[vtkusers] Handling of vectors in VTK

[Aurelien Marsan]

Thank you David for your answer.
I am working with Python (and Paraview), so I will not modifiy the 
vtkTransformFilter.

The work around I have founded is to de-activate the active vector field
     data.GetPointData().SetActiveVectors(None)
Apply the transform filter, and then rotate the vectors thanks to the 
ArrayCalculator.

Maybe not the best way, but it works.

Thanks again,

--
Aurelien

On 03/06/2013 09:59 PM, David Gobbi wrote:
> That is correct, only a single array can be the "VECTORS" of the data
> set.  There is no way to get vtkTransformFilter to rotate more than
> one vector array at a time.
>
> Also note that the transformation always assumes that the vectors are
> contravariant vectors.
>
> If you are working in C++, then you can try modifying
> vtkTransformFilter so that you can specify the names of the arrays
> that you want to apply the vector transformation to.
>
>   - David
>
>
> On Wed, Mar 6, 2013 at 1:36 PM, Aurelien Marsan <aur.marsan at gmail.com> wrote:
>> Dear VTK users,
>>
>> I would like to have more informations about the handling of vectors in VTK.
>>
>> It seems to me that it is only possible to define a single PointData Array
>> as a vectors. Is that really the case ?
>> If yes, that lead to some major issues when using vtkTranformFilter : only
>> the array set as active Vectors is correctly handled. Could you then tell me
>> the right way to achieve the rotation ?
>>
>> Thanks in advance for your answer,
>>
>> Aurélien Marsan