An offset origin track has fixed assigned world coordinates that, for a given coordinate system, uniquely determine its image position at each step in a video clip. When an offset origin is dragged in the main video view, the origin of the coordinate system moves with it in order to maintain the offset origin's assigned world coordinates. This makes it useful for remotely setting the position of the origin, particularly when the origin is outside the video image.

1. Marking an offset origin

After creating an offset origin, click on a feature in the video image that has known world coordinates. Marking a single frame is all that's required. The offset origin is initially assigned the current world coordinates of the clicked image feature. The x- and y-components of the world coordinates are displayed on the toolbar when the offset origin is selected.

2. Changing the world coordinates (moves the origin)

Select the offset origin and enter the desired values in the x and y fields on the toolbar to change its world coordinates.

Note: changing the world coordinates of an offset origin moves the coordinate system origin so that the offset origin's image position remains unchanged.

3. Moving the offset origin (moves the origin)

Select and drag or nudge the offset origin to a desired location in the main video view.

Note: moving an offset origin moves the actual coordinate system origin with it so that the offset origin's world coordinates remain unchanged.

4. Locking the offset origin

Locking the offset origin prevents it from making any changes to the origin. Lock the offset origin by turning on the Locked property in its track menu.