Squash and stretch is the phrase used to describe "by far the most important" of the

12 basic principles of animation Disney's twelve basic principles of animation were introduced by the Disney animators Ollie Johnston and Frank Thomas (animator), Frank Thomas in their 1981 book ''The Illusion of Life: Disney Animation''. The principles are based on the work of ...

, described in the book ''

The Illusion of Life ''Disney Animation: The Illusion of Life'' (later republished as ''The Illusion of Life: Disney Animation'') is a book by Frank Thomas and Ollie Johnston, two of the key animators at Disney during the Golden age of American animation. Conten ...

'' by 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 Wal ...

Basis

The principle is based on observation that only stiff objects remain inert during motion, while objects that are not stiff, although retaining overall volume, tend to change shape in an extent that depends on

inertia Inertia is the idea that an object will continue its current motion until some force causes its speed or direction to change. The term is properly understood as shorthand for "the principle of inertia" as described by Newton in his first law ...

and elasticity of the different parts of the moving object. To illustrate the principle, a half-filled flour sack dropped on the floor, or stretched out by its corners, was shown to be retaining its overall volume as determined by the object's

Poisson's ratio In materials science and solid mechanics, Poisson's ratio \nu ( nu) is a measure of the Poisson effect, the deformation (expansion or contraction) of a material in directions perpendicular to the specific direction of loading. The value of Po ...

. Examples of the elasticity of the human body in motion were found in photographs the animators found in newspaper sports pages. Using these poses as reference the animators were able to start "observing (the motion) in a new way". Author Walt Stanchfield said, "A simple shape plus squash and stretch are all the anatomy you need for cartoon characters."

Application

The ball that would change shape, compressing ("squash") as it hit the ground, then extending (stretch) as it bounced up again, was the most simple example that was part of the preparatory training for Disney animators. During the 1930s, the squash and stretch were exaggerated by Disney animators, making it ever more extreme, but they had to maintain the overall volume of an object so that it did not appear to change volume as well as shape.

References

Animation techniques Animation terminology {{animation-stub

Basis

Application

See also

References