containsVector3 method
Check if this contains a point.
Implementation
bool containsVector3(Vector3 point) {
  if (_plane0.distanceToVector3(point) < 0.0) {
    return false;
  }
  if (_plane1.distanceToVector3(point) < 0.0) {
    return false;
  }
  if (_plane2.distanceToVector3(point) < 0.0) {
    return false;
  }
  if (_plane3.distanceToVector3(point) < 0.0) {
    return false;
  }
  if (_plane4.distanceToVector3(point) < 0.0) {
    return false;
  }
  if (_plane5.distanceToVector3(point) < 0.0) {
    return false;
  }
  return true;
}