[vtkusers] How to set a normal of a cell?

[David Doria]

On Mon, Jun 8, 2009 at 9:30 AM, vtklearny <msjean at gmx.de> wrote:

>
> Hello there,
>
> I'm still new to vtk and after some point manipulation I have to
> modify/update the normals.
>
> I found out that I can access the vtkCells , giving me 3 points in return.
> Then I can calculate a normal vector.
>
> But how do I set the vtkCell's(which is also a vtkTriangle) normal to my
> calculated one ?
> Is there something like this? : vtkCellData->setCellsNormal(cellId,
> normal);
>
> I thought there was a way to invoke automatic normal computation but never
> saw that working.
>
> Thanks for any help.
> I did not find an answer to this anywhere.
>
> the vtklearny
>

I just put this up on the wiki:
http://www.vtk.org/Wiki/Point_and_Cell_Normals

Is this what you are looking for?

The vtkPolyDataNormals class (demonstrated here:
http://www.vtk.org/Wiki/Extract_Normals_from_a_Polydata ) does what it
sounds like you are trying to do automatically.

Let us know if you have any more problems.

Thanks,

David
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