One of the oldest animation techniques that is still in use
today is rotoscoping. When using this technique, animators trace over live
action film movement on each frame to use in an animated film. When it was
first used, live action film images were projected onto a glass panel that was
frosted where an animator would redraw them. The associated projector is called
a rotoscope. However, computers have replaced it in the past two decades.
Today, the term refers to manually creating a matte for a visual element on a
live action plate in order to composite it onto another background for use in
film or a movie.
How does Rotoscoping Work?
A rotoscope’s output
may slightly deviate from the original true line of the image that vary
between frames. When the frames are animated, an unnatural shake that is also
referred to as a “boil” may result. Sometimes animators purposely use this
effect. However, the effect is more commonly used to remove a single object
form a movie scene in order to use it on a different background. One of the
more famous examples is the light saber effects used in the first three Star
Wars movies that were created by rotoscoping real sticks that the actors held.
The biggest advance in the technique is using computers to construct the
animation of the frames that the engineer or animator traces.
