[vtkusers] How do I get the current state of a filter ?

[de Boer Ingo]

Hi,

I am using the vtkSurfaceReconstructionFilter with about 130000
to 250000 points. This takes quite some time. I want to show
some kind of progress bar or stdout or whatsoever which shows 
the current point number, so the user knows how long he has to
wait...

I have seen that there is something like a vtkProcessObject
and  vtkCallbackCommand. Are these the right ones to deal with?
I haven't found a sample on them  or on the thing I want to
do ?!

greets
  Ingo