[vtkusers] Unstructured grid to structured grid?

[David Gobbi]

I'm not sure if I've understood, but if your original data already has
connectivity (i.e. faces), then why are you using vtkDelaunay2D at all?

On Wed, Sep 17, 2014 at 12:49 PM, Chris Marsh <chris.marsh at usask.ca> wrote:
> Hi all,
>
> Thanks for persevering with me. I got it working correctly with
> vtkPlaneSource.
>
> The problem ended up being a PEBKAC with how I was using the Delaunay2D
> class: When converting from CGAL to vtkUnstructuredgrid, you need to index
> the face values and vertices separately while maintaining connectivity.
> Because you are defining the connectivity, this works. However! with
> vtkDelaunay2D, you can't do this. Rather, for each vertex that is added to
> 'points', the face data must be added 3-times. Which this isn't quite
> perfect, it should work fine, unless there is a way of using an unstructured
> mesh and a probe filter?
> http://www.vtk.org/Wiki/VTK/Examples/Cxx/PolyData/GeometryFilter   suggests
> you can? So I will have to play around with that more.
>
> Thanks again, much appreciated.
>
> Chris Marsh
> PhD Student
> chrismarsh.ca
>
> 13 Kirk Hall
> University of Saskatchewan
>
> On Wed, Sep 17, 2014 at 11:00 AM, David Gobbi <david.gobbi at gmail.com> wrote:
>>
>> On Wed, Sep 17, 2014 at 10:45 AM, Chris Marsh <chris.marsh at usask.ca>
>> wrote:
>> > Hi David,
>> >
>> > Thanks for the reply, this is slowly starting to make sense. That call
>> > did
>> > in fact fix the bounds issues. However, the output still looks like it
>> > did
>> > in the above screenshot.
>> >
>> >>The plane is already composed of cells, so you should not run it
>> > through Delaunay.
>> >
>> > This is what perplexed me about the above linked example.
>> >
>> > What is the best way to write the probe results to a file then?
>>
>> At the beginning, I was hinting that you should probe with a
>> vtkImageData, which you could have written out as an image
>> (either as raw data, or as a png, etc).  But now that you have
>> the probed data as a polydata plane, you'll have to get the
>> scalars that are associated with the points that make up the
>> polydata.  GetPointData()->GetScalars() will return an array
>> that contains all the scalars.  See the VTK text for an in-depth
>> description of how data is stored in a VTK data set.
>>
>>  - David
>
>