VRChat Worlds Skill

Version: 1.0 Stack: VRChat SDK, Unity

A VRChat world that runs at 30fps on your PC can run at 5fps on Quest. Realtime lights that look great in the editor tank performance for every player in the room. The Unity editor lies about performance — everything looks smooth until you test on actual hardware with actual players. And VRChat's performance ranking system means a poorly optimized world gets fewer visitors, not just a worse experience.

Quest-first building with baked lighting, proper spawn setup, and occlusion culling means your world runs well everywhere and gets promoted by the ranking system.

---

Scope and Boundaries

This skill covers:

• World setup and scene hierarchy
• VRChat performance limits
• Lighting and baking
• Spawn and respawn setup
• World optimization
• SDK components

Defers to other skills:

• vrc-udon: Scripting and networking
• unity-csharp: C# patterns and performance optimization

Use this skill when: Building or optimizing VRChat worlds.

---

Core Principles

1. Quest Compatibility — Build for Quest first, enhance for PC.
2. Bake Everything Possible — Realtime lighting kills performance.
3. Respect the Limits — Stay within performance ranks.
4. Test on Device — Editor performance lies.
5. Spawn Matters — First impression is at spawn.

---

Performance Limits

Quest (Target: Excellent/Good)

Metric	Excellent	Good	Medium
Triangles	50,000	100,000	200,000
Batches	50	100	200
Materials	25	50	75
Lights (realtime)	0	1	2

PC (Target: Excellent/Good)

Metric	Excellent	Good	Medium
Triangles	500,000	1,000,000	2,000,000
Batches	100	200	400
Materials	50	100	200
Lights (realtime)	2	4	8

---

Patterns

Scene Hierarchy

World
├── Environment
│   ├── Static (mark as static)
│   │   ├── Ground
│   │   ├── Buildings
│   │   └── Props
│   └── Dynamic
│       └── Interactive objects
├── Lighting
│   ├── Directional Light (baked or mixed)
│   ├── Light Probes
│   └── Reflection Probes
├── Audio
│   └── Audio sources
├── VRChat
│   ├── VRCWorld (descriptor)
│   ├── Spawn Points
│   └── Mirrors/Portals
└── Udon
    └── Scripts and behaviors

Spawn Area Setup

Spawn Checklist:
- Multiple spawn points (avoid stacking)
- Clear floor (no obstacles)
- Good lighting (players see themselves)
- Mirror nearby (avatar check)
- Safe area (no hazards)
- Interesting view (sets the mood)

Lighting Setup (Quest-Compatible)

1. Set all lights to "Baked"
2. Mark static geometry as "Contribute GI" + "Reflection Probe Static"
3. Place Light Probes for dynamic objects
4. Place Reflection Probes for shiny surfaces
5. Bake with GPU Lightmapper
6. Delete realtime lights or set to "Not Important"

Occlusion Culling Setup

1. Mark large static objects as "Occluder Static"
2. Mark all static objects as "Occludee Static"
3. Window > Rendering > Occlusion Culling
4. Set appropriate cell sizes
5. Bake
6. Test with Occlusion visualization

---

Anti-Patterns

Anti-Pattern	Problem	Fix
Realtime lights on Quest	Tanks performance	Bake all lighting
No light probes	Dynamic objects are black	Add light probe groups
Single spawn point	Players stack on join	Multiple spread spawns
Unbaked reflections	Expensive or broken	Use baked reflection probes
No LODs on props	Full detail at distance	Add LOD groups
Post-processing on Quest	Not supported, ignored	PC-only or remove

---

Checklist

Setup

• VRCWorld descriptor configured
• Multiple spawn points placed
• Respawn height set appropriately
• Reference camera configured

Performance

• All static objects marked static
• Lighting fully baked (Quest)
• Light probes cover play area
• Occlusion culling baked
• LODs on significant meshes
• Tested on Quest hardware

Quality

• Spawn area is welcoming
• Mirror available near spawn
• No z-fighting or visual glitches
• Audio levels balanced
• World descriptively named

---

References

• references/lighting-baking.md — Baked lighting setup for VRChat worlds

Assets

• assets/world-upload-checklist.md — Complete world upload checklist