// Create simple, performant Three.js web apps/scenes (JS/TS, ES modules): scene/camera/renderer setup, lighting, geometries, materials, animation loop, resizing, OrbitControls, GLTF/GLB loading, and practical performance guardrails.
| name | threejs-builder |
| description | Create simple, performant Three.js web apps/scenes (JS/TS, ES modules): scene/camera/renderer setup, lighting, geometries, materials, animation loop, resizing, OrbitControls, GLTF/GLB loading, and practical performance guardrails. |
| metadata | {"short-description":"Build modern Three.js scenes."} |
A focused skill for creating small, performant Three.js web applications using modern ES module patterns.
Three.js is built on the scene graph—a hierarchical tree of objects where parent transformations affect children. Understanding this mental model is the fastest path to reliable 3D scenes.
Before creating a Three.js app, ask:
Core principles:
scene renders. Use Group for hierarchical transforms.requestAnimationFrame or renderer.setAnimationLoop.Prefer npm + bundler in real repos (Vite/React/etc.): npm i three and import from three and three/addons/.... Use CDN snippets only for truly single-file demos.
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Three.js App</title>
<style>
* { margin: 0; padding: 0; box-sizing: border-box; }
body { overflow: hidden; background: #000; }
canvas { display: block; }
</style>
</head>
<body>
<script type="module">
import * as THREE from 'https://unpkg.com/three@0.160.0/build/three.module.js';
// Scene setup
const scene = new THREE.Scene();
const camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 1000);
const renderer = new THREE.WebGLRenderer({ antialias: true });
renderer.setSize(window.innerWidth, window.innerHeight);
renderer.setPixelRatio(Math.min(window.devicePixelRatio, 2));
document.body.appendChild(renderer.domElement);
// Your 3D content here
// ...
camera.position.z = 5;
// Animation loop
renderer.setAnimationLoop(() => {
renderer.render(scene, camera);
});
// Handle resize
window.addEventListener('resize', () => {
camera.aspect = window.innerWidth / window.innerHeight;
camera.updateProjectionMatrix();
renderer.setSize(window.innerWidth, window.innerHeight);
});
</script>
</body>
</html>
Built-in primitives cover most simple app needs. Use BufferGeometry only for custom shapes.
Common primitives:
BoxGeometry(width, height, depth) - cubes, boxesSphereGeometry(radius, widthSegments, heightSegments) - balls, planetsCylinderGeometry(radiusTop, radiusBottom, height) - tubes, cylindersTorusGeometry(radius, tube) - donuts, ringsPlaneGeometry(width, height) - floors, walls, backgroundsConeGeometry(radius, height) - spikes, conesIcosahedronGeometry(radius, detail) - low-poly spheres (detail=0)Usage:
const geometry = new THREE.BoxGeometry(1, 1, 1);
const material = new THREE.MeshStandardMaterial({ color: 0x44aa88 });
const mesh = new THREE.Mesh(geometry, material);
scene.add(mesh);
Choose material based on lighting needs and visual style.
Material selection guide:
MeshBasicMaterial - No lighting, flat colors. Use for: UI, wireframes, unlit effectsMeshStandardMaterial - PBR lighting. Default for realistic surfacesMeshPhysicalMaterial - Advanced PBR with clearcoat, transmission. Glass, waterMeshNormalMaterial - Debug, rainbow colors based on normalsMeshPhongMaterial - Legacy, shininess control. Faster than StandardCommon material properties:
{
color: 0x44aa88, // Hex color
roughness: 0.5, // 0=glossy, 1=matte (Standard/Physical)
metalness: 0.0, // 0=non-metal, 1=metal (Standard/Physical)
emissive: 0x000000, // Self-illumination color
wireframe: false, // Show edges only
transparent: false, // Enable transparency
opacity: 1.0, // 0=invisible, 1=opaque (needs transparent:true)
side: THREE.FrontSide // FrontSide, BackSide, DoubleSide
}
No light = black screen (except BasicMaterial/NormalMaterial).
Light types:
AmbientLight(intensity) - Base illumination everywhere. Use 0.3-0.5DirectionalLight(color, intensity) - Sun-like, parallel rays. Cast shadowsPointLight(color, intensity, distance) - Light bulb, emits in all directionsSpotLight(color, intensity, angle, penumbra) - Flashlight, cone of lightTypical lighting setup:
const ambientLight = new THREE.AmbientLight(0xffffff, 0.4);
scene.add(ambientLight);
const mainLight = new THREE.DirectionalLight(0xffffff, 1);
mainLight.position.set(5, 10, 7);
scene.add(mainLight);
const fillLight = new THREE.DirectionalLight(0x88ccff, 0.5);
fillLight.position.set(-5, 0, -5);
scene.add(fillLight);
Shadows (advanced, use when needed):
renderer.shadowMap.enabled = true;
renderer.shadowMap.type = THREE.PCFSoftShadowMap;
mainLight.castShadow = true;
mainLight.shadow.mapSize.width = 2048;
mainLight.shadow.mapSize.height = 2048;
mesh.castShadow = true;
mesh.receiveShadow = true;
Transform objects over time using the animation loop.
