visualizing vtkExporter.exportSpheres with paraview

Hi,
Apologies if this was asked/answered already, I wasnt able to find an answer.

I would like to visualize in paraview a packing of spheres, (available: http://pasteall.org/1008590)

However when I load the vtk file in paraview I am unable to see the spheres. (The vtk export from yade includes a list of locations and radii, however doesnt paraview need a list of vertices and faces?) Is there perhaps a script needed to generate the spherical geometry?

many thanks
Jesse