Applying the 12 Principles to 3D Animation
Tito A. Belgrave, Wednesday, 23 July 2003

From Isaac Kerlow's recent presentation at the 3D Festival in Copenhagen, and from the 3rd Edition of his book The Art of 3D Computer Animation and Effects, being premiered at SIGGRAPH 2003.

The twelve principles of animation were created in the early 1930s by animators at the Walt Disney Studios. These principles were used to guide production and creative discussions as well to train young animators better and faster. These twelve principles became one of the foundations of hand-drawn cartoon character animation. The twelve principles, as they are commonly referred to, also helped to transform animation from a novelty into an art form. By applying these principles to their work these pioneering animators produced many of the earliest animated feature films that became classics: Snow White (1937), Pinocchio and Fantasia (1940), Dumbo (1941), and Bambi (1942).

The twelve principles are mostly about five things: acting the performance, directing the performance, representing reality (through drawing, modeling, and rendering), interpreting real world physics, and editing a sequence of actions. The original principles are still relevant today because they help us to create more believable characters and situations. They can be applied to almost any type of animation, even though they work best for comedy. But, some of these principles require updates, and a few new additional principles are also needed to address the new techniques and styles of three-dimensional computer animation.

Animation techniques and styles, and the scope of productions, have changed tremendously since the 1930s. The dominant, almost exclusive, style of animation then was hand-drawn pose-to-pose cartoon narrative animation. Today we have more styles including non-linear interactive videogames and non-narrative music videos. In the 1930s some animation techniques and capabilities were underdeveloped, camera moves and lighting for example, or misunderstood: rotoscoping or stop-motion. Consider too the new tools that have transformed our craft: hand-held cameras, television, non-linear editing, compositing, motion capture, computer graphics and procedural tools. Other artforms have greatly evolved since the 1930s, creating new languages and new principles. It is time to do the same with animation, it is time to reinterpret and expand the original principles. We also need to create new additional principles that address today’s new animation styles and techniques. This is our collective challenge.

Squash and stretch, the first principle from the original twelve, is used to exaggerate the amount of non-rigid body deformations

usually with the purpose of achieving a more comedic effect. Three-dimensional squash and stretch can be implemented with a variety of techniques: skin and muscle, springs, direct mesh manipulation and morphing. It can also be implemented in more experimental ways with weighting, especially for dynamics simulations, and unusual IK systems.

The technique of anticipation helps to guide the audience’s eyes to where the action is about to occur. Anticipation, including motion holds, is great for “announcing the surprise.“ In three-dimensional computer animation it can be fine-tuned using digital time-editing tools such as time sheets, timelines, and curves. More anticipation equals less suspense. Horror films, for example, switch back and forth from lots of anticipation to total surprise.

Staging, or mise-en-scène as it is also known, is about translating the mood and intention of a scene into specific character positions and actions. Staging the key character poses in the scene helps to define the nature of the action. Three-dimensional animatics are a great tool for previsualizing and blocking out the staging before the primary, secondary and facial animation. There are many staging techniques to tell the story visually: hiding or revealing the center of interest, and a chain reaction of actions-reactions are a couple of them. Staging can also be aided with contemporary cinematic techniques such as slow motion, frozen time, motion loops, and hand-held camera moves.

Straight-ahead action and pose-to-pose are two different animation techniques that yield fairly different results. In the early days of hand-drawn animation pose-to-pose action became the standard animation technique because it breaks down structured motion into a series of clearly defined key poses. In straight-ahead action the character moves spontaneously through the action one step at a time until the action is finished. Motion capture and dynamics simulations, even three-dimensional rotoscoping, are clearly the straight-ahead techniques of three-dimensional computer animation. They can all be blended intelligently using channels.

Follow-through and overlapping action are two techniques that help make the action richer and fuller with detail and subtlety. Follow-through action consists of the reactions of the character after an action, and it usually lets audiences know how he or she feels about what has just happened or is about to happen. In overlapping action multiple motions influence, blend, and overlap the position of the character. In three-dimensional computer animation a lot of the common follow-through motions of clothing and hair, for example, can be animated with dynamics simulations. The layers and channels in three-dimensional computer animation software allow us to mix and blend different overlapping motions from different areas of the character.

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