    smoother = vtkWindowedSincPolyDataFilter()
    smoother.SetInputConnection(contour.GetOutputPort())
    smoother.SetNumberOfIterations(30)  # This has little effect on the error!
    # smoother.BoundarySmoothingOff()
    # smoother.FeatureEdgeSmoothingOff()
    # smoother.SetFeatureAngle(120.0)
--
    smoother = vtkWindowedSincPolyDataFilter()
    selector = vtkThreshold()
    scalars_off = vtkMaskFields()
    geometry = vtkGeometryFilter()
    writer = vtkXMLPolyDataWriter()

--
    smoother = vtkWindowedSincPolyDataFilter()
    smoother.SetInputConnection(discrete.GetOutputPort())
    smoother.SetNumberOfIterations(smoothing_iterations)
    smoother.BoundarySmoothingOff()
    smoother.FeatureEdgeSmoothingOff()
    smoother.SetFeatureAngle(feature_angle)
--
    smoother = vtkWindowedSincPolyDataFilter()
    smoother.SetInputConnection(iso_surface.GetOutputPort())
    smoother.SetNumberOfIterations(smoothing_iterations)
    smoother.BoundarySmoothingOff()
    smoother.FeatureEdgeSmoothingOff()
    smoother.SetFeatureAngle(feature_angle)
--
        smoother = vtkWindowedSincPolyDataFilter()
        smoother.SetInputConnection(last_connection.GetOutputPort())
        smoother.BoundarySmoothingOff()
        smoother.FeatureEdgeSmoothingOff()
        smoother.SetFeatureAngle(tissue['smooth_angle'])
        smoother.SetPassBand(tissue['smooth_factor'])
