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name: building-router description: Router for 3D building game mechanics in Three.js. Use when creating survival games, sandbox builders, base builders, or any game with player-constructed structures. Routes to 9 specialized skills for performance, physics, multiplayer, terrain, decay, UX, platform support, and design reference. Start here for building mechanics projects.

Building Mechanics Router

Routes to 9 specialized skills based on game requirements.

Routing Protocol

1. Classify — Single/multiplayer + scale + core features
2. Match — Apply signal matching rules below
3. Combine — Most games need 3-5 skills together
4. Load — Read matched SKILL.md files before implementation

Quick Route

Tier 1: Core Mechanics

Need	Skill	Signals
Spatial queries, collision	performance-at-scale	slow, lag, optimize, spatial, collision, thousands
Stability, damage, collapse	structural-physics	stability, collapse, support, damage, Fortnite, Rust, Valheim
Network sync, prediction	multiplayer-building	network, multiplayer, sync, server, latency, authoritative

Tier 2: Enhanced Features

Need	Skill	Signals
Slopes, foundations, anchoring	terrain-integration	slope, terrain, foundation, ground, pillar, heightmap
Timer decay, Tool Cupboard	decay-upkeep	decay, upkeep, maintenance, tool cupboard, abandoned
Blueprints, undo/redo, preview	builder-ux	blueprint, prefab, undo, redo, ghost, preview, selection

Tier 3: Platform & Reference

Need	Skill	Signals
Touch, VR, accessibility	platform-building	mobile, touch, VR, hand tracking, colorblind
Design analysis, trade-offs	case-studies-reference	how does Fortnite/Rust do, compare games, trade-offs

Signal Priority

When multiple signals present:

1. Multiplayer explicit → multiplayer-building required
2. Scale indicator → >1000 pieces triggers performance-at-scale
3. Persistence → Long-running servers trigger decay-upkeep
4. Platform constraint → Mobile/VR triggers platform-building
5. Default → structural-physics always relevant for building games

Common Combinations

Full Survival (Rust-style, 6 skills)

performance-at-scale → spatial indexing
structural-physics → stability + damage
multiplayer-building → networking
terrain-integration → foundations on slopes
decay-upkeep → Tool Cupboard + upkeep
builder-ux → blueprints + undo

Battle Royale Building (2 skills)

performance-at-scale → fast collision
multiplayer-building → low-latency sync

Single-Player Builder (3-4 skills)

structural-physics → stability + damage
terrain-integration → natural terrain
builder-ux → blueprints + undo
performance-at-scale → if >1000 pieces

Persistent Server (4 skills)

multiplayer-building → networking
structural-physics → stability
decay-upkeep → automatic cleanup
performance-at-scale → entity management

Decision Table

Mode	Scale	Terrain	Skills
Single	<1K	Grid	physics + ux
Single	<1K	Natural	physics + terrain + ux
Single	>1K	Any	performance + physics + ux
Multi	Fast	Any	performance + multiplayer
Multi	Survival	Any	performance + physics + multiplayer + decay
Multi	Persistent	Any	performance + physics + multiplayer + decay + ux

Integration Order

When combining skills, wire in this sequence:

1. Spatial index → Query foundation for all other systems
2. Validator → Uses spatial for neighbor/support detection
3. Damage → Uses spatial for cascade radius
4. Network → Broadcasts all state changes
5. Client prediction → Uses local spatial + validator

Fallback

• No scale stated → Ask: "How many pieces expected?"
• Unclear mode → Ask: "Single-player or multiplayer?"
• Generic "building game" → Start with structural-physics + builder-ux

Reference

See references/integration-guide.md for complete wiring patterns and code examples.