[vtkusers] building cells from points

[G.Gao at cs.ucl.ac.uk]

It may be a very old question but I still couldn't find a proper solution. 
My question is rather simple: how to build cells within a polydata object, 
which contains only a list of points. I have tried to trianglurise the 
points by using the function vtkDelaunay3D. However, its output is an 
vtkAlgorithmOutput. I have no idea how to convert a vtkAlgorithmOutput to a 
polydata.

Cheers