code: def points(self, points):
          
          if not isinstance(points, np.ndarray):
              raise TypeError('Points must be a numpy array')
          # get the unique coordinates along each axial direction
          x = np.unique(points[:,0])
          y = np.unique(points[:,1])
          z = np.unique(points[:,2])
          nx, ny, nz = len(x), len(y), len(z)
          # TODO: this needs to be tested (unique might return a tuple)
          dx, dy, dz = np.unique(np.diff(x)), np.unique(np.diff(y)), np.unique(np.diff(z))
          ox, oy, oz = np.min(x), np.min(y), np.min(z)
          # Build the vtk object
          self._from_specs((nx,ny,nz), (dx,dy,dz), (ox,oy,oz))
          #self._point_ref = points
          self.Modified()
docs: set points without copying