            skin_extractor = vtkFlyingEdges3D()
        except AttributeError:
            skin_extractor = vtkMarchingCubes()
    else:
        skin_extractor = vtkMarchingCubes()
    skin_extractor.SetInputConnection(reader.GetOutputPort())
--
            skin_extractor = vtkFlyingEdges3D()
        except AttributeError:
            skin_extractor = vtkMarchingCubes()
    else:
        skin_extractor = vtkMarchingCubes()
    skin_extractor.SetInputConnection(reader.GetOutputPort())
--
            bone_extractor = vtkFlyingEdges3D()
        except AttributeError:
            bone_extractor = vtkMarchingCubes()
    else:
        bone_extractor = vtkMarchingCubes()
    bone_extractor.SetInputConnection(reader.GetOutputPort())
--
            skin_extractor = vtkFlyingEdges3D()
        except AttributeError:
            skin_extractor = vtkMarchingCubes()
    else:
        skin_extractor = vtkMarchingCubes()
    skin_extractor.SetInputConnection(reader.GetOutputPort())
--
            bone_extractor = vtkFlyingEdges3D()
        except AttributeError:
            bone_extractor = vtkMarchingCubes()
    else:
        bone_extractor = vtkMarchingCubes()
    bone_extractor.SetInputConnection(reader.GetOutputPort())
--
            skin_extractor = vtkFlyingEdges3D()
        except AttributeError:
            skin_extractor = vtkMarchingCubes()
    else:
        skin_extractor = vtkMarchingCubes()
    skin_extractor.SetInputConnection(reader.GetOutputPort())
--
            mc = vtkFlyingEdges3D()
        except AttributeError:
            mc = vtkMarchingCubes()
    else:
        mc = vtkMarchingCubes()

--
            surface = vtkFlyingEdges3D()
        except AttributeError:
            surface = vtkMarchingCubes()
    else:
        surface = vtkMarchingCubes()
    surface.SetInputData(volume)
--
            iso = vtkFlyingEdges3D()
        except AttributeError:
            using_marching_cubes = True
            iso = vtkMarchingCubes()
    else:
        using_marching_cubes = True
--
            iso_surface = vtkFlyingEdges3D()
        except AttributeError:
            iso_surface = vtkMarchingCubes()
    else:
        iso_surface = vtkMarchingCubes()
    iso_surface.SetInputConnection(gaussian.GetOutputPort())
--
            iso_surface = vtkFlyingEdges3D()
        except AttributeError:
            iso_surface = vtkMarchingCubes()
    else:
        iso_surface = vtkMarchingCubes()
    iso_surface.SetInputConnection(select_tissue.GetOutputPort())
--
        iso_surface = vtkFlyingEdges3D()
        iso_surface.SetInputConnection(last_connection.GetOutputPort())
        iso_surface.ComputeScalarsOff()
        iso_surface.ComputeGradientsOff()
        iso_surface.ComputeNormalsOff()
        iso_surface.SetValue(0, iso_value)
--
            iso_sphere = vtkFlyingEdges3D()
        except AttributeError:
            iso_sphere = vtkMarchingCubes()
    else:
        iso_sphere = vtkMarchingCubes()
    iso_sphere.SetValue(0, 1.0)
