three-best-practices

name	three-best-practices
description	Three.js performance optimization and best practices guidelines. Use when writing, reviewing, or optimizing Three.js code. Triggers on tasks involving 3D scenes, WebGL/WebGPU rendering, geometries, materials, textures, lighting, shaders, or TSL.
license	MIT
metadata	{"author":"three-agent-skills","version":"2.0.0","three-version":"0.182.0+"}

Three.js Best Practices

Comprehensive performance optimization guide for Three.js applications. Contains 100+ rules across 17 categories, prioritized by impact.

Based on official guidelines from Three.js llms branch maintained by mrdoob.

When to Apply

Reference these guidelines when:

• Setting up a new Three.js project
• Writing or reviewing Three.js code
• Optimizing performance or fixing memory leaks
• Working with custom shaders (GLSL or TSL)
• Implementing WebGPU features
• Building VR/AR experiences with WebXR
• Integrating physics engines
• Optimizing for mobile devices

Rule Categories by Priority

Priority	Category	Impact	Prefix
0	Modern Setup & Imports	FUNDAMENTAL	setup-
1	Memory Management & Dispose	CRITICAL	memory-
2	Render Loop Optimization	CRITICAL	render-
3	Geometry & Buffer Management	HIGH	geometry-
4	Material & Texture Optimization	HIGH	material-
5	Lighting & Shadows	MEDIUM-HIGH	lighting-
6	Scene Graph Organization	MEDIUM	scene-
7	Shader Best Practices (GLSL)	MEDIUM	shader-
8	TSL (Three.js Shading Language)	MEDIUM	tsl-
9	Loading & Assets	MEDIUM	loading-
10	Camera & Controls	LOW-MEDIUM	camera-
11	Animation System	MEDIUM	animation-
12	Physics Integration	MEDIUM	physics-
13	WebXR / VR / AR	MEDIUM	webxr-
14	Audio	LOW-MEDIUM	audio-
15	Mobile Optimization	HIGH	mobile-
16	Production	HIGH	error-, migration-
17	Debug & DevTools	LOW	debug-

Quick Reference

0. Modern Setup (FUNDAMENTAL)

• setup-use-import-maps - Use Import Maps, not old CDN scripts
• setup-choose-renderer - WebGLRenderer (default) vs WebGPURenderer (TSL/compute)
• setup-animation-loop - Use renderer.setAnimationLoop() not manual RAF
• setup-basic-scene-template - Complete modern scene template

1. Memory Management (CRITICAL)

• memory-dispose-geometry - Always dispose geometries
• memory-dispose-material - Always dispose materials and textures
• memory-dispose-textures - Dispose dynamically created textures
• memory-dispose-render-targets - Always dispose WebGLRenderTarget
• memory-dispose-recursive - Use recursive disposal for hierarchies
• memory-dispose-on-unmount - Dispose in React cleanup/unmount
• memory-renderer-dispose - Dispose renderer when destroying view
• memory-reuse-objects - Reuse geometries and materials

2. Render Loop (CRITICAL)

• render-single-raf - Single requestAnimationFrame loop
• render-conditional - Render on demand for static scenes
• render-delta-time - Use delta time for animations
• render-avoid-allocations - Never allocate in render loop
• render-cache-computations - Cache expensive computations
• render-frustum-culling - Enable frustum culling
• render-update-matrix-manual - Disable auto matrix updates for static objects
• render-pixel-ratio - Limit pixel ratio to 2
• render-antialias-wisely - Use antialiasing judiciously

3. Geometry (HIGH)

• geometry-buffer-geometry - Always use BufferGeometry
• geometry-merge-static - Merge static geometries
• geometry-instanced-mesh - Use InstancedMesh for identical objects
• geometry-lod - Use Level of Detail for complex models
• geometry-index-buffer - Use indexed geometry
• geometry-vertex-count - Minimize vertex count
• geometry-attributes-typed - Use appropriate typed arrays
• geometry-interleaved - Consider interleaved buffers

4. Materials & Textures (HIGH)

• material-reuse - Reuse materials across meshes
• material-simplest-sufficient - Use simplest material that works
• material-texture-size-power-of-two - Power-of-two texture dimensions
• material-texture-compression - Use compressed textures (KTX2/Basis)
• material-texture-mipmaps - Enable mipmaps appropriately
• material-texture-anisotropy - Use anisotropic filtering for floors
• material-texture-atlas - Use texture atlases
• material-avoid-transparency - Minimize transparent materials
• material-onbeforecompile - Use onBeforeCompile for shader mods (or TSL)

5. Lighting & Shadows (MEDIUM-HIGH)

• lighting-limit-lights - Minimize dynamic lights
• lighting-bake-static - Bake lighting for static scenes
• lighting-shadow-camera-tight - Fit shadow camera tightly
• lighting-shadow-map-size - Choose appropriate shadow resolution
• lighting-shadow-selective - Enable shadows selectively
• lighting-shadow-cascade - Use CSM for large scenes
• lighting-probe - Use Light Probes

