect to the x coordinate of the Attach Point property
using expressions. Tracking data is stored on the tracked layer. The Edit Target button and the Apply button are
not available with this tracking option. You can add track points to a tracker by choosing New Track Point from
the Tracker Controls panel menu.
The layer or effect control point that the tracking data is applied to. After Effects adds properties and
Motion Target
keyframes to the target to move or stabilize it. Change the target by clicking Edit Target. No target is associated with
a tracker if Raw is selected for Track Type.
Begins the frame-to-frame analysis of the track point in the source footage:
Analyze buttons
• Analyze 1 Frame Backward
: Analyze the current frame by moving back to the previous frame.
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