Animation patterns:
renderer.setAnimationLoop((time) => {
mesh.rotation.x = time * 0.001;
mesh.rotation.y = time * 0.0005;
renderer.render(scene, camera);
});
renderer.setAnimationLoop((time) => {
mesh.position.y = Math.sin(time * 0.002) * 0.5;
renderer.render(scene, camera);
});
const mouse = new THREE.Vector2();
window.addEventListener('mousemove', (event) => {
mouse.x = (event.clientX / window.innerWidth) * 2 - 1;
mouse.y = -(event.clientY / window.innerHeight) * 2 + 1;
});
renderer.setAnimationLoop(() => {
mesh.rotation.x = mouse.y * 0.5;
mesh.rotation.y = mouse.x * 0.5;
renderer.render(scene, camera);
});
Import OrbitControls from examples for interactive camera movement.
Bundler (npm) import:
import { OrbitControls } from 'three/addons/controls/OrbitControls.js';
CDN import:
<script type="module">
import * as THREE from 'https://unpkg.com/three@0.160.0/build/three.module.js';
import { OrbitControls } from 'https://unpkg.com/three@0.160.0/examples/jsm/controls/OrbitControls.js';
// ... scene setup ...
const controls = new OrbitControls(camera, renderer.domElement);
controls.enableDamping = true;
controls.dampingFactor = 0.05;
renderer.setAnimationLoop(() => {
controls.update();
renderer.render(scene, camera);
});
</script>
const geometry = new THREE.BoxGeometry(1, 1, 1);
const material = new THREE.MeshStandardMaterial({ color: 0x00ff88 });
const cube = new THREE.Mesh(geometry, material);
scene.add(cube);
renderer.setAnimationLoop((time) => {
cube.rotation.x = time * 0.001;
cube.rotation.y = time * 0.001;
renderer.render(scene, camera);
});
const particleCount = 1000;
const geometry = new THREE.BufferGeometry();
const positions = new Float32Array(particleCount * 3);
for (let i = 0; i < particleCount * 3; i += 3) {
positions[i] = (Math.random() - 0.5) * 50;
positions[i + 1] = (Math.random() - 0.5) * 50;
positions[i + 2] = (Math.random() - 0.5) * 50;
}
geometry.setAttribute('position', new THREE.BufferAttribute(positions, 3));
const material = new THREE.PointsMaterial({ color: 0xffffff, size: 0.1 });
const particles = new THREE.Points(geometry, material);
scene.add(particles);
// Background grid
const gridHelper = new THREE.GridHelper(50, 50, 0x444444, 0x222222);
scene.add(gridHelper);
// Foreground object
const mainGeometry = new THREE.IcosahedronGeometry(1, 0);
const mainMaterial = new THREE.MeshStandardMaterial({
color: 0xff6600,
flatShading: true
});
const mainMesh = new THREE.Mesh(mainGeometry, mainMaterial);
scene.add(mainMesh);
Three.js uses hexadecimal color format: 0xRRGGBB
Common hex colors:
0x000000, White: 0xffffff0xff0000, Green: 0x00ff00, Blue: 0x0000ff0x00ffff, Magenta: 0xff00ff, Yellow: 0xffff000xff8800, Purple: 0x8800ff, Pink: 0xff0088❌ Not importing OrbitControls from correct path
Why bad: Controls won't load, THREE.OrbitControls is undefined in modern Three.js
Better: Use import { OrbitControls } from 'three/addons/controls/OrbitControls.js' or the correct CDN examples/jsm path
❌ Forgetting to add object to scene
Why bad: Object won't render, silent failure
Better: Always call scene.add(object) after creating meshes/lights
❌ Using old requestAnimationFrame pattern instead of setAnimationLoop
Why bad: More verbose, doesn't handle XR/WebXR automatically
Better: renderer.setAnimationLoop((time) => { ... })
❌ Creating new geometries in animation loop Why bad: Massive memory allocation, frame rate collapse Better: Create geometry once, reuse it. Transform only position/rotation/scale
❌ Using too many segments on primitives
Why bad: Unnecessary vertices, GPU overhead
Better: Default segments are usually fine. SphereGeometry(1, 32, 16) not SphereGeometry(1, 128, 64)
❌ Not setting pixelRatio cap
Why bad: 4K/5K displays run at full resolution, poor performance
Better: Math.min(window.devicePixelRatio, 2)
❌ Everything in one giant function
Why bad: Hard to modify, hard to debug
Better: Separate setup into functions: createScene(), createLights(), createMeshes()
❌ Hardcoding all values
Why bad: Difficult to tweak and experiment
Better: Define constants at top: const CONFIG = { color: 0x00ff88, speed: 0.001 }
IMPORTANT: Each Three.js app should feel unique and context-appropriate.
Vary by scenario:
Vary visual elements:
Avoid converging on:
Three.js is a tool for interactive 3D on the web.
Effective Three.js apps:
Modern Three.js (r150+) uses ES modules from three package or CDN. CommonJS patterns and global THREE variable are legacy.
For advanced topics (GLTF models, shaders, post-processing), see references/advanced-topics.md.
Codex is capable of creating elegant, performant 3D web experiences. These patterns guide the way—they don't limit the result.
For game development (state machines, screen effects, animation switching, parallax), see references/game-patterns.md.
Creates simple Three.js web apps with scene setup, lighting, geometries, materials animations, and responsive rendering. Use for: "Create a threejs scene/app/showcase" or when user wants 3D web content. Supports ES modules, modern Three.js r150+ APIs.
Build and ship Three.js apps on Capacitor iOS with Vite and Swift Package Manager: GLTF loading, assets_index animation UI, OrbitControls mouse/touch mappings, and iOS sync/run troubleshooting.