void BoundingBox::getBoundingBox(Eigen::Vector3f &min,
                                 Eigen::Vector3f &max) const {
  Eigen::Vector3f delta;
  for (int i = 0; i < delta.size(); ++i)
    delta[i] = 1.1 * range[i] * sigma[i];

  min = average - delta / 2.0;
  max = average + delta / 2.0;
}