threejs-syntax-geometries

Create a BufferGeometry, set a position attribute with Float32BufferAttribute, optionally set an index buffer and UVs, then call computeVertexNormals for lighting. Always call computeBoundingSphere for frustum culling and dispose when removing the mesh.

Use InstancedMesh when rendering 100 or more copies of the same geometry, since it renders all instances in a single draw call. Below 10 instances, individual Mesh objects are fine; above 10,000, consider BatchedMesh or spatial subdivision.

The mesh renders black because the geometry lacks normal vectors required for lighting calculations. Call geometry.computeVertexNormals() after building custom geometry so lit materials can compute light interaction correctly.

Three.js does not automatically detect changes to typed arrays, so the GPU buffer stays stale. After modifying attribute data with setXYZ or direct array writes, set attribute.needsUpdate = true to re-upload the data.

No, the JavaScript garbage collector only frees JS objects, not GPU-side vertex buffers. You must explicitly call geometry.dispose() when permanently removing geometry from the scene to avoid GPU memory leaks.

Use indexed geometry for smooth-shaded meshes with shared vertices since it uses less memory and benefits from GPU vertex caching. Convert to non-indexed with toNonIndexed() only when you need per-face attributes like flat-shaded normals.