The 12 Principles of Animation, Applied to AI Character Animation

What are the 12 principles of animation?

The twelve principles are a working vocabulary for why some movement feels alive and some feels like a cut-out slid across a table. Frank Thomas and Ollie Johnston, two of the Disney animators known as the “Nine Old Men”, set them down in their 1981 book Disney Animation: The Illusion of Life (Abbeville Press); the 1995 Hyperion edition reversed the title to The Illusion of Life: Disney Animation, which is how most people cite it now. The book records practice rather than theory: methods the studio’s animators had worked out from the 1930s onward.

In 1987 John Lasseter’s SIGGRAPH paper, Principles of Traditional Animation Applied to 3D Computer Animation, explained how the same ideas carry over to 3D computer animation. AI video is simply the newest medium they apply to. The twelve, under their usual names:

1. Squash and stretch
2. Anticipation
3. Staging
4. Straight ahead action and pose to pose
5. Follow through and overlapping action
6. Slow in and slow out (often taught as ease in and ease out)
7. Arcs
8. Secondary action
9. Timing (often paired with spacing in modern courses)
10. Exaggeration
11. Solid drawing
12. Appeal

Most explainers stop at definitions and a bouncing ball. This guide is about a newer job: getting a short AI-generated character loop to show these qualities when you never touch a frame.

What changes when an AI draws the frames

A traditional animator builds each principle in by hand. With an AI character tool you have three levers instead, and every principle is reached through one of them:

• Language. A motion prompt describes a performance. Words like “springy”, “winds up” or “settles” are requests the model may not always honour, but they shift the odds a long way.
• Selection. The same prompt produces different takes. You act like a director at a casting session: generate, judge against the principles, keep or regenerate.
• Editing. Some faults are timing or framing problems, and an editor fixes those without a new generation.

The second prompt is still one action, but it asks for anticipation, squash and stretch, follow through and a clean ending. That is the method in miniature.

In Character Animation AI the levers sit at different stages of a two-step flow. Solid drawing and appeal are mostly settled when the design is drawn and approved, and motion cannot rescue a weak design. Staging is shaped by the format: a square 720×720 frame with a fixed camera. Everything else lives in the Custom motion prompt and the free editor, which offers trim (down to 0.5 seconds), speed from 0.5× to 2×, forward, reverse or back-and-forth playback, mirror, and zoom and reframe without spending credits. Clips render at 24 fps in lengths of 4 to 12 seconds. The structure of a good Custom prompt is in the motion-prompt section of the image guide; the principles below are the words you pour into it.

Squash and stretch, anticipation and staging (principles 1–3)

1. Squash and stretch

Soft things change shape under force: a body flattens as it lands and lengthens as it springs up, while its volume stays the same. The amount of deformation tells the viewer what the character is made of. In a loop, it is the difference between a bounce that lands and a sticker moved up and down.

• Prompt: “lands with a soft, springy squash, then stretches tall as it bounces up”. For a rigid character, put it in the soft parts: “its antenna bends and wobbles on each landing”.
• Check: after each squash, does the character return to exactly its own proportions? A head that grows, or a body that stays wider, is a volume failure.
• Editor: nothing adds it. Round, soft designs show it most readily; ask a lanky or rigid one for less.

2. Anticipation

Before a big action comes a small opposite one: the crouch before a jump, the arm drawn back before a throw. It prepares the audience so the action reads instead of startling. Without it, the character looks yanked by a string.

• Prompt: give the preparation its own beat: “bends its knees and dips down, then springs up”, or “draws its paw back, pauses, then waves”.
• Check: is there a visible wind-up in the opposite direction? A jump from straight legs is missing it.
• Editor: when trimming the start, keep the wind-up, which may be only a few frames (a third of a second is eight frames at 24 fps). Loop it forward, not back-and-forth: anticipation played in reverse stops reading as preparation.

3. Staging

Staging presents one idea so clearly that nobody can miss it. With one square frame, a fixed camera and a transparent background, that comes down to a readable silhouette, a character that stays in frame, and a clip that faces the right way on the page.

• Prompt: keep the action on the spot (“turns to face the viewer and waves”, not “walks across the frame”) and prefer poses that read in outline: “raises the trophy high above its head” reads; “hugs the trophy” may not.
• Check: squint, or view it tiny. Can you name the action from the silhouette? Does an ear or tail leave the frame?
• Editor: mirror, so the character faces into your content rather than off the screen; zoom and reframe to tighten a small figure; an output size (720, 480, 360 or 240) matching where it will be shown.

