Geometries

new THREE.BoxGeometry(
  width,          // default 1
  height,         // default 1
  depth,          // default 1
  widthSegments,  // default 1
  heightSegments, // default 1
  depthSegments   // default 1
);

new THREE.PlaneGeometry(width, height, widthSegments, heightSegments);
new THREE.CircleGeometry(radius, segments, thetaStart, thetaLength);
new THREE.RingGeometry(innerRadius, outerRadius, thetaSegments, phiSegments, thetaStart, thetaLength);

new THREE.SphereGeometry(
  radius,         // default 1
  widthSegments,  // longitude divisions (≥3, 32 looks smooth)
  heightSegments, // latitude divisions (≥2, 16 typical)
  phiStart,       // default 0
  phiLength,      // default Math.PI * 2
  thetaStart,     // default 0
  thetaLength     // default Math.PI
);

new THREE.CylinderGeometry(
  radiusTop,      // default 1
  radiusBottom,   // default 1
  height,         // default 1
  radialSegments, // default 32
  heightSegments, // default 1
  openEnded,      // default false
  thetaStart,     // default 0
  thetaLength     // default Math.PI * 2
);

new THREE.ConeGeometry(radius, height, radialSegments, heightSegments, openEnded, thetaStart, thetaLength);

new THREE.TorusGeometry(radius, tube, radialSegments, tubularSegments, arc);
new THREE.TorusKnotGeometry(radius, tube, tubularSegments, radialSegments, p, q);

new THREE.TetrahedronGeometry(radius, detail);
new THREE.OctahedronGeometry(radius, detail);
new THREE.IcosahedronGeometry(radius, detail);
new THREE.DodecahedronGeometry(radius, detail);

new THREE.CapsuleGeometry(radius, length, capSegments, radialSegments);

// ExtrudeGeometry — extrude a 2D Shape along a path
const shape = new THREE.Shape();
shape.moveTo(0, 0);
shape.lineTo(1, 0);
shape.lineTo(1, 1);
shape.lineTo(0, 1);
shape.closePath();

const extrudeSettings = {
  steps:          2,       // segments along the extrusion path
  depth:          0.5,     // extrusion depth
  bevelEnabled:   true,
  bevelThickness: 0.05,
  bevelSize:      0.03,
  bevelSegments:  3,
};
const geo = new THREE.ExtrudeGeometry(shape, extrudeSettings);

// ShapeGeometry — flat fill of a 2D Shape
const flatGeo = new THREE.ShapeGeometry(shape);

// LatheGeometry — revolution around the Y axis
const points = [
  new THREE.Vector2(0, 0),
  new THREE.Vector2(0.5, 0.5),
  new THREE.Vector2(0.3, 1),
  new THREE.Vector2(0, 1.2),
];
const lathe = new THREE.LatheGeometry(points, segments, phiStart, phiLength);

// TubeGeometry — tube along a Curve
const path  = new THREE.CatmullRomCurve3([
  new THREE.Vector3(-2, 0, 0),
  new THREE.Vector3(0,  2, 0),
  new THREE.Vector3(2,  0, 0),
]);
const tube = new THREE.TubeGeometry(path, tubularSegments, radius, radialSegments, closed);

const geo = new THREE.BufferGeometry();

// Vertices (flat Float32Array, 3 values per vertex)
const vertices = new Float32Array([
  -1, -1, 0,
   1, -1, 0,
   0,  1, 0,
]);
geo.setAttribute('position', new THREE.BufferAttribute(vertices, 3));

// Normals
const normals = new Float32Array([0, 0, 1,  0, 0, 1,  0, 0, 1]);
geo.setAttribute('normal', new THREE.BufferAttribute(normals, 3));

// UV coordinates
const uvs = new Float32Array([0, 0,  1, 0,  0.5, 1]);
geo.setAttribute('uv', new THREE.BufferAttribute(uvs, 2));

// Index (optional — reuse vertices)
const indices = new Uint16Array([0, 1, 2]);
geo.setIndex(new THREE.BufferAttribute(indices, 1));

// Colors (per-vertex) — needs vertexColors: true on material
const colors = new Float32Array([1,0,0, 0,1,0, 0,0,1]);
geo.setAttribute('color', new THREE.BufferAttribute(colors, 3));

// Recompute after manual edits
geo.computeVertexNormals();
geo.computeBoundingBox();
geo.computeBoundingSphere();

// Mark an attribute for GPU update
const posAttr = geo.getAttribute('position');
posAttr.array[i * 3]     = newX;
posAttr.array[i * 3 + 1] = newY;
posAttr.array[i * 3 + 2] = newZ;
posAttr.needsUpdate = true; // REQUIRED

// For partial updates (perf)
posAttr.updateRange.offset = 0;
posAttr.updateRange.count  = 3 * numChangedVertices;

// Center geometry at origin
geo.center();

// Translate/rotate/scale the geometry data itself (bakes transform)
geo.translate(0, -0.5, 0);
geo.rotateX(Math.PI / 2);
geo.scale(2, 2, 2);

// Normalize positions (fit inside unit sphere)
geo.normalize();

// Bounding info
geo.computeBoundingBox();
const box    = geo.boundingBox;    // THREE.Box3
const center = new THREE.Vector3();
box.getCenter(center);
const size   = new THREE.Vector3();
box.getSize(size);

// Merge multiple geometries
import { mergeGeometries } from 'three/addons/utils/BufferGeometryUtils.js';
const merged = mergeGeometries([geo1, geo2, geo3]);

// Dispose when done
geo.dispose();

const shape = new THREE.Shape();

// Drawing commands (like Canvas 2D)
shape.moveTo(x, y);
shape.lineTo(x, y);
shape.quadraticCurveTo(cpX, cpY, x, y);
shape.bezierCurveTo(cp1X, cp1Y, cp2X, cp2Y, x, y);
shape.arc(aX, aY, radius, startAngle, endAngle, clockwise);
shape.absarc(aX, aY, radius, startAngle, endAngle, clockwise);
shape.ellipse(aX, aY, xRadius, yRadius, startAngle, endAngle, clockwise, rotation);
shape.closePath();

// Holes
const hole = new THREE.Path();
hole.absarc(0.5, 0.5, 0.2, 0, Math.PI * 2, false);
shape.holes.push(hole);