unity-vrc-world-sdk-3（Unity VRC world SDK 3 命令行）

VRChat World SDK 3 Guide

Table of Contents

Common Mistakes (NEVER List)

These cause silent world failures, performance disasters, or Quest incompatibility:

Reference Loading Guide

Load only what the task requires.

Before Starting a New World — Design Decisions

These decisions shape every downstream choice. Make them first, before placing any component.

The most expensive mistake: Designing for PC and adding Quest "later." By that point, lighting resolution, material complexity, and mesh density are locked. The Quest port then requires rebuilding the entire lighting and material pipeline.

Design Philosophy: Quest First

Build for Quest and get PC for free. Build for PC and Quest becomes a separate project.

Quest (Meta Quest 2/3/Pro) defines the performance budget:

• CPU/GPU: ~2× slower than PC VR; tile-based GPU with no hardware shadow maps
• VRAM: ~4 GB shared with OS (vs 6–12 GB on PC); no HDR framebuffer
• Thermal throttling: Sustained 100% GPU load causes clock reduction within minutes

If a world runs at 72 FPS on Quest with a single test client, it will typically run at 90+ FPS on PC — though results vary by shader complexity, CPU-bound workloads, and hardware differences. The converse rarely holds. Verify against the official VRChat optimization documentation before publishing.

NEVER optimize exclusively for PC with "Quest support added later" — by that point, lighting, materials, and mesh density are all locked to PC quality, and the Quest port requires rebuilding everything.

SDK Versions

Supported versions: SDK 3.7.1 - 3.10.3

Important: SDK versions below 3.9.0 are deprecated as of December 2, 2025. New world uploads are no longer possible with these versions.

Scene Setup

VRC_SceneDescriptor (Required)

Exactly one is required in every VRChat world.

[VRCWorld Prefab]
├── VRC_SceneDescriptor (Required)
├── VRC_PipelineManager (Auto-added)
├── VRCWorldSettings (Optional - movement speed settings)
└── AvatarScalingSettings (Optional - avatar scale limits)

All Properties

Reference Camera Usage

// Usage:
// 1. Adjust Near/Far clipping (recommended for VR: 0.01 ~ 1000)
// 2. Apply Post Processing effects
// 3. Set background color

// ⚠️ MUST disable the Camera component after configuring — an active Reference Camera
//    renders a second viewport. VRChat reads only the camera settings, not its output.
// Assign the configured (disabled) Camera to VRC_SceneDescriptor > Reference Camera.

Spawn Points Setup

// Spawn points are empty GameObjects assigned to VRC_SceneDescriptor > Spawns array.
// Players enter facing the Z+ direction of the spawn Transform.

// VRChat-specific requirements:
// - At least 2-3 spawn points (for simultaneous joins — single spawn causes overlap)
// - Place slightly above the floor (~0.1m) to avoid floor collision on spawn
// - Keep clear of obstacles (VR player guardian area is larger than their avatar)
// - Account for VR guardian boundaries — desktop player sizes differ from VR

Required Setup Checklist

□ Exactly one VRCWorld Prefab exists in the scene
□ At least one Transform set in Spawns
□ Respawn Height set to an appropriate value (well below the floor)
□ Reference Camera configured for clipping distances (for VR)
□ Layer/Collision Matrix correctly configured
□ "Setup Layers for VRChat" has been executed

Components

MANDATORY READ references/components.md (~800 lines) before configuring any VRC component below. Load in full — dependency requirements and Udon event hooks are distributed throughout. Do NOT Load: references/audio-video.md, references/lighting.md.

VRC_ObjectSync vs UdonSynced

SDK 3.8.0+: Force Kinematic On Remote — Makes Rigidbody kinematic on non-owner clients, preventing unexpected physics behavior.

Layers & Collision

VRChat Reserved Layers

Layer Setup Steps

1. VRChat SDK > Show Control Panel
2. Builder tab
3. Click "Setup Layers for VRChat"
4. Collision Matrix is automatically configured

MANDATORY READ references/layers.md when setting up collision or debugging physics. The default Unity collision matrix differs from the VRChat-correct one — always verify. Do NOT Load: references/audio-video.md, references/upload.md.

Performance

Target FPS

Critical Limits

Quest/Android Restrictions

Performance Optimization Workflow

If FPS is below target, follow this workflow — measure before guessing:

1. Measure
   ├── Unity Profiler: standard profiling in Play mode (primary; Deep Profile only for function-level deep dives — avoid on Quest, misleading results)
   ├── VRChat overlay: type "/perf" in-game
   └── Stats window: Draw Calls, Triangles, VRAM

2. Identify bottleneck category
   ├── CPU-bound (high Draw Calls): → Batching / LOD / Culling / Static flags
   ├── GPU-bound (shader cost): → Mirror / Realtime lights / Post-Processing
   ├── Memory (VRAM spikes): → Reduce texture resolution / video players
   └── Physics: → Disable Rigidbodies / Cloth / Constraints on Quest

3. Fix largest impact first, re-measure after each change
   (estimates below are typical ranges; actual gains vary by world complexity)
   Mirror ON by default    → Disable by default               (often -40-50% render cost)
   Realtime shadows        → Bake all lights                  (often -30-50% GPU cost)
   High lightmap resolution → Reduce and re-profile           (often -30-70% VRAM)
   Unbatched static objects → Mark as Static + enable batching (often -30-60% draw calls)
   Many active particles   → Pool; disable off-screen          (often -10-20% CPU)

Never stack multiple changes before re-measuring — you'll lose the ability to identify which change helped.