Pose to pose, follow through and slow in and slow out (principles 4–6)

4. Straight ahead action and pose to pose

Two ways of working: straight ahead draws frame after frame for loose, spontaneous motion; pose to pose sets the key poses first for control and clarity. You cannot place keyframes in an AI generation, but you can name them. A prompt stating the start, key and end poses is pose to pose in words; one that only names an activity (“dances happily”) hands over the choreography, closer to straight ahead: livelier, less predictable.

• Prompt: “starts standing relaxed, throws both arms up in a big V, holds it for a beat, then returns to standing”.
• Check: pause on the strongest moment. Is there a clear, held key pose, or does the motion pass through mush?
• Editor: trim to the best poses. A 6-second take with one excellent 3-second section is a 3-second clip, not a reject.

5. Follow through and overlapping action

Parts of a body do not stop together. When a character halts, its ears, tail, hair or scarf keep travelling and settle a moment later, and different parts move on slightly different schedules throughout. It is the strongest cue that a character is not one rigid piece, and its absence is the usual reason AI motion looks stiff.

• Prompt: describe the lag: “stops suddenly; its long ears keep swinging and settle a moment later”. This needs something loose in the design; a character with no ears, tail or clothing has little to overlap.
• Check: when the body stops, does anything keep going? If everything freezes on the same frame, it is missing.
• Editor: trim the start, not the end. The settle usually happens in the last second.

6. Slow in and slow out

Movement accelerates out of one pose and decelerates into the next; constant speed looks mechanical. Generated motion is often fine mid-clip and fails at the edges, with a take still moving on its final frame.

• Prompt: “eases slowly into the pose”, and for loops, “comes to rest and holds still for the final second”.
• Check: does the last half-second settle into stillness, or cut off mid-move?
• Editor: back-and-forth playback. At the turnaround, the end of the motion becomes the start of the return trip: if it eases to a stop the reversal is invisible, and if it is still moving it shows as a hard snap. Trimming to the eased section rescues an abrupt ending.

Arcs, secondary action and timing (principles 7–9)

7. Arcs

Living things move along curves: a head turns with a slight dip, a waving arm pivots from the shoulder. Straight-line paths read as mechanical.

• Prompt: “swings its arm in a wide, sweeping arc”, “its head dips slightly as it turns to look”.
• Check: follow one point (the nose, a fingertip). Does it trace a curve, or ride a straight rail with sudden corners?
• Editor: none. A broken arc means a new take.

8. Secondary action

A smaller action that supports the main one and adds personality: a blink during a wave, a tail flick while thinking. It supports and never competes; two actions of equal weight look busy.

• Prompt: attach it with “while”: “waves with one paw while tilting its head and blinking”. One secondary action is plenty at this length.
• Check: does your eye land on the main action first? If you watch the tail instead of the wave, it is too big.
• Editor: nothing adds it; trim off a stray gesture at either end.

9. Timing

How long an action takes decides both physics (heavy things move slower) and mood (slow reads as sleepy, quick as excited). At 24 fps a brisk nod might fill 12 frames, a lazy stretch three seconds. Timing is also the relationship between beats: a quick move after a held pause hits harder than the same move at an even pace.

• Prompt: name tempo and contrast: “a long, slow yawn, then a quick shake of the head”. Match clip length to the idea: one gesture fits 4 to 6 seconds; a single wave stretched over 12 invites padding.
• Check: does the tempo match the feeling? Is there at least one change of pace?
• Editor: speed, 0.5× to 2×. It changes the whole clip evenly, so it fixes tempo (a sluggish wave may look right at 1.25×) but not rhythm: it cannot lengthen the pause and quicken the jump. Rhythm needs a new prompt.

Exaggeration, solid drawing and appeal (principles 10–12)

10. Exaggeration

Pushing a pose or expression beyond realism so it reads more clearly. A small character on a phone screen needs more of it than an actor in a film: the viewer has fewer pixels and less time.

• Prompt: degree words: “a big, exaggerated cartoon double-take”, “slumps dramatically, shoulders dropping all the way”. Or turn it down: “subtle and understated” suits a calm brand.
• Check: does the emotion read in under a second at real size? Too much is also a fault: limbs stretching off-model, a face distorting into someone else.
• Editor: none; regenerate with stronger or softer words. Cartoon proportions take big poses more gracefully than realistic ones.

