[vtkusers] Modification of a vtkActor and cell picking

[Vincent Arsigny]

Hi,

I'm currently visualizing some data with vtkPolyData, and there

First, I create an initial PolyData, which is rendered.
Then, I modify this PolyData by adding new cells, which are displayed
correctly in the render window.

The trouble is that when I use a vtkCellPicker after having modified the
PolyData, the system crashes because of a segmentation fault in the 
method GetCell().

I guess what is missing here is some king of updating procedure that 
must be done prior to the picking. Could any one give me a clue about this?
I've already tried losts of Modified() and Update() on all the objects
involved in this, but so far to no avail.

Cheers,

Vincent Arsigny
(Epidaure research Project, France)