threejs-geometry

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• SKILL.md

SKILL.md (first lines)

# Three.js Geometry

Targets three.js r186. Examples use WebGLRenderer; the WebGPU and TSL section uses WebGPURenderer.

## Quick Start

```javascript
import * as THREE from "three";

const renderer = new THREE.WebGLRenderer({ antialias: true });
renderer.setPixelRatio(window.devicePixelRatio);
renderer.setSize(window.innerWidth, window.innerHeight);
document.body.appendChild(renderer.domElement);

const scene = new THREE.Scene();

const camera = new THREE.PerspectiveCamera(75, window.innerWidth / window.innerHeight, 0.1, 100);
camera.position.set(0, 0, 5);

// A geometry is the shape; many meshes can share one geometry instance
const mesh = new THREE.Mesh(new THREE.BoxGeometry(1, 1, 1), new THREE.MeshNormalMaterial());
scene.add(mesh);

renderer.setAnimationLoop(animate);

function animate() {
  mesh.rotation.y += 0.01;
  renderer.render(scene, camera);
}
```

## Built-in Geometries

### Basic Shapes

```javascript
new THREE.BoxGeometry(1, 1, 1); // width, height, depth, widthSegments, heightSegments, depthSegments
new THREE.SphereGeometry(1, 32, 16); // radius, widthSegments, heightSegments, phiStart, phiLength, thetaStart, thetaLength
new THREE.SphereGeometry(1, 32, 16, 0, Math.PI); // half sphere (phi sweep, cut through the poles)
new THREE.SphereGeometry(1, 32, 16, 0, Math.PI * 2, 0, Math.PI / 2); // dome (cut at the equator)
new THREE.PlaneGeometry(10, 10, 1, 1); // width, height, widthSegments, heightSegments
new THREE.CircleGeometry(1, 32); // radius, segments, thetaStart, thetaLength
new THREE.CylinderGeometry(1, 1, 2, 32); // radiusTop, radiusBottom, height, radialSegments, heightSegments, openEnded, thetaStart, thetaLength
new THREE.CylinderGeometry(1, 1, 2, 6); // hexagonal prism
new THREE.ConeGeometry(1, 2, 32); // radius, height, radialSegments, heightSegments, openEnded, thetaStart, thetaLength
new THREE.TorusGeometry(1, 0.4, 16, 100); // radius, tube, radialSegments, tubularSegments, arc, thetaStart, thetaLength
new THREE.TorusGeometry(1, 0.4, 16, 100, Math.PI); // half arc
new THREE.TorusKnotGeometry(1, 0.4, 100, 16, 2, 3); // radius, tube, tubularSegments, radialSegments, p, q
new THREE.RingGeometry(0.5, 1, 32, 1); // innerRadius, outerRadius, thetaSegments, phiSegments, thetaStart, thetaLength
```

### Advanced Shapes

```javascript
new THREE.CapsuleGeometry(0.5, 1, 4, 8, 1); // radius, height (the middle section only), capSegments, radialSegments, heightSegments

// radius, detail - each detail level subdivides every face
new THREE.IcosahedronGeometry(1, 0); // 20 faces at detail 0
new THREE.DodecahedronGeometry(1, 0);
new THREE.OctahedronGeometry(1, 0);
new THREE.TetrahedronGeometry(1, 0);

// Polyhedron - flat vertices array, indices, radius, detail
const vertices = [1, 1, 1, -1, -1, 1, -1, 1, -1, 1, -1, -1];
const indices = [2, 1, 0, 0, 3, 2, 1, 3, 0, 2, 3, 1];
new THREE.PolyhedronGeometry(vertices, indices, 1, 0);
```

### Path-Based Shapes

```javascript
// Lathe - a Vector2 profile rotated around the Y axis: points, segments, phiStart, phiLength
const profile = [
  new THREE.Vector2(0, 0), new THREE.Vector2(0.5, 0), new THREE.Vector2(0.5, 1), new THREE.Vector2(0, 1),
];
new THREE.LatheGeometry(profile, 32);

// Extrude - a 2D Shape pushed along Z
const shape = new THREE.Shape();
shape.moveTo(0, 0);
shape.lineTo(1, 0);
shape.lineTo(1, 1);
shape.lineTo(0, 1);
new THREE.ExtrudeGeometry(shape, {
  steps: 1, depth: 1, bevelEnabled: true,
  bevelThickness: 0.1, bevelSize: 0.1, bevelSegments: 3,
});

// Tube - a circular sweep along a curve: path, tubularSegments, radius, radialSegments, closed
const curve = new THREE.CatmullRomCurve3([
  new THREE.Vector3(-1, 0, 0), new THREE.Vector3(0, 1, 0), new THREE.Vector3(1, 0, 0),
]);
new THREE.TubeGeometry(curve, 64, 0.2, 8, false);
```

### Text Geometry

```javascript
import { FontLoader } from "three/addons/loaders/FontLoader.js";
import { TextGeometry } from "three/addons/geometries/TextGeometry.js";

// A .typeface.json font, from examples/fonts in the three.js repository
const font = await new FontLoader().loadAsync("fonts/helvetiker_regular.typeface.json");
const geometry = new TextGeometry("Hello", {
  font: font,
  size: 1, // text size in world units
  depth: 0.2, // extrusion depth
  curveSegments: 12,
  bevelEnabled: true,
  bevelThickness: 0.03,
  bevelSize: 0.02,
  direction: "ltr", // 'ltr', 'rtl' (right to left) or 'tb' (top to bottom)
});

geometry.center(); // recentre the glyphs on the origin
scene.add(new THREE.Mesh(geometry, new THREE.MeshNormalMaterial()));
```

## BufferGeometry

From CloudAI-X/threejs-skills, MIT.

More from CloudAI-X/threejs-skills