# Animation

## Principle

Motion gives the illustrated world breath. It must deepen atmosphere, state and meaning without turning the Scene into a cartoon.

## Motion bands

| Band | Examples | Typical period | Amplitude |
|---|---|---:|---:|
| Ambient slow | haze, distant cloud, canopy breath | 8–30 s | 1–4 px at 1× |
| Ambient living | leaves, banners, water, distant birds | 3–12 s | 2–10 px |
| Local continuous | flame, fireflies, bees, portal shimmer | 0.8–6 s | asset-specific |
| Attention response | focus light, sigil resolve | 140–260 ms | restrained |
| Activation | Portal open, Object transformation | 240–900 ms | scene-responsive |
| State settle | changed, completed, connected | 360–1200 ms | dispersing |

## Easing

- environmental: sinusoidal with phase variation;
- focus: cubic out;
- activation: quintic in/out or critically damped spring;
- light: smoothstep; never linear flicker;
- appearance: opacity plus 1–2% scale only when spatially appropriate.

## Phase and repetition

Adjacent vegetation, portrait standards, lanterns and fauna must not share phase. Use deterministic Scene seeds so motion remains stable across sessions while avoiding synchronized loops.

## Animation metadata

Each animation declares ID, trigger, duration, loop, amplitude, affected channels, interruption policy and reduced-motion behavior. Runtime state is authoritative; an animation never silently changes Permission, lifecycle or Activity state.

## Reduced motion

Replace movement with stable material, luminance or sigil changes. Preserve timing necessary for comprehension, but remove parallax sweeps, repeated pulses, camera drift and large spatial translation.

## Performance

Budget ambient motion by Area and Attention. Offscreen Components pause. Distant motion can be composited. Never sacrifice focus response, input latency or accessible state feedback to preserve ambient animation.