Rotoscoping

Rotoscoping is an animation technique that animators use to trace over motion picture footage, frame by frame, to produce realistic action. Originally, live-action movie images were projected onto a glass panel and traced onto paper. This projection equipment is referred to as a rotoscope, developed by Austrian-American animator Max Fleischer. This device was eventually replaced by computers, but the process is still called rotoscoping.

In the visual effects industry, Rotoscoping is the technique of manually creating a matte for an element on a live-action plate so it may be composited over another background. Chroma key is more often used for this, as it is faster and requires less work, but Rotoscoping provides a higher level of accuracy and is often used in conjunction with Chroma-keying. It may also be used if the subject is not in front of a green (or blue) screen, or for practical or economic reasons.