Performance capture

Performance capture is a term possibly coined by the creators of The Polar Express movie. It is a combination of motion capture and facial expression capture, using the actions of live actors as input to digital image generators to create more naturalistic animation.

In performance capture, actors wear the same reflective markers as in motion capture, but also special makeup to record the facial movements. The actor usually interacts with wireframe models of the objects in the scene. The recorded performance data can be used to animate different actors. In The Polar Express Tom Hanks played five roles - an 8-year old boy, his father, the train's conductor, a hobo, and Santa Claus.

Although the technique has been used in some earlier films and computer games, The Polar Express was the first movie made solely with the process. This film was directed by Robert Zemeckis, who had a long history of technical innovations in filmmaking (historical composites in Forrest Gump and the combination of animation and live action in Who Framed Roger Rabbit) and became a self-professed fan of performance capture (he produced the 2005 thriller Monster House made using the same technique) because of the creative freedom it gives the director. Zemeckis is currently using performance capture in an adaptation of Beowulf scheduled for 2007 release.

Most recently, Titanic director James Cameron has been given permission to lease the performance capture technology to bring to life the numerous monsters and cyborg characters in his next theatrical motion picture Battle Angel Alita. Cameron explains that the film's main star, Alita, a young cyborg girl, will be completely computer generated, using performance capture.