[vtkusers] Dynamically connected points

[nelson -]

hi all,
  i'm coding an interactive geomertry program in python using VTK. I
can't figure out how to make a Point that is dependant from the
position of the other points. I can to explain myself by an example.

If i wanto conconstruct the middle point of two points in the space i
have to build the middle point that change its position when i move
the two points... can i make it in vtl. I see vtkAssembly but i don't
understand if it is the right choice.

thanks,
  nelson