[Paraview] Possible to view ExodusII HEX9 data?

[David Thompson]

Hi Weston,

Thanks for the report and the test data. I'll see that the fix gets merged in for both HEX9 and HEX21.

	David

> On Feb 12, 2018, at 10:31 AM, Weston Ortiz <weston at wortiz.com> wrote:
> 
> Using
> 
>   else if ((elemType.substr(0,3) == "HEX") && (binfo.BdsPerEntry[0] == 9))
>     { binfo.CellType=VTK_HEXAHEDRON;          binfo.PointsPerCell = 9; }
> 
> Appears to render correctly (see attached plot)
> 
> I changed the Points per cell to 9 as well, with it as 8 the output was the same as before.
> 
> I'm guessing this is because exodus stores arrays by element (e.g. [<values for element 1, nodes 1 to 9>, <values for element 2, nodes 1 to 9>, ... etc.]) and PointsPerCell is used to index into these
> 
> If so your hex21 might also need to be changed, cubit/trelis doesn't support hex21 so I couldn't check.
> 
> Thanks,
> 
> Weston
> 
> On Fri, Feb 9, 2018 at 4:16 PM, Weston Ortiz <weston at wortiz.com> wrote:
> > Have you built ParaView yourself or do you install it from packages.
> 
> Usually just from the paraview tarballs, i can try adding the new change code next week though.
> 
> > It would help to have a small example file for us to test against.
> 
> Attached is a small example file (lid driven cavity, ldc.exoII) and an example output image of a slice with velocity vectors in ensight
> 
> Thanks,
> 
> Weston
> 
> On Fri, Feb 9, 2018 at 3:17 PM, David Thompson <david.thompson at kitware.com> wrote:
> Hi Weston,
> 
> > Is there any way I could render HEX9 exodusii data as as HEX8 data in paraview,  (ignoring the 9th node) or work with it directly?
> 
> Not without modifying the source. Have you built ParaView yourself or do you install it from packages.
> 
> >
> > HEX9 numbering: https://github.com/gsjaardema/seacas/blob/master/docs/topology/hex09.png
> >
> > It appears that Paraview reads the file as HEX8 but is reading the center node as part of one of the hexahedron's edges (see attached image)
> 
> It would help to have a small example file for us to test against. If you want to experiment, you can edit VTK/IO/Exodus/vtkExodusIIReader.cxx around line 3237 (inside vtkExodusIIReaderPrivate::DetermineVtkCellType) and add
> 
>   else if ((elemType.substr(0,3) == "HEX") &&      (binfo.BdsPerEntry[0] == 9))
>     { binfo.CellType=VTK_HEXAHEDRON;               binfo.PointsPerCell = 8; }
> 
> You can see that is what we do for 21-node hexes currently.
> 
>         David
> 
> 
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> 
> <hex9plot.png>