Squash and Stretch (S&S for short) is the principle of applying a contrasting change of shape—from a squash pose to a stretch pose or vice versa—to give a feeling of fleshiness, flexibility, and life in animation. The absence of squash and stretch gives a rigidity or stiffness to the motion. The transition between a proper Squash pose to a Stretch pose, or the other way around, breaks the perfect solidity that CG animation in particular inherently gives to everything.
Squash and Stretch In Action
Here the principle of S&S is boiled down to it’s essence on the classic Bouncing Ball. There is a Squash pose on the drawing where the ball is in contact with the ground, and Stretch poses just before and after it to provide the necessary contrast.
The classic bouncing ball with and without Squash and Stretch.Let’s look at it in motion. In the clip below, the S&S is not extreme, but see how even a subtle amount can make the difference by giving a touch of elasticity to the material. It no longer feels like a cardboard cutout or rock hard ball.
Bouncing Ball, No Squash and Stretch
Bouncing Ball, With Squash and Stretch
Side by Side Comparison
Squash and Stretch gives life and flexibility but not only that! It can help convey what the material that something is made of. In the bouncing ball case, very little S&S will indicate a firmer material, like a ping-pong ball or a bowling ball. A rubber ball, would naturally have more S&S. The application of S&S can be quite detailed when done with nuance and not just applied with a thick brush. More does not necessarily mean better.
Why do animators need Squash and Stretch?
Squash and Stretch can make characters and inanimate objects have a feeling of life by introducing a flexible quality. S&S can be applied to a single body part, say an eyeball, or the entire character’s pose. The latter is particularly useful when making rigid objects come to life, like the classic Disney Flour Sack, which is a beginning traditional animator’s test case.
