threejs-geometry

# Three.js Geometry ## When to Use - You need to create or optimize geometry in Three.js. - The task involves built-in shapes, custom `BufferGeometry`, vertices, or instanced rendering. - You are working on mesh structure rather than scene setup or materials alone. ## Quick Start ```javascript import * as THREE from "three"; // Built-in geometry const box = new THREE.BoxGeometry(1, 1, 1); const sphere = new THREE.SphereGeometry(0.5, 32, 32); const plane = new THREE.PlaneGeometry(10, 10); // Create mesh const material = new THREE.MeshStandardMaterial({ color: 0x00ff00 }); const mesh = new THREE.Mesh(box, material); scene.add(mesh); ``` ## Built-in Geometries ### Basic Shapes ```javascript // Box - width, height, depth, widthSegments, heightSegments, depthSegments new THREE.BoxGeometry(1, 1, 1, 1, 1, 1); // Sphere - radius, widthSegments, heightSegments, phiStart, phiLength, thetaStart, thetaLength new THREE.SphereGeometry(1, 32, 32); new THREE.SphereGeometry(1, 32, 32, 0, Math.PI * 2, 0, Math.PI); // Full sphere new THREE.SphereGeometry(1, 32, 32, 0, Math.PI); // Hemisphere // Plane - width, height, widthSegments, heightSegments new THREE.PlaneGeometry(10, 10, 1, 1); // Circle - radius, segments, thetaStart, thetaLength new THREE.CircleGeometry(1, 32); new THREE.CircleGeometry(1, 32, 0, Math.PI); // Semicircle // Cylinder - radiusTop, radiusBottom, height, radialSegments, heightSegments, openEnded new THREE.CylinderGeometry(1, 1, 2, 32, 1, false); new THREE.Cylind...