threejs-animation

Three.js Motion (3D / WebGL)

Build real-time 3D motion for the web: animated scenes, camera moves, GLTF playback, instancing, scroll-linked 3D, and React Three Fiber. Optimize for smooth 60fps and clean disposal.

When to use

• 3D hero sections, product viewers, interactive/scroll-linked 3D backgrounds.
• Playing and blending GLTF animation clips.
• Rendering many objects efficiently (particle fields, tiles, forests).
• Camera fly-throughs and scroll-driven camera moves.

Minimal scene + render loop

import * as THREE from 'three';
const scene = new THREE.Scene();
const camera = new THREE.PerspectiveCamera(50, innerWidth / innerHeight, 0.1, 100);
camera.position.set(0, 0, 5);
const renderer = new THREE.WebGLRenderer({ antialias: true });
renderer.setSize(innerWidth, innerHeight);
renderer.setPixelRatio(Math.min(devicePixelRatio, 2));   // cap DPR — critical for retina perf
document.body.appendChild(renderer.domElement);

const mesh = new THREE.Mesh(
  new THREE.IcosahedronGeometry(1, 0),
  new THREE.MeshStandardMaterial({ color: 0x44aaff, flatShading: true })
);
scene.add(mesh, new THREE.DirectionalLight(0xffffff, 2).translateZ(5),
          new THREE.AmbientLight(0xffffff, 0.4));

const clock = new THREE.Clock();
renderer.setAnimationLoop(() => {
  const dt = clock.getDelta();
  mesh.rotation.y += dt * 0.5;                            // frame-rate independent
  renderer.render(scene, camera);
});
addEventListener('resize', () => {
  camera.aspect = innerWidth / innerHeight;
  camera.updateProjectionMatrix();
  renderer.setSize(innerWidth, innerHeight);
});

Use clock.getDelta() to make motion frame-rate independent (multiply rates by dt), and setAnimationLoop (works with WebXR and pauses on tab blur) instead of raw requestAnimationFrame.

GLTF animation clips

Load a model, play clips through an AnimationMixer, and update the mixer with delta time every frame.

import { GLTFLoader } from 'three/addons/loaders/GLTFLoader.js';
let mixer, actions = {};
new GLTFLoader().load('model.glb', (gltf) => {
  scene.add(gltf.scene);
  mixer = new THREE.AnimationMixer(gltf.scene);
  gltf.animations.forEach((clip) => { actions[clip.name] = mixer.clipAction(clip); });
  actions['Idle']?.play();
});
// In the loop: if (mixer) mixer.update(dt);