setFromCoplanarPoints method
Implementation
Plane setFromCoplanarPoints(Vector3 a, Vector3 b, Vector3 c) {
var normal = _vector1.subVectors(c, b).cross(_vector2.subVectors(a, b)).normalize();
// Q: should an error be thrown if normal is zero (e.g. degenerate plane)?
setFromNormalAndCoplanarPoint(normal, a);
return this;
}