In the 3D window, select the part whose track you plan to modify.
The edit track mode is activated, the film representing the track is highlighted, the part is highlighted in green, the 3D is synchronized at the end of the operation implementing the part, and the part is positioned at the end of the track.
Insert a new shot at the end of the track using the Robot.
Insert another shot after the current one.
Exit the edit mode by double-clicking in empty space of the window (or select another part) .
The 3D data is restored to its initial state.
Use the Play button in the Compass to simulate the new track.