Capturing the motion of a target. One method includes: coupling a plurality of primary markers to the target; coupling at least one secondary marker to the target; capturing a plurality of primary marker data points, wherein each primary marker data point corresponds to one primary marker of the plurality of primary markers; capturing at least one secondary marker signature, each secondary marker signature corresponding to and uniquely identifying each secondary marker of said at least one secondary marker; and identifying the plurality of primary markers using said at least one secondary marker signature.