[vtkusers] How to identify picked objects in a scene?

[stoeltze at isg.cs.uni-magdeburg.de]

Hi,

I have a scene consisting of a couple of actors which have all been
created based on vtkPolyData. I am able to pick those actors and to
retrieve a pointer to the associated vtkPolyData.

My problem is probably very simple to solve but I got stuck. How do I
determine which Actor, i.e. which vtkPolyData, has been picked? I would
like to assign something like a unique identifier to my vtkPolyDatas and
then, retrieve this identifier from the picked one. The following actions
shall be carried out then dependent on the ID of the picked one.

Any advice is deeply appreciated. Thank you very much.

Cheers,
Steffen