All animators follow the 12 principles of animation. Originally created for hand-drawn animation, it is now also applied to 3D animation.
1. Squash and Stretch
The idea here is that when an object (such as a ball) hits another, it should squash in, then stretch once more when in the air again. This conveys the movement of energy and the force of gravity on the object. This gives the object a sense of weight and flexibility, while still keeping its volume the same.
When performing an action, a normal human prepares for it. For example, when jumping the person would bend their legs first. We would animate our character the same way (using references) to make it appear much more realistic.
When animating, it’s important to give the character a clear and interesting silhouette. It’s also important to think about where they’re positioned in relation to the camera, objects or other characters. This is known as staging and is also used in theater. Good staging helps the viewer focus on important and relevant details.
4. Straight Ahead Action and Pose to Pose
Straight Ahead Action is the term used for animation drawn out frame by frame in sequence. Another method is Pose to Pose, where the important poses/key frames are drawn first, then the frames between are filled in. 3ds Max uses Pose to Pose animation, though Mass FX makes use of Straight Ahead animation after baking it.
5. Follow Through and Overlapping Animation
Follow Through is the mirror of Anticipation, in that it’s a movement after an action has been completed. For example, after a character turns their head, their hair would keep moving for a short while longer. Overlapping action is when different parts of the body move at different rates.
6. Slow In and Slow Out
Here, the idea is that when a character makes an action, they are at first slow, then quick, then slow when they finish. This can be reflected in animation by using more keyframes at the beginning and the end, but fewer in the middle.
Natural actions tend to follow an arced trajectory, so to achieve a realistic animation, we should incorporate this into our work. If an object moves out of its usual or expected arc, it appears erratic rather than fluid.
8. Secondary Action
A secondary action is an additional action that gives more life and character to the animation. For example, while walking, a character might put his hands in his pockets or swing them lightly. This does not detract from the original walking animation and instead enhances it.
Timing refers to the number of frames different actions take. For example, a run is faster than a walk, so would take less frames to complete a cycle.
Animations that are exactly like real life can end up looking static and dull, so movements or even features can be exaggerated to become more exciting or appealing.
A solid drawing is when a character is sketched out from multiple angles in order to give the animators an idea of how the character looks in a 3D sense, as opposed to a flat 2D image. This is obviously especially important for 3D animation and character modelling.
Appeal is what we would call charisma in a real life actor. You may animate a character beautifully and realistically, but if they lack charisma and character, they’ll end up flat in more than the literal sense. A flat character is boring and the audience can’t connect to them.