[vtkusers] vtkCellDerivatives for polytopal surface mesh

[Jeff Lee]

Hi,
A polyhedron could be treated as a closed polygonal surface (or conversely
a closed polygonal surface could be considered an arbitrary polyhedron).
If you look at vtkPolyhedron.cxx you can see how it is using
MeanValueCoordinates to interpolate the function values inside the cell,
and then compute the derivatives.  So if your mesh contains polyhedral
cells, vtkCellDerivatives should work.

On Mon, May 8, 2017 at 5:38 PM, Kurt Sansom <kayarre at gmail.com> wrote:

> I do not understand your answer.
>
> ~Kurt
>
> On Mon, May 8, 2017 at 10:26 AM, Jeff Lee <jlee1549 at gmail.com> wrote:
>
>> Vtkpolyhedron uses mean value coordinates.
>>
>> On May 8, 2017 1:13 PM, "Kurt Sansom" <kayarre at gmail.com> wrote:
>>
>>> Hi,
>>>   Does anyone have suggestions to take cell derivatives from a
>>>  polyhedral/polytopal surface mesh because the VTK documentation says that,
>>> "derivatives calculated for polygons with more than 4 vertices are
>>> inaccurate in most cases"
>>>
>>> from: http://www.vtk.org/doc/nightly/html/classvtkCellDerivatives.
>>> html#details
>>>
>>>
>>> Regards,
>>> ~Kurt
>>>
>>> --
>>> Kurt Sansom
>>>
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>
>
> --
> Kurt Sansom
>
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