Motion 5 - Track Parameter Behavior Controls

The Track parameter behavior can be found in the Behaviors’ parameter subcategory in
the Library, or by choosing Parameter > Track from the Add Behavior pop-up menu in
the toolbar.

For a description of the Tracker Preview, Offset Track, Auto-Zoom, Auto-Zoom Mode,
Look Ahead Frames, and track list parameters, as well as tracker subparameters, see

Analyze Motion Controls

.

For information on using the Track parameter behavior, see

Track Parameter Workflow

.

Parameters in the Inspector

Source:

Drag the source object for the track to this well. The source object can be another

tracking behavior or a footage object. Drag a behavior to the Source well to load that
track into the Track parameter behavior. To clear a Source well, drag the item away from
the well and release the mouse button.

Note: An animated object cannot be used as a source for the Track parameter behavior.

• Action pop-up menu: Choose from a list of tracking data (from other tracking behaviors)

in the project.

Transform:

This pop-up menu allows you to choose how the selected position parameter

moves. There are two options:

• Attach to Source: This option anchors the position of the object to the recorded track

or animation source. Use Attach to Source when the source object is scaling or rotating,
and you want the filter’s center to stick to a specific spot on the source object. Any
animation that existed on the filter’s center before applying the track can be preserved
by using the Adjust parameters (Position, Scale, and Rotation), available when
Transformation is chosen from the Type pop-up menu.

Note: Although the object’s position is attached to the movement of the source object,
its position can be offset from the source object.

• Mimic Source: This option allows the object to mimic the recorded track or animation

source. Any animation that existed on the foreground object before applying the track
can be added to the track by selecting Position, Rotation, or Scale in the Adjust
parameters.

Note: As with Attach to Source, the object’s position can be offset from the source
object.

Movement:

Click the Analyze button to begin the motion tracking analysis. A status

window displays the tracking progress. To stop the analysis, click the Stop button in the
status window or press Esc.

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The start of the track is based on the current playhead position, rather than the start of
the behavior in the Timeline.

Reverse:

Click the Reverse checkbox to analyze the clip in reverse, 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:

Use this preview area to see 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:

If a tracker’s reference point becomes temporarily hidden or goes off the

screen, use this parameter 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 Using Offset Tracking

.

Auto-Zoom:

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, 2x,
4x, and 8x.

Auto-Zoom Mode:

Choose an option from this pop-up menu to set the display of the

auto-zoomed tracker in the Canvas. There are three choices:

• Normal: Displays a normal pattern.

• Contrast: Displays the tracker pattern with contrast detection.

• Edge: Displays the tracker pattern with edge detection.

The Auto-Zoom Mode applies to trackers in the Canvas and does not appear in the
Tracker Preview in the Behaviors Inspector.

Note: When None is chosen from the Auto-Zoom pop-up menu, the Auto-Zoom Mode
setting has no effect.

Look Ahead Frames:

Use this slider and value slider to specify the number of “future”

frames to be analyzed by the tracker. In other words, you can direct the tracker to look
in a specific location for its reference point. This is useful for footage that contains
fast-moving objects, because the reference point can quickly get away from the tracker.
For more information on using Look Ahead Frames, see

Giving Motion a Hint by Looking

Ahead

.

Track list:

Use this list to see the trackers in the behavior.

To disable a tracker, deselect its checkbox. A tracker that is turned off is not analyzed with
the track.

When another track is referenced, the track list is replaced with a Tracker pop-up menu.

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Click the disclosure triangle next to the track name to reveal additional parameters:

Position:

Displays the X and Y positions of the tracker. The X position is the value slider

on the left; the Y position is the value slider on the right. Click the disclosure triangle to
display labeled position value sliders.

Track Size:

Use this slider to adjust (in pixels) the pattern search size for the tracker. As

you adjust the track size, the Tracker Preview is updated to show the new track size (there
is no visual change in the Canvas tracker).

To adjust the Track Size without exposing its parameters, Option–drag left in the Tracker
Preview area to reduce the track size; Option–drag right to increase the track size.

Search Size:

Use this slider or value slider to increase or reduce the tracker’s search area

size. In Motion, you do not specify the size of a search area when setting up your trackers
in the Canvas. To change the default search size, use the slider or value slider. If Search
Size is set to 200 percent, the tracker’s search area is twice the default search area size.

Fail Tolerance:

Use this parameter to define the amount of tolerance for error, or

confidence value, of the track. In other words, this parameter defines at what score the
tracker determines it is able to match a reference feature. When above the score, the
tracker accepts the match. When below the score, the tracker rejects the match. When
the match is rejected, the Fail Behavior kicks in.

Fail Behavior:

Use this pop-up menu to specify 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: The analysis stops 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: The tracker uses manually added keyframes as a guide during

analysis. After you add keyframes, return to the start frame and start the tracking analysis.
If the tracker cannot locate the track pattern, the manually created tracking keyframes
are referenced to guide the tracker.

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Color:

Click or Control-click the color well to set a 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 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 apply parameter to 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 (via the Analyze button), to
reverse the direction of the track (via the Reverse checkbox), and to offset the track (via
the Offset Track checkbox).

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