Motion capture or mocap is a technique of digitally recording movements for entertainment, sports, and medical applications.
Mocap started as a photogrametric analysis tool in biomechanics research in the 1970s and 1980s, and expanded into education, training, sports and computer animation for cinema and video games as the technology matured. A performer wears markers near each joint to identify the motion by the positions or angles between the markers. Acoustic, inertial, LED, magnetic or reflective markers, or combinations of any of these, are tracked, optimally at least two times the rate of the desired motion, to submillimeter positions. The motion capture computer software records the positions, angles, velocities, accelerations and impulses, enabling an accurate digital representation of the motion.

Mocap offers several advantages over traditional computer animation of a 3D model:

• More rapid, sometimes even real time results can be obtained.
• The amount of work does not vary with the complexity or length of the performance to the same degree when using traditional techniques.
• Complex movement and realistic physical interactions such as secondary animation, weight and exchange of forces can be more easily recreated in a physically accurate manner.
In addition to  film animation and training for complex tasks, other major application areas of motion capture are biomechanics and clinical medicine. Patients move freely within a defined area, and cameras track the range of motion, gait, and several other biometric factors, and this information is streamed live into analytical software.