static const Vector<GLdouble, 3> _face_vec( GLuint face, const Vector<GLdouble, 3> vec ) { return _face_mat(face)*vec; }
GLuint _face_divs(GLuint face, GLuint axis) const { return GLuint(std::fabs(Dot(_face_mat(face).Row(axis), _divs))); }
double _face_barw(GLuint face, GLuint axis) const { return std::fabs(Dot(_face_mat(face).Row(axis), _barw)); }
double _face_size(GLuint face, GLuint axis) const { return std::fabs(Dot(_face_mat(face).Row(axis), _size)); }