[vtkusers] Surface Normal Vectors

[David Doria]

On Mon, Nov 15, 2010 at 4:40 PM, SHACKELFORD Steve (AREVA)
<Steve.Shackelford at areva.com> wrote:
> Greetings,
>
> I have a laser line scanned surface created using triangle strips.  When I
> interrogate the input vtkPolyData, I find that I have 107639 points.  When I
> create the vtkPolyDataNormals, I find that this contains 108698 points --
> there is obviously not a one-to-one correlation between the input data and
> the output for the normal filter.  I understand that the vtkPolyDataNormals
> filter takes some liberties with the data to achieve a better visual
> presentation, but what I am interested in is an accurate association of the
> normal vectors with the original input data.
>
> Any suggestions?
>
> Regards,
>
> Steve Shackelford

Have you done:
normalGenerator->SetComputePointNormals(1);
normalGenerator->SetComputeCellNormals(0);
?

My guess is that the normals you are seeing are associated with the
cells (How many cells are there? Does it match the number of normals
you are seeing?).

David