The change seems not been saved

Hi, thank you for your great work!
In the static_shape_model_invariance.py, Variable "points" has been changed, but Variable "polydata" was saved, which I think is the same with the original vtk and not changed during the procedure.
I wonder whether I have misunderstood the code, since the generate vtk I get from static_shape_model_invariance.py looks the same. 
Thank you!