Follow through and overlapping action is a general heading for two closely related
animation techniques which form part of the
12 basic principles of animation identified by
Disney
The Walt Disney Company, commonly known as Disney (), is an American multinational mass media and entertainment conglomerate headquartered at the Walt Disney Studios complex in Burbank, California. Disney was originally founded on October ...
animators
Frank Thomas and
Ollie Johnston
Oliver Martin Johnston Jr. (October 31, 1912 – April 14, 2008) was an American motion picture animator. He was one of Disney's Nine Old Men, and the last surviving at the time of his death from natural causes. He was recognized by The Wa ...
in their authoritative 1981 book on Disney animation, ''
The Illusion of Life''. The term ''drag'' is sometimes included to form three separate but related concepts in the art of animation.
Definition
Follow through and overlapping action are closely related techniques which, when applied to animation, can help to render movement more realistically by more closely obeying the
laws of physics
Scientific laws or laws of science are statements, based on repeated experiments or observations, that describe or predict a range of natural phenomena. The term ''law'' has diverse usage in many cases (approximate, accurate, broad, or narrow) a ...
. At the Disney Studio, Walt Disney was eager to push his animators to improve their work and develop their skills. He told them:
:"Things don't come to a stop all at once guys; first there's one part and then another"
[Thomas and Johnston, p.59]
The animators, keen to make their work feel more convincing, developed the concepts of "Follow Through" and "Overlapping Action", though the concepts were so closely related that they were not always easy to distinguish.
Thomas and Johnston identified five areas of motion where these principles would apply:
1. A character might have a coat or long ears, and these parts would keep moving once the figure had stopped moving. The ears, or coat, would "follow through" even after the main action had stopped.
2. Bodies in motion do not move all at once, rather different parts of a body may move at different speeds. Therefore, as one part of the body stops, another part (such as an arm), might overlap or follow throu