Rotoscope

A rotoscope is a device that enables animators to trace the movement of live actors, frame by frame, into an animation sequence. The rotoscope is decried by some animation purists, but has often been used to good effect. The device was invented by Max Fleischer, who used it in his series "Out of the Inkwell" starting around 1914. Ralph Bakshi is a particularly notorious director who favoured this animation method, and was criticized as overusing it.

The rotoscope has also been used as a tool for special effects in live action movies. By tracing an object, a silhouette (called a matte) can be created that can be used to create an empty space in a background scene. This allows the object to be placed in the scene. Such a technique, of creating mattes by hand, was used in the movie . Because of this special-effects usage, in computer graphics, to rotoscope is to create an animated matte indicating the shape of an object or actor at each frame of a sequence, as would be used to composite a CGI element into the background of a live action shot.