    delaunay1 = vtkDelaunay3D()
    delaunay1.SetInputConnection(sphereSource1.GetOutputPort())
    delaunay1.Update()

    sphereSource2 = vtkSphereSource()
    sphereSource2.SetCenter(5, 0, 0)
--
    delaunay2 = vtkDelaunay3D()
    delaunay2.SetInputConnection(sphereSource2.GetOutputPort())
    delaunay2.Update()

    appendFilter = vtkAppendFilter()
    appendFilter.AddInputConnection(delaunay1.GetOutputPort())
--
tri = vtk.vtkDelaunay3D()
tri.SetInputConnection(cube.GetOutputPort())
tri.BoundingTriangulationOff()

# vtkImplicitDataSet needs some scalars to interpolate to find inside/outside
elev = vtk.vtkElevationFilter()
