[vtkusers] Show/hide actors efficiently

[Nicolas Rannou]

Hi all,

I would like to show/hide actors which are:
   - behind or in front of a plane widget
   - inside or outside a box widget
and to be able to interact with the widgets in real time to modify the  
visibility of the actors.

My main issue is that I am working with thousands of actors and  
checking the bounding box of each actor appears not to be efficient  
enough...

Would somebody know a good way to deal with high number of actors?

Thanks,

     Nicolas