fast-triangle-triangle-intersection

Fast and robust triangle-triangle intersection test with high precision for cross and coplanar triangles based on the algorithm by Devillers & Guigue ^[1].

• Uses Three.js
• Computes the intersection shape (point, line or polygon).
• Typescript definitions included.

Demo

Online Triangles Intersection demo

Install

npm i fast-triangle-triangle-intersection

Documentation

trianglesIntersect(t1: Triangle, t2: Triangle, target?: Array<Vector3>): Intersection

Computes wether triangle t1 and t2 are intersecting and returns Intersection.Cross if triangles are cross-intersecting, Intersection.Coplanar if triangles are coplanar-intersecting, otherwise returns null. If target array is given, it is emptied and intersection points are then computed and put in the array.

Example

Check if triangles are simply intersecting.

import {Triangle} from 'three';
import {trianglesIntersect, Intersection} from 'fast-triangle-triangle-intersection';

const t1 = new Triangle();
t1.a.set(-1, 0, 0);
t1.b.set(2, 0, -2);
t1.c.set(2, 0, 2);

const t2 = new Triangle();
t2.a.set(1, 0, 0);
t2.b.set(-2, -2, 0);
t2.c.set(-2, 2, 0);

const intersection = trianglesIntersect(t1, t2);
if (intersection === Intersection.Cross) {
  console.log("Triangles are cross-intersecting.");
} else if (intersection === Intersection.Coplanar) {
  console.log("Triangles are coplanar-intersecting.");
} else {
  console.log("Triangles are not intersecting.");
}

Obtening the intersection points.

const points = new Array<Vector3>();
if (trianglesIntersect(t1, t2, points)) {
  console.log("Intersection points: ", points); // [Vector3(1, 0, 0), Vector3(-1, 0, 0)]
}

Info

This algorithm is based on the publication by Devillers & Guigue ^[1].

@techreport{devillers:inria-00072100,
  TITLE = {{Faster Triangle-Triangle Intersection Tests}},
  AUTHOR = {Devillers, Olivier and Guigue, Philippe},
  URL = {https://hal.inria.fr/inria-00072100},
  NUMBER = {RR-4488},
  INSTITUTION = {{INRIA}},
  YEAR = {2002},
  MONTH = Jun,
  KEYWORDS = {LOW DEGREE PREDICATE ; COLLISION DETECTION ; GEOMETRIC PREDICATES},
  PDF = {https://hal.inria.fr/inria-00072100/file/RR-4488.pdf},
  HAL_ID = {inria-00072100},
  HAL_VERSION = {v1},
}