MANDATORY READ references/performance.md and references/lighting.md for Quest optimization. Run the profiling workflow above first to identify the bottleneck category before consulting references. Do NOT Load: references/audio-video.md, references/upload.md.

Lighting

Baked Lighting (Required)

✅ Recommended settings:
├── Lightmapper: Progressive GPU
├── Lightmap Resolution: 10-20 texels/unit
├── Light Mode: Baked or Mixed
└── Light Probes: Place along player paths

❌ Avoid:
├── Realtime lights (dynamic shadows)
├── High-resolution lightmaps (memory consumption)
└── Excessive Reflection Probes

MANDATORY READ references/lighting.md when configuring lightmaps or light probe placement. Do NOT Load: references/audio-video.md, references/upload.md, references/layers.md.

Audio & Video

VRC_SpatialAudioSource

Video Player Selection

MANDATORY READ references/audio-video.md for VRC_SpatialAudioSource or video player configuration. Do NOT Load: references/lighting.md, references/performance.md.

World Upload

Upload Steps

1. Check Validation
   └── VRChat SDK > Build Panel > Validations

2. Build & Test (local testing)
   └── "Build & Test New Build"
   └── Supports multi-client testing

3. Upload
   └── "Build and Upload"
   └── Set Content Warnings
   └── Set Capacity

4. Publish settings
   └── Configure public/private on the VRChat website

Pre-Upload Checklist

□ VRC_SceneDescriptor × 1
□ Spawns configured
□ Respawn Height appropriate
□ Layer/Collision Matrix verified
□ Light baking complete
□ Mirror default OFF
□ 45+ FPS in VR
□ No Validation errors
□ Content Warnings set
□ Capacity set

MANDATORY READ references/upload.md before running Build & Upload. Verify all pre-upload checklist items first. Do NOT Load: references/audio-video.md, references/lighting.md.

Troubleshooting

Diagnostic Router

Identify the symptom category, then follow the diagnostic path:

Physics / Collision

• Player walks through walls or floor

1. Did you run "Setup Layers for VRChat"? (SDK > Builder tab) - No → Run it. The default collision matrix blocks player↔environment collision. - Yes → Is the geometry on the Environment layer (11)? - No → Move all walkable surfaces, walls, and floors to layer 11. - Yes → Open Physics > Layer Collision Matrix: Environment × Player row must be ON.

• Pickup passes through floors / walls → Pickup must be on Pickup layer (13), not Default (0). In the collision matrix, Pickup × Environment must be ON.

Grab / Interaction

• Can't grab Pickup at all

1. Collider present? No → Add a Collider component. 2. Rigidbody present? No → Add a Rigidbody component. 3. VRC_Pickup component present? No → Add it.

• Pickup grabbed but immediately released → Check DisallowTheft on VRC_Pickup. If the current holder already owns it, a second grab may be blocked.

Sync / Network

• Pickup position doesn't update for other players → Add VRC_ObjectSync (requires Rigidbody). Without it, only the local client moves the object.
• Pickup returns to original position on drop → Ownership is not being transferred. Verify VRC_Pickup or UdonSharp script calls Networking.SetOwner before moving.

Seated / Station

• Can't sit in Station (no interaction prompt) → VRC_Station requires a Collider on the same or a child GameObject to register the interaction ray.
• Player clips into Station geometry after sitting → Adjust the Station Collision Transform field in the VRC_Station Inspector.

Mirror

• Mirror doesn't reflect players or world → Open VRC_MirrorReflection > Layers. Must include: Player (9), PlayerLocal (10), MirrorReflection (18), Environment (11).
• Mirror causes severe FPS drop → Remove unnecessary layers from the Layers mask, and ensure Mirror is OFF by default (see NEVER #1).

Build / Upload

• SDK build error in VRChat Control Panel → Builder tab lists all ⚠️ and ✖️ blockers with descriptions. Resolve each before building.
• "Missing script" on a UdonSharp component → The .cs file must have a matching .asset file. See the "missing.asset / script-asset pairing" rule in the unity-vrc-udon-sharp skill.

Editor / Runtime Discrepancy

• World works in Unity Editor Play mode but fails or behaves differently in VRChat → Unity Play mode does not replicate all SDK behaviors. Use "Build & Test New Build" (SDK > Builder tab) — this launches the actual VRChat client locally. Editor Play is useful only for quick UdonSharp iteration.
• Interactive UI element is visible but cannot be clicked in VRChat → VRC_UIShape on a Screen Space or Overlay Canvas (see NEVER #11). Set Canvas > Render Mode to World Space.

MANDATORY READ references/troubleshooting.md only if the Diagnostic Router above did not resolve the issue. Do NOT Load for non-troubleshooting tasks.

Related Skills

Templates (assets/templates/)

Starter templates for common SDK component patterns. Each template compiles without modification; adjust Inspector fields and extend the event stubs for your world.

References