11. Solid drawing

For a hand animator, this means forms with volume, weight and balance, so a character does not flatten or wobble as it turns. You are not drawing, but the typical failures of AI motion are solid-drawing failures: a hand that gains a finger, a face that drifts during a turn, an arm that melts into the body.

• Where it lives: the design stage. A full-body, three-quarter-view design with simple shapes gives the motion a solid construction, and approval locks it for every later clip. The character design prompts guide covers what makes a design animatable.
• Prompt: avoid motions the design cannot support, such as fast spins or fiddly hand work. “Glances back over its shoulder” is safer than “spins around twice”.
• Check: step through frame by frame, watching hands, the face during turns, and limbs crossing the body.
• Editor: trim can remove a bad moment at either end; a broken middle cannot be saved.

12. Appeal

Appeal is not prettiness but the quality that makes people want to keep watching; a villain can have it. It comes from simple, readable shapes and motion that behaves like the same character every time.

• Where it lives: mostly the design (silhouette, proportions, one signature feature, the right style among Soft 3D, Stylized, Anime and Flat).
• Prompt: one feeling that fits the character: “a shy, hesitant little wave, eyes glancing down”, or “a confident, cheeky wink”. Two feelings in a short clip look like indecision.
• Check: watch it looping at real size, then ask someone who has not seen it to describe the character. If they name the personality you intended, it works.
• Editor: output size (720 Original, 480 Website, 360 Small, 240 Tiny), so you judge it as people will see it.

The 12 principles of animation at a glance

A reference for reviewing takes:

How to make AI animation look natural: judge, edit or regenerate

Natural-looking AI animation is mostly selection. Watch every take three ways before deciding anything:

1. Full size, normal speed, twice. What is the action and the feeling? Does anything float or freeze?
2. Frame by frame through contacts, turns and the final second. In QuickTime Player, pause the MP4 or MOV and use the Left and Right Arrow keys to step one frame (see Apple’s shortcut list).
3. At real size, looping, in place: on the page, in the slide, over the footage. Staging and appeal only show in context.

Then sort each fault into one of three piles:

• Edit (free, saved as a version): tempo slightly off (speed); dead time at either end (trim); a popping loop seam (back-and-forth, or trim); facing the wrong way (mirror); too small (zoom and reframe).
• Regenerate with a changed prompt (one credit): missing anticipation, follow through or secondary action; straight-line paths; wrong rhythm or feeling; an unreadable pose; leaving the frame; an invented prop.
• Back to the design: faults that appear in every motion, like a face that will not hold or a silhouette that vanishes when small. A new design means new animations, so be sure.

Change one thing per regeneration, or you will not know which words worked. And read the pattern: if two takes from the same prompt miss the same principle, rewrite that part of the prompt; if they miss different things, it is variation, so keep the closer take and finish it in the editor.

Some principles sit outside this format. There is no lip-sync, so a talking mouth’s squash and stretch is out of scope; no camera moves or cuts; no multi-character scenes. If you need frame-level control (an exact anticipation length, a hand-adjusted arc), a keyframe tool such as Blender, Toon Boom Harmony or Moho is the better choice; the comparison of AI character animation tools shows where each kind fits.

Try it: direct one clip using three principles

Do not chase all twelve at once. Pick the three that matter for the moment the clip serves:

• Idle or loading loop (easing, follow through, timing): “Breathes slowly and sways gently, ears drifting a moment behind the head, then settles still.” Export with back-and-forth playback.
• Success moment (anticipation, squash and stretch, exaggeration): “Crouches low, springs into a big joyful jump, lands with a soft squash, then stands still.”
• Greeting (staging, secondary action, appeal): “Turns to face the viewer and waves warmly while tilting its head, then lowers the paw and smiles.”

Generate one, run the three-pass check, and fix what the editor can before spending another credit. The app mascot guide’s motion-system section shows how to grow those clips into a reusable set.

A free account includes 3 credits once, no card: a design and two takes. For a commercial product, client work or ads, only the Professional plan includes a commercial licence; Free, Starter and Creator cover personal, educational and internal projects (see pricing). And if the craft has hooked you, Thomas and Johnston’s book is still the source, with Richard Williams’s The Animator’s Survival Kit (2001) as its practical companion.