[vtkusers] RequestInformation, RequestData and vtk filter, help needed

[Peter F Bradshaw]

Hi Markus;

Have you seen "Upgrading to and Understanding the New VTK Pipeline" at
http://www.cmake.org/cgi-bin/viewcvs.cgi/Utilities/Upgrading/TheNewVTKPipeline.pdf?rev=1.5

On Wed, 10 May 2006, Markus R wrote:

> Hi,
>
> I am trying to write a filter in vtk (also to be imported in ParaView later). But I find the documentation not so good. I have a good idea what I need to do, but the functions RequestData, RequestInformation, RequestUpdateExtent, and a few others are confusing me. It seems to me these functions are automatically called for when you apply a filter in the pipeline, but in what order? And what code should they contain?
>
> I have looked at the already many existing filters for vtk (and also paraview) and sometimes they use RequestInformation, but not always. RequestData seems always be implemented. Well, I am indeed lost without documentation what these functions really should do, what code they should contain, and when I should use them.
>
> What I basically want to do for my filter is to take an unstructured grid as input, then perform my algorithm, and have as output an image. Could someone kind explain a few lines about the functions mentioned above, or link me to any documentation that explains their use and purpose?
>
> Regards, Markus
>

Cheers

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Peter F Bradshaw, http://www.exadios.com
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