An actor wears a suit covered in reflective markers. Cameras around the stage track the markers. A computer records the actor's movements. Those movements drive a digital character. That is motion capture, a technology that translates live performance into digital animation. It is used in films like Avatar, The Lord of the Rings, and Planet of the Apes. It is also used in video games, where it creates realistic character animation.

Motion capture has several forms. Optical motion capture uses cameras and reflective markers. Inertial motion capture uses sensors on the body. Facial motion capture uses cameras to record the actor's expressions, which are then mapped onto the digital character. Performance capture combines body and facial motion capture, allowing the actor to perform the entire character. Andy Serkis is the most famous performance capture actor, having played Gollum, Caesar, and King Kong. His performances are not just technical. They are creative. The technology captures the performance. The actor creates it.

Motion capture is not a replacement for animation. It is a tool. Animators still refine the performance, adjusting the timing, the poses, and the expressions. The best motion capture performances are a collaboration between the actor and the animator. The technology is improving. Real-time motion capture allows the director to see the digital character on set, interacting with the other actors. That makes the performance more natural and the direction more precise. Motion capture is changing how films are made.