Free 3D training: Disney’s 12 classic principles of animation

Master Disney’s 12 classic principles of animation in 3D with Steve Lambert’s regular series of articles on the fundamentals of CG. This week: squash and stretch

In this series, Weta Workshop’s animation director Steve Lambert will guide you through the 12 classic priniciples of Disney animation – starting this week with the concepts behind squash and stretch.

FOR: Any software | TIME TAKEN: 10 minutes | TOPICS COVERED: Squash and stretch |ALSO REQUIRED: Maya (to view scene files)

Download the project and animation files for this training: fundamentals.zip (12.3MB)

Back in 1981, Frank Thomas and Ollie Johnston – two of Disney’s ‘Nine Old Men’ – published The Illusion of Life: a landmark book that set out in print the 12 principles of animation that have guided the company’s animators since the 1930s. Over the next 12 weeks, I’m going to show you how to apply these classic animation principles to your 3D work.

It’s important to note that none of the principles stand in isolation from each other. All combine to create a successful animation – but just like a toolbox, not every job requires every tool. Bear in mind that I will also hesitate to refer to anything as ‘wrong’ or ‘incorrect’. They’re principles, not rules!

Here, we’ll cover the first principle: squash and stretch. The caramel-covered marshmallow of the animation chocolate box, squash and stretch is the animator’s attempt to mimic the way objects deform in motion.

It is about so much more than the bouncing balls often used to demonstrate it: it can be used to convey weight, accentuate movement and enhance a character’s flexibility. It isn’t just for cartoony animation, either.

Adding squash and stretch to Andy and the ball really makes the animation come alive. This still doesn't show it off, so make sure you download the zip doc to watch the animation in action

One thing to bear in mind when squash-and-stretching is the need to maintain a constant volume. When you animate an arm stretching, the thickness of the limb should decrease.

Think of a rubber band: if you pull the ends, the rubber is distributed along a greater distance, so the band thins out. The same is true if you’re squashing an object: the mass has to go somewhere, and it generally bulges outward – keeping the volume, if not the shape, constant.

Squashing and stretching Andy

To illustrate this, I’ve put together a few example animations, which you can find in the Animation folder of the Fundamentals download. (If you’re using Maya, you can also explore the corresponding scene files.)

The Andy01 clip shows Andy, our character for the next 12 issues, running from a billiard ball with no squash and stretch.

In Andy02, I’ve applied squash and stretch to both Andy and the ball. You can see how the stretching of Andy’s body as he falls and the compression as he hits the ground add a bit of punch to the animation, emphasising his weight and movement.

In this example, however, the ball no longer seems right. The squishiness kills the impression that it is a hard, rigid object. Replace the texture to make the ball a basketball, though (see Andy03), and the result is much more believable.

Facial animation

The second example is of a basic facial animation take.

Take01 has no squash and stretch.

In Take02, I’ve distorted the features to elongate the expression. This drags the face along the path of movement and enhances the motion. Take03 goes one step further, changing the shape of the entire head as it moves. I’ve intentionally made the result over the top, but this sort of thing can be done more subtly to great effect.

That’s it for this week. Next time, we’ll look at principle two: anticipation. Bet you can’t wait…