This is a brief summary of the 12 basic principles of animation presented in The Illusion of Life: Disney Animation by Frank Thomas and Ollie Johnston.
They apply not only to cel and computer animation for noninteractive motion pictures but also in animation for video games.
Animation following these principles is part of why the characters in Aladdin and Pinocchio for Super NES have more life than the often stiffly animated characters of many 2D indie games from the 2010s.
- Squash
- Things contract when contacting a surface and stretch back on the rebound.
- Anticipation
- Show the wind-up for each move. This needs to be slightly compromised for jumps or quick attacks in a game in order not to look laggy.
- Staging
- Use the camera and lighting to draw attention to things.
- Pose to pose
- Draw key frames and make sure in-between frames fit between them.
- Follow through
- After contacting a surface, parts of an object farther from the point of contact will lag somewhat and continue to move for a short time. This especially includes hair and clothes.
- Ease in and ease out
- Things and parts of things don't immediately start or stop moving; they have momentum.
- Arc
- Things move in parabolas, not straight lines, with the degree of curvature dependent on the object's speed. For an object as a whole, this is usually taken care of by the physics engine.
- Secondary action
- This includes things like the arms of a walking or running bipedal character or the face of a character doing something else. If the secondary motion of a body part emphasizes the main action, emphasize it. Otherwise, downplay it during the primary action but don't completely eliminate it, and move most of it before or after the primary action.
- Timing
- Understand how quickly each object moves or squashes in response to a given stimulus. This depends on its mass and other physical properties.
- Exaggeration
- Make features and motions slightly more pronounced than in reality.
- Solid drawing
- Know the three-dimensional physical forms that you're projecting to two dimensions, and understand where the light and mass are. Don't make a character look so symmetric it's artificial.
- Appeal
- Make sure the viewer can read a character's expressive surfaces.