Animation

Frame durations carry more of the life in a cycle than the drawings do. Uniform timing reads mechanical no matter how good the poses are.

Rules of thumb, at 60fps-equivalent thinking but expressed in milliseconds:

Cycle	Frames	Typical timing
Idle (breathing)	2–4	200–400ms each, slow
Walk	4–8	100–150ms; hold contact poses longer
Run	6–8	60–100ms
Attack	3–6	Fast on the strike (40–60ms), long on the hold (150–250ms)

Set a whole cycle at once: frame op set_duration with a durations array.

Draw the extremes, then the in-betweens. Never animate by nudging pixels frame to frame — drift accumulates and by frame six the character is a different size.

A walk cycle's canonical poses:

1. Contact — front foot lands, back foot pushing off. Widest stance.
2. Down — weight over the front leg, body at its lowest.
3. Pass — legs together, body at its highest. This is the frame people forget, and its absence is why a walk looks like sliding.
4. Up — pushing off, rising.

Then mirror all four for the other leg: 8 frames. A 4-frame walk uses contact and pass for each leg.

• Anticipation — a small movement opposite to the action before it. One frame of crouch before a jump. Skipping it makes everything feel weightless.
• Follow-through — hair, cloak and weapon keep moving after the body stops.
• Squash and stretch — sparingly, and only where a material would deform.
• Arcs — a hand travels along a curve, never a straight line.
• Overlap — parts do not all start and stop together.

Easing does not exist frame-by-frame; you get it from spacing. Poses close together = slow; far apart = fast. That is the whole trick.

1. rig the character onto separate layers first (see rules://06-layers-and-rigging).
2. Block in the key poses on their own frames. Look at them as a filmstrip.
3. Add in-betweens only once the keys read.
4. Set timing.
5. Tag the cycle. Untagged frames are unusable by a game engine.
6. Review with look op filmstrip — a vision model reads only the first frame of a GIF, so a filmstrip is the only way to actually see the motion.

• Does the character stay the same height? (Except deliberate squash.)
• Do limbs keep the same thickness?
• Does the light stay in the same place?
• Does the cycle loop — is frame N a plausible predecessor of frame 1?

look op onion composites a frame over its ghosted neighbours, for judging spacing and in-betweens without stepping through frames one at a time. cel ops tween and oscillate fill in in-between cels for secondary motion (a bob, a breath, a float) — but on small amplitudes their rounding to whole pixels can stutter, so hand-key the primary motion and save them for motion nobody is meant to consciously notice.