Function getNewellVector

src/utilities/geometry/Geometry.cpp:42–55

compute Newell vector from Point3dVector, direction is same as outward normal magnitude is twice the area

// compute Newell vector from Point3dVector, direction is same as outward normal
// magnitude is twice the area
OptionalVector3d getNewellVector(const Point3dVector& points) {
  OptionalVector3d result;
  const size_t N = points.size();
  if (N >= 3) {
    Vector3d vec;
    for (unsigned i = 1; i < N - 1; ++i) {
      const Vector3d v1 = points[i] - points[0];
      const Vector3d v2 = points[i + 1] - points[0];
      vec += v1.cross(v2);
    }
    result = vec;
  }
  return result;
}

// compute outward normal from Point3dVector
OptionalVector3d getOutwardNormal(const Point3dVector& points) {