---
name: building-mechanics
description: Three.js 3D building system with spatial indexing, structural physics, and multiplayer networking. Use when creating survival games, sandbox builders, or any game with player-constructed structures. Covers performance optimization (spatial hash grids, octrees, chunk loading), structural validation (arcade/heuristic/realistic physics modes), and multiplayer sync (delta compression, client prediction, conflict resolution).
---

# 3D Building Mechanics

Complete building system for Three.js games with performance optimization, structural physics, and multiplayer networking.

## Quick Start

```javascript
import { SpatialHashGrid } from './scripts/spatial-hash-grid.js';
import { HeuristicValidator } from './scripts/heuristic-validator.js';

// Spatial indexing for fast queries
const spatialIndex = new SpatialHashGrid(10);
spatialIndex.insert(piece, piece.position);
const nearby = spatialIndex.queryRadius(position, 15);

// Structural validation (Rust/Valheim style)
const validator = new HeuristicValidator({ mode: 'heuristic' });
validator.addPiece(piece);
const canPlace = validator.validatePlacement(newPiece);
```

## Reference Files

Read these for detailed implementation guidance:

- `references/performance-at-scale.md` - Spatial partitioning, chunk loading, instancing, LOD
- `references/structural-physics-advanced.md` - Arcade vs heuristic vs realistic physics
- `references/multiplayer-networking.md` - Authority models, delta sync, conflict resolution

## Scripts

### Performance (references/performance-at-scale.md)
- `scripts/spatial-hash-grid.js` - O(1) queries for uniform distribution
- `scripts/octree.js` - Adaptive queries for clustered bases
- `scripts/chunk-manager.js` - World streaming for large maps
- `scripts/performance-profiler.js` - Benchmarking utilities

### Structural Physics (references/structural-physics-advanced.md)
- `scripts/heuristic-validator.js` - Fast validation (Fortnite/Rust/Valheim modes)
- `scripts/stability-optimizer.js` - Caching and batch updates
- `scripts/damage-propagation.js` - Damage states, cascading collapse
- `scripts/physics-engine-lite.js` - Optional realistic physics

### Multiplayer (references/multiplayer-networking.md)
- `scripts/delta-compression.js` - Only send changed state
- `scripts/client-prediction.js` - Optimistic placement with rollback
- `scripts/conflict-resolver.js` - Handle simultaneous builds
- `scripts/building-network-manager.js` - Complete server/client system

## Key Patterns

### Spatial Indexing Selection
| Pieces | Distribution | Use |
|--------|-------------|-----|
| <1,000 | Any | Array |
| 1-5k | Uniform | SpatialHashGrid |
| 1-5k | Clustered | Octree |
| 5k+ | Any | ChunkManager + Octree |

### Physics Mode Selection
- **Arcade** (Fortnite): Connectivity only, instant collapse, best for combat
- **Heuristic** (Rust/Valheim): Stability %, predictable, best for survival
- **Realistic**: Full stress/strain, expensive, best for engineering sims

### Multiplayer Pattern
Server-authoritative with client prediction. Use delta compression for sync.


---
Source attribution: Bbeierle12
Original project: https://github.com/Bbeierle12/Skill-MCP-Claude/blob/9f228393b17de9671959227d5fdaa43f147f0cb2/skills/3d-building-advanced/SKILL.md
License: MIT
License information: https://opensource.org/license/mit
Original upstream instructions; downloaded from Dave AI.

## Upstream license notice

MIT License

Copyright (c) 2025 Bbeierle12

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.



# Dave AI resource metadata

Creator / publisher: Bbeierle12
Original project: https://github.com/Bbeierle12/Skill-MCP-Claude/blob/9f228393b17de9671959227d5fdaa43f147f0cb2/skills/3d-building-advanced/SKILL.md
Attribution basis: Recovered original package and original project license at a pinned revision

Fields of work: Design, Development & Engineering
Roles: Frontend Developer, Game Developer, UX Designer
Specialties: Backend, Frontend
Tools: Three.Js
Country applicability: Country not specified
Classification basis: Source catalog labels
Instruction SHA-256: cc6b64873b3b5bae971ae791654071066337b409e9be723b82a8ccc340f36eac
Metadata reviewed: 2026-10-27
This metadata supersedes earlier Dave AI catalog attribution. Original instruction and supporting files are preserved.