Tracking Position

In this common case, you want the object to track only the changes in position of the reference feature. The object follows the X and Y motion without undergoing changes in scale or rotation.

For example, you have a clip of a woman wearing a pair of jeans with a label. You apply a Paint operator to the clip and draw a logo. You need to track the logo to one point on the label. Note in this example there are no scale or rotation changes to the label.

To track position:

1. Play the clip a few times to evaluate what reference feature you want to use and if there are any foreseeable problems for the tracking. See Finding a Good Reference Feature.
2. Determine a good reference frame. In this example, it is the first frame of the clip.
3. Position the object to be tracked at that frame. In this example, we position a Paint object (the logo) over the label on the back pocket of a pair of jeans.



4. Make sure the object is still selected, and click Position on the Tracker panel.

A Tracker appears in the center of the object and a Tracker folder appears in the Timeline.



5. Resize and/or reposition the reference and tracker boxes. In this example, the reference box is placed over the lower left corner of the label.



6. Make sure the Tracker is selected, and then adjust the settings on the Tracker panel. In this example, the following settings are used:
• Source is set to Background Clip because we do not need to take into account any objects or effects added to the clip.
• Mode is set to Relative because the logo must stay where it is and not snap to the center of the reference box when tracking starts.
• Axis is set to X & Y for the logo to follow both the horizontal and vertical motion of the label.
• Reference type is set to Fixed because the reference feature does not undergo any significant changes that would prevent a match from being found.
• Tolerance is left at its default value given that the reference feature should be easily matched throughout the clip.
7. Make sure the Tracker is selected and click the Analyze Forward button on the Tracker panel to start the analysis.

The Tracker follows the reference feature.

8. If a Trackers gets "lost", pause the analysis, make adjustments, and restart the analysis. See Advanced Tracking Techniques.
9. Save the Tracker data if necessary. Remember it has already been applied to the selected object (the logo). See Importing and Exporting Tracker Data.
10. Click the Off button in the Tracker panel when tracking is complete.