[vtkusers] Filter source to file

[Antoine Dechaume]

Hi,

I am trying to create an animation, for which I need an object, let  
say a sphere, to move with time.
In a python script, I want to save the vtkSphereSource, at each time  
step, to a file (which will be used in paraview)
My only problem is that the writer (vtkXMLPolyDataWriter) wants a  
vtkDataObject. Is there an easy way to transform a vtkSphereSource  
instance to feed vtkXMLPolyDataWriter ?

Thanks,
Antoine.