# Motion & Animation Foundation v1.0

Status: Accepted for Sprint 1.4  
Scope: heroes, enemies, bosses, props, UI, particles, and VFX.

This foundation defines all movement rules for Streetline Heroes. Animation must feel responsive, readable, weighty, and arcade-sharp before it feels smooth.

## Core Philosophy

| Principle | Rule |
| --- | --- |
| Gameplay First | Movement must communicate game state and input intent. |
| Readability First | Key poses must read at combat scale. |
| Weight over Smoothness | Fewer strong frames beat many mushy frames. |
| Snappy Controls | Player actions need quick response and clear recovery. |
| Arcade Feel | Impact, contrast, pose holds, and timing exaggeration are expected. |

## Modules

1. [Animation Philosophy](animation/01_AnimationPhilosophy.md)
2. [Timing](animation/02_Timing.md)
3. [Spacing](animation/03_Spacing.md)
4. [Weight](animation/04_Weight.md)
5. [Anticipation](animation/05_Anticipation.md)
6. [Follow Through](animation/06_FollowThrough.md)
7. [Arcs](animation/07_Arcs.md)
8. [Smear Frames](animation/08_SmearFrames.md)
9. [Impact Frames](animation/09_ImpactFrames.md)
10. [Animation Readability](animation/10_AnimationReadability.md)
11. [Frame Planning](animation/11_FramePlanning.md)
12. [Animation QA](animation/12_AnimationQA.md)

## Frame Counts

| Animation | Standard frames | Notes |
| --- | ---: | --- |
| Idle | 4-8 | Subtle breathing and weight shifts. |
| Walk | 8 | Full readable contact cycle. |
| Run | 8 | Stronger spacing and diagonal lean. |
| Jump | 6 | Anticipation, takeoff, air, peak. |
| Fall | 4 | Clear downward read. |
| Attack Light | 5 | Fast anticipation, impact, recovery. |
| Attack Heavy | 7 | Larger anticipation and hit hold. |
| Block | 3 | Snap into protected silhouette. |
| Hit | 3 | Fast reaction, readable direction. |
| Death | 8 | Collapse and settle. |
| Taunt | 8 | Personality pose. |
| Victory | 8 | Readable celebration loop. |

## Motion Types

| Type | Motion rule |
| --- | --- |
| Heroes | Responsive, readable, expressive. |
| Enemies | Faster, cheaper, lower detail, clear threat telegraph. |
| Bosses | Slower, heavier, larger anticipation, longer impact holds. |
| Props | Simple state animation, clear break/hit/move state. |
| UI | Snappy, minimal, no distracting bounce. |
| Particles | Short-lived, directional, clustered. |
| VFX | Cause and result readable in the first frames. |

## QA Checklist

```text
□ timing
□ spacing
□ weight
□ arcs
□ anticipation
□ follow through
□ readability
□ events
□ schema
```

Machine-readable events live in `assets/definitions/animation/events.standard.yaml`.