Three.js

Overview

Guides building high-performance 3D web experiences with Three.js, WebGPU-first rendering, TSL (Three Shader Language), and React Three Fiber. Covers scene architecture, asset compression, draw call budgets, and React 19 / Next.js integration patterns.

When to use: Creating 3D scenes, WebGPU rendering setup, TSL shader authoring, asset optimization (Draco/KTX2), React Three Fiber composition, Next.js streaming for 3D content, loading GLTF models, setting up lighting and shadows, animation playback and blending.

When NOT to use: 2D canvas animations (use Canvas API), simple SVG graphics, server-side rendering without client hydration, projects targeting pre-2022 hardware exclusively.

Quick Reference

Pattern	API / Approach	Key Points
WebGPU renderer	`import * as THREE from 'three/webgpu'`	Must `await renderer.init()` before first render
R3F canvas	`<Canvas gl={...}>` with Suspense	Wrap in `<Suspense>` for streaming support
Frame updates	`useFrame((state, delta) => ...)`	Mutate refs directly; never use `setState`
TSL shaders	`import { ... } from 'three/tsl'`	Node-based; compiles to WGSL or GLSL
Instancing	`<instancedMesh>` with matrix updates	Single draw call for repeated geometry
Batched mesh	`BatchedMesh` (r156+)	Different geometries sharing one material
Draco compression	`gltf-pipeline -i in.gltf -o out.glb -d`	Up to 90% geometry size reduction
KTX2 textures	Basis Universal via `toktx`	Stays compressed in VRAM
LOD	`THREE.LOD` with distance thresholds	Swap detail levels by camera distance
On-demand render	`<Canvas frameloop="demand">`	Only render when scene state changes
Cleanup	`.dispose()` on unmount	Geometries, materials, and textures
Compute shaders	`Fn(() => {...})().compute(count)`	GPU-side physics, particles, flocking
Lighting	`DirectionalLight`, `SpotLight`, `HemisphereLight`	Enable `shadowMap` on renderer + `castShadow` on light
GLTF loading	`GLTFLoader` + `DRACOLoader`	Draco for geometry compression; traverse for shadows
Animation	`AnimationMixer` + `clipAction()`	Update with `clock.getDelta()` every frame
Crossfade	`action.fadeOut()` / `action.fadeIn()`	Weight-based blending between walk/run/idle
Environment maps	`RGBELoader` + `PMREMGenerator`	Set `scene.environment` for PBR reflections
Raycasting	`Raycaster.setFromCamera(pointer, cam)`	Mouse/touch picking; use `recursive: true` for GLTF
Morph targets	`mesh.morphTargetInfluences[index]`	Facial animation, blend shapes from GLTF

Common Mistakes

Mistake	Correct Pattern
Allocating `new THREE.Vector3()` or `new THREE.Color()` inside `useFrame`	Pre-allocate outside the loop to avoid GC pressure every frame
Using `requestAnimationFrame` manually in React projects	Use R3F's `useFrame` hook for frame-by-frame updates
Not awaiting `renderer.init()` for WebGPU	Always `await renderer.init()` before the first render to avoid race conditions
Loading assets without `<Suspense>` boundaries	Wrap `<Canvas>` in `<Suspense>` to prevent main thread blocking
Using high-poly models for background or distant elements	Use LOD (Level of Detail) or Impostors to reduce draw calls
Using `setState` inside render loop for animations	Mutate refs directly via `useFrame` for frame-by-frame updates
Speed tied to frame rate (`rotation += 0.01`)	Multiply by `delta` for frame-rate-independent motion
Not using `clock.getDelta()` for `mixer.update()`	Always pass delta time to `mixer.update(delta)` for correct animation speed
Forgetting to dispose loaded GLTF models	Traverse and dispose geometries, materials, and textures on removal
Shadow map enabled on renderer but not on the light	Set both `renderer.shadowMap.enabled` and `light.castShadow = true`
Large `far/near` ratio on camera	Keep ratio small to avoid z-fighting; set `near` as large as possible

Delegation

Asset and scene graph exploration: Use Explore agent
Multi-file scene refactoring and optimization passes: Use Task agent
3D architecture and rendering pipeline planning: Use Plan agent

threejs

Three.js

Overview

Quick Reference

Common Mistakes

Delegation

References