threejs-fast-raycast

A THREEjs utility for providing more efficient raycasts against sufficiently complex meshes.

Demo Here!

Casting 500 rays against an 80,000 polygon model at 60fps!

Use

import * as THREE from '.../three.js'
import '.../threejs-fast-raycasting.js'

// 80,000 polygon mesh
const geom = new THREE.TorusKnotBufferGeometry(10, 3, 400, 100);
const mesh = new THREE.Mesh(geom, material);
geom.computeBoundsTree();

// Fast raycasts!

Gotchas

• This is intended to be used with complicated, high-poly meshes. With less complex meshes, the benefits are negligible.
• Computing the bounds hierarchy is faster for THREE.BufferGeometry than it is for THREE.Geometry.
• The bounds hierarchy is not dynamic, so geometry that uses morph targets cannot be used.
• If the geometry is changed, then a call to computedBoundsTree() is required to update the bounds tree.

Approach

TODO

TODO

• Add option to basically devolve to an oct tree to speed up generation of tree
• Consider progressive generation of the tree, splitting nodes only when necessary
• Add option to take only the first hit to speed things up
• Use in conjunction with THREE Octtree for faster queries? Or do something similar