def loadRectilinearGrid(filename):  # not tested
    """Load a ``vtkRectilinearGrid`` object from file and return a ``Actor(vtkActor)`` object."""
    reader = vtk.vtkRectilinearGridReader()
    reader.SetFileName(filename)
    reader.Update()
    gf = vtk.vtkRectilinearGridGeometryFilter()
    gf.SetInputConnection(reader.GetOutputPort())
    gf.Update()
    return Actor(gf.GetOutput())