[vtkusers] link between a cell and its normal

[alexandre gouaillard]

hi everyone, i m stuck in what seems to be a very basic question, and it's
getting on my nerves.

I'd like to get the normal (which is allready computed, I checked) of a
specific cell of which I allready got the Id. Unfortunatly my knowledge of
the normal mechanism in vtk is so poor I can't manage to get it.

I got the cell ID, I managed to get all the normals through this (TCL code):
set normals [[[$Name GetOutput] GetCellData] GetNormals]

and then .... I don't know how to get my cell's normal out of the array.

Does someone know how  to do this ?

alex