N-faced polyhedra support for Xdmf

[aowen87]

Info about current / future support requested on the users list:-Hi, I was wondering if VisIt supports display of a N-faceed polyhedra via XDMF HDF5 format? If yes, can someone point me to an example of it. Thanks,Gautam.Note: I didn't have much luck browsing the Xdmf websites for info on polyherda.

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Ticket number: 1279 Status: Pending Project: VisIt Tracker: Feature Priority: Normal Subject: N-faced polyhedra support for Xdmf Assigned to: Eric Brugger Category: - Target version: - Author: Cyrus Harrison Start: 12/14/2012 Due date: % Done: 0% Estimated time: Created: 12/14/2012 11:45 am Updated: 09/12/2016 07:26 am Likelihood: Severity: Found in version: 2.12.3 Impact: 3 - Medium Expected Use: 3 - Occasional OS: All Support Group: Any Description: Info about current / future support requested on the users list:-Hi, I was wondering if VisIt supports display of a N-faceed polyhedra via XDMF HDF5 format? If yes, can someone point me to an example of it. Thanks,Gautam.Note: I didn't have much luck browsing the Xdmf websites for info on polyherda.

Comments: Jean Favre looked into this issue, and provided an example data set w/ nfaced cells:Hello CyrusI have done some research on this topic this afternoon because I have a user requesting the support of nfaced polygons.I have a working example in Xdmf of the socalled "Mixed" topology. I found out that VisIt (2.6) can read all Linear cells defined herehttp://www.xdmf.org/index.php/XDMF_Model_and_Formatexcept the nfaced shapes.Looking at the code in VisIt's Xdmf, I see no entry for the nfaces shapes.here are the only 3 types supported:avtXdmfFileFormat.C: case XDMF_POLYVERTEX:avtXdmfFileFormat.C: case XDMF_POLYLINE:avtXdmfFileFormat.C: case XDMF_POLYGON:the lack of definition of nface shapes comes from Xdmf itself as I understand it.For my usecase, the data come from STARCD ProSTAR. We can output it in Ensight format (including our nfaces 3D cells), and VisIt is happy with it.Hope this contributes to your understanding. I hope I have not overlooked something.CheersP.S. I have attached the data. The last element only is ignored by VisIt. That should be an 8faced cell = two pyramids sharing their base)Jean/CSCS Hi all,just as an follow up on this feature request: XDMF has now support for arbitrary polyhedral cells.The respective changes for XDMF and VTK are in commits 0a9fbd05 [1] and 802c9b61 [2] (see links below).VTK has an example XDMF file containing two polyhedral cells, which I attached also to this comment.Best regards,Armin[1] https://gitlab.kitware.com/xdmf/xdmf/commit/0a9fbd0590dff8a677c86754169cd2ccd72fe4b1[2] https://gitlab.kitware.com/vtk/vtk/commit/802c9b61de28e560c2659d2af76660bbb49c68be

[cyrush]

1287_polyhedron.xmf.zip 1287_prostar.h5.zip 1287_prostar.xmf.zip

[youngmit]

There still does not appear to be support in VisIt for the general polyhedra. I have produced an XDMF file that describes a bunch of hexagonal prisms, which Paraview happily renders just fine, but gives something like this in VisIt: It looks like it is interpreting the number of faces, and number of vertices per face as actual vertex indices, hence all of the edges running to the same point.

For comparison, I get this from Paraview:

Are there plans to support this?

[youngmit]

I was thinking about taking a stab at this myself. However, in the process of getting my build environment set up, I noticed that the XDMF dependency is version 2.1.1, which does not appear to have a Polyhedral cell type. Are general polyhedra new in XDMF version 3? Is there simply no XDMF 3 support in visit? I was pretty confident that I would be able to slip polyhedral cell support into the existing implementation without stubbing my toe on anything, but upgrading to Xdmf 3 seems like a little more than I can reasonably handle...