[Paraview] XDMF reads as Multi-group Dataset

[David E DeMarle]

Hi Eric,

> 1. Any Xdmf file that can be read by ParaView (3.2.1 or 3.3) doesn't
> keep its intended data "Type" -- it's listed in the Information tab as
> "Multi-group Dataset". This can be reproduced by loading in a *.vti or
> *.vtu file, then save it as *.xmf and then re-read it. Is this a known
> issue? Any ideas for a workaround, even if it's just until Xdmf 2.0
> comes online?  (One resultant problem I'm having is that if I want to
> read in Xdmf and then save as a native VTK XML format, only the VTK
> Multi Group Files (*.vtm) format is listed.)

Berk can correct me if I am wrong, but that is a limitation of
Paraview. Once an atomic dataset is put into a composite data set, it
can't be pulled out back into the atomic dataset's type. We hope to
have it fixed for the upcoming 3.4 release. The new XDMF reader, which
I hope to have ready in a week or two, will produce atomic datasets
when there is only a single grid in the file.

>
> 2. Some of my data are particles, which I used to read in as an
> Unstructured Grid by using the Xdmf PolyVertex topology. Since these
> points are not really connected in any way, (up through ParaView
> 3.0.2) I used to start my *.xmf files like this, using just PolyVertex
> and NodesPerElement:

This sounds like a bug in the new XDMF library. You might want to ping
the xdmf mailing list (xdmf at lists.kitware.com) to see if any one is
aware of the issue, has a workaround or is working on a solution.
Perhaps the ARL group knows more than I.

good luck,
Dave