# OpenSpec Change: enterprise-gaming-r3f-physics-cascade

- **Change ID**: enterprise-gaming-r3f-physics-cascade
- **Package**: `@suaveplan/r3f-physics-cascade`
- **Category**: gaming/physics
- **Target path**: `gaming/physics/r3f-physics-cascade`
- **Status**: PROPOSED
- **Date**: 2026-04-24

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## Summary

Deliver `@suaveplan/r3f-physics-cascade` on the genesis branch from scratch at enterprise quality. The package provides cascading physics effects for React Three Fiber: chain-reaction impulse propagation (impact → impulse list → rigid bodies receive forces), structural collapse simulation (rigid-body sleep/wake thresholds), and `CascadeZone` spatial boundaries that limit propagation extent. Wires to `@suaveplan/r3f-physics-rapier` via the core `PhysicsBackend` interface. Genesis adds structured errors, OTel cascade-event counter, and 100% coverage.

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## Available workspace deps

`@suaveplan/error`, `@suaveplan/types`, `@suaveplan/events`, `@suaveplan/r3f-physics-core`, react, `@react-three/fiber`, three.

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## Public API surface

```ts
function CascadeZone(props: CascadeZoneProps): JSX.Element
// center, radius, maxPropagations

function useCascade(): CascadeController
// trigger(origin, force, radius): void
```

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## File layout

```text
gaming/physics/r3f-physics-cascade/
  package.json / tsconfig.json / vitest.config.ts
  src/
    index.ts / error-codes.ts
    types/common.ts + md
    core/
      cascade-propagator/ (ts + md + types + test + index)
    context/cascade-provider.tsx + md + test
    hooks/use-cascade.ts + md + test
    components/
      CascadeZone/ (tsx + md + test + stories + index)
  tests/integration.test.ts
```