6. Scene Graph (MEDIUM)

• scene-group-objects - Use Groups for organization
• scene-layers - Use Layers for selective rendering
• scene-visible-toggle - Use visible flag, not add/remove
• scene-flatten-static - Flatten static hierarchies
• scene-name-objects - Name objects for debugging
• scene-object-pooling - Use object pooling

7. Shaders GLSL (MEDIUM)

• shader-precision - Use appropriate precision
• shader-avoid-branching - Minimize branching
• shader-precompute-cpu - Precompute on CPU
• shader-avoid-discard - Avoid discard, use alphaTest
• shader-texture-lod - Use textureLod for known mip levels
• shader-uniform-arrays - Prefer uniform arrays
• shader-varying-interpolation - Use flat when appropriate
• shader-chunk-injection - Use Three.js shader chunks

8. TSL - Three.js Shading Language (MEDIUM)

• tsl-why-use - Use TSL instead of onBeforeCompile
• tsl-setup-webgpu - WebGPU setup for TSL
• tsl-complete-reference - Full TSL type system and functions
• tsl-material-slots - Material node properties reference
• tsl-node-materials - Use NodeMaterial classes
• tsl-basic-operations - Types, operations, swizzling
• tsl-functions - Creating TSL functions with Fn()
• tsl-conditionals - If, select, loops in TSL
• tsl-textures - Textures and triplanar mapping
• tsl-post-processing - bloom, blur, dof, ao
• tsl-compute-shaders - GPGPU and compute operations
• tsl-glsl-to-tsl - GLSL to TSL translation

9. Loading & Assets (MEDIUM)

• loading-draco-compression - Use Draco for large meshes
• loading-gltf-preferred - Use glTF format
• gltf-loading-optimization - Full loader setup with DRACO/Meshopt/KTX2
• loading-progress-feedback - Show loading progress
• loading-async-await - Use async/await for loading
• loading-lazy - Lazy load non-critical assets
• loading-cache-assets - Enable caching
• loading-dispose-unused - Unload unused assets

10. Camera & Controls (LOW-MEDIUM)

• camera-near-far - Set tight near/far planes
• camera-fov - Choose appropriate FOV
• camera-controls-damping - Use damping for smooth controls
• camera-resize-handler - Handle resize properly
• camera-orbit-limits - Set orbit control limits

11. Animation (MEDIUM)

• animation-system - AnimationMixer, blending, morph targets, skeletal

12. Physics (MEDIUM)

• physics-integration - Rapier, Cannon-es integration patterns

13. WebXR (MEDIUM)

• webxr-setup - VR/AR buttons, controllers, hit testing

14. Audio (LOW-MEDIUM)

• audio-spatial - PositionalAudio, HRTF, spatial sound

15. Optimization (HIGH)

• mobile-optimization - Mobile-specific optimizations and checklist
• raycasting-optimization - BVH, layers, GPU picking

16. Production (HIGH)

• error-handling-recovery - WebGL context loss and recovery
• migration-checklist - Breaking changes by version

17. Debug (LOW)

• debug-stats - Use Stats.js
• debug-helpers - Use built-in helpers
• debug-gui - Use lil-gui for tweaking
• debug-renderer-info - Check renderer.info
• debug-conditional - Remove debug code in production

How to Use

Read individual rule files for detailed explanations and code examples:

rules/setup-use-import-maps.md
rules/memory-dispose-geometry.md
rules/tsl-complete-reference.md
rules/mobile-optimization.md

Each rule file contains:

• Brief explanation of why it matters
• BAD code example with explanation
• GOOD code example with explanation
• Additional context and references

Key Patterns

Modern Import Maps

<script type="importmap">
{
  "imports": {
    "three": "https://cdn.jsdelivr.net/npm/three@0.182.0/build/three.module.js",
    "three/addons/": "https://cdn.jsdelivr.net/npm/three@0.182.0/examples/jsm/",
    "three/tsl": "https://cdn.jsdelivr.net/npm/three@0.182.0/build/three.tsl.js"
  }
}
</script>

Proper Disposal

function disposeObject(obj) {
  if (obj.geometry) obj.geometry.dispose();
  if (obj.material) {
    if (Array.isArray(obj.material)) {
      obj.material.forEach(m => m.dispose());
    } else {
      obj.material.dispose();
    }
  }
}

TSL Basic Usage

import { texture, uv, color, time, sin } from 'three/tsl';

const material = new THREE.MeshStandardNodeMaterial();
material.colorNode = texture(map).mul(color(0xff0000));
material.colorNode = color(0x00ff00).mul(sin(time).mul(0.5).add(0.5));

Mobile Detection

const isMobile = /Android|iPhone|iPad|iPod/i.test(navigator.userAgent);
renderer.setPixelRatio(Math.min(window.devicePixelRatio, isMobile ? 1.5 : 2));