Threejs scene setup
Skill gamedev-skills/awesome-gamedev-agent-skills/skills/web-engines/threejs-scene-setup
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Stand up a three.js scene: import maps and the three/addons path, the Scene/PerspectiveCamera/WebGLRenderer trio, the setAnimationLoop render loop, responsive resize, and OrbitControls. Use when starting or debugging a three.js app — when the user mentions three.js, THREE.Scene, WebGLRenderer, PerspectiveCamera, the render loop, resizing, or OrbitControls. For models use threejs-gltf-loading; for materials/lights use threejs-materials-lighting.
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SKILL.md
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three.js Scene Setup
Create the foundation of a three.js app: module loading, the scene/camera/renderer trio, the render loop, responsive resizing, and camera controls. Patterns target r165+ and are verified against r184.
When to use
- Use when bootstrapping a three.js scene, fixing a blank/black canvas, making the
canvas responsive, setting up the animation loop, or adding
OrbitControls. - Use when
package.jsondepends onthreeand code doesimport * as THREE from 'three'.
When not to use: loading .gltf/.glb models or skinned animation →
threejs-gltf-loading. Materials, lights, shadows, environment maps →
threejs-materials-lighting. 2D rendering → pixijs-rendering.
Core workflow
- Load three.js as an ES module with an import map. Since r147 the bare
specifier
'three'and'three/addons/'must be mapped (in HTML or by a bundler). Addons (controls, loaders) live underthree/addons/.... - Create the trio. A
Scene(root of the graph), aPerspectiveCamera(fov, aspect, near, far)moved back from the origin, and aWebGLRendererwhosedomElementis in the DOM. Set size andpixelRatio. - Add a mesh.
new Mesh(geometry, material)andscene.add(mesh). With a lit material you also need a light (seethreejs-materials-lighting). - Drive a render loop with
renderer.setAnimationLoop(fn). It's the modern, WebXR-/WebGPU-safe replacement for hand-rolledrequestAnimationFrame. Use aClockfor delta time. - Handle resize so the camera aspect and renderer match the canvas; update
camera.aspect, callupdateProjectionMatrix(), andrenderer.setSize(...). - Add
OrbitControlsfor orbit/pan/zoom while developing. Confirm something actually renders (a lit cube, the controls responding) before assuming success.
Patterns
1. HTML import map + module entry (no bundler)
<canvas id="c"></canvas>
<script type="importmap">
{
"imports": {
"three": "https://cdn.jsdelivr.net/npm/[email protected]/build/three.module.js",
"three/addons/": "https://cdn.jsdelivr.net/npm/[email protected]/examples/jsm/"
}
}
</script>
<script type="module" src="./main.js"></script>
With a bundler (Vite/webpack), skip the import map and just
npm i three; the same import statements resolve.
2. Scene + camera + renderer
// main.js
import * as THREE from 'three';
const canvas = document.querySelector('#c');
const renderer = new THREE.WebGLRenderer({ canvas, antialias: true });
renderer.setPixelRatio(Math.min(window.devicePixelRatio, 2)); // cap for perf
renderer.setSize(window.innerWidth, window.innerHeight);
const scene = new THREE.Scene();
scene.background = new THREE.Color(0x101018);
const camera = new THREE.PerspectiveCamera(
60, // vertical field of view (degrees)
window.innerWidth / window.innerHeight, // aspect
0.1, // near
100 // far
);
camera.position.set(3, 2, 5);
camera.lookAt(0, 0, 0);
const cube = new THREE.Mesh(
new THREE.BoxGeometry(1, 1, 1),
new THREE.MeshNormalMaterial() // unlit; shows orientation without a light
);
scene.add(cube);
3. The render loop (setAnimationLoop + Clock)
const clock = new THREE.Clock();
renderer.setAnimationLoop(() => {
const dt = clock.getDelta(); // seconds since last frame
cube.rotation.x += dt; // frame-rate independent
cube.rotation.y += dt * 0.7;
renderer.render(scene, camera);
});
// renderer.setAnimationLoop(null); // stop the loop
4. Responsive resize
function onResize() {
const w = window.innerWidth, h = window.innerHeight;
camera.aspect = w / h;
camera.updateProjectionMatrix(); // required after changing aspect
renderer.setSize(w, h);
}
window.addEventListener('resize', onResize);
5. OrbitControls (orbit / pan / zoom)
import { OrbitControls } from 'three/addons/controls/OrbitControls.js';
const controls = new OrbitControls(camera, renderer.domElement);
controls.enableDamping = true; // inertial feel
controls.target.set(0, 0, 0);
renderer.setAnimationLoop(() => {
controls.update(); // needed every frame when damping is on
renderer.render(scene, camera);
});
Pitfalls
Failed to resolve module specifier "three"→ missing import map (or bundler config). Map both"three"and"three/addons/"; addon paths must end with/.- Black canvas, no errors → camera is at the origin (inside/behind the object),
or you used a lit material (
MeshStandardMaterial) with no light. Move the camera back; useMeshNormalMaterial/MeshBasicMaterialto verify geometry first. - Nothing animates → you never called
renderer.renderinside the loop, or you callsetAnimationLoopbut render outside it. - Stretched / squashed view on resize → you resized the renderer but didn't
update
camera.aspect+updateProjectionMatrix(). - Blurry or jagged on HiDPI → set
renderer.setPixelRatio(...); cap it (≈2) so 4K/retina screens don't tank performance. - OrbitControls feel dead → with
enableDamping = trueyou must callcontrols.update()every frame. - Old tutorials use
<script src="three.min.js">→ since r147 three.js ships ES modules only; usetype="module"+ import maps.
References
- For coordinate conventions, the scene-graph (
Group, parent/child transforms,Object3Dadd/remove),OrthographicCamerafor 2.5D, and disposing of geometries/materials/textures to avoid leaks, readreferences/scene-graph.md.
Related skills
threejs-materials-lighting— give surfaces a lit look (lights, shadows, PBR).threejs-gltf-loading— load 3D models and play their animations.pixijs-rendering— 2D rendering in the browser.fps-shooter— a 3D genre template that composes three.js skills.