Hi Jason, Many thanks for your reply. In my case I'm not quite sure how attributes would help me, but I may not fully understand how they work. As I posted in the second xmf example file in my last email, given 4 nodes with 4 unique positions, I can completely define the plane topologically by writing the node numbers out in the correct order, their actual label/value/number doesn't matter (as long as it consistently refers to the correct position).
In my example I used [300 20 22 80] as the node labels to define a 2D plane. However, my current understanding of xdmf(2) is that I would need to supply in the geometry section (regardless of GeometryType) 301 x, y and z node positions (even if 297 are just zeros), just so that I could conform to the zero-based implicit numbering of that section. That allows paraview to index that data and pick out (the only) 4 positions it requires to define the plane. I'm asking whether there is a way round this so that, as I gave as an example in my second xmf file, one could additionally provide an explicit node number next to each x,y,z position so that the implicit zero-based numbering could be skipped and only 4 x,y,z positions needed to be added to the file in addition to their label/value/number. Can attributes do this? If so could you provide a quick example, ideally just with reference to the second example file I included in my email? Do you have a link to the xdmf(2) mail list? Many thanks again, Andy On 25 November 2013 16:13, Jason Fleming <jason.flem...@seahorsecoastal.com>wrote: > Hello Andy > > The XDMF2 library has the ability to assign Attributes and Information > data to Geometry objects. So you wouldn't be changing the node numbers, > you'd just be adding a new Attribute that has different values at each > node, and you'd need to display this new Attribute in Paraview instead of > the node numbers. > > Since you mentioned offsets for XDMF arrays: I've been working on an XDMF2 > implementation for ADCIRC, a finite element coastal ocean model. Being a > fortran code, ADCIRC uses 1-offset arrays, while the XDMF2 standard is > 0-offset. > > Its easy enough for us to subtract 1 from the node numbers in the element > table when storing mesh data as XDMF2, reversing the operation upon read > into ADCIRC or leaving them as-is for reading into Paraview. However, when > looking at node and element number labels on ADCIRC data in Paraview, the > analyst has to remember that all the displayed values are actually off by > 1. > > I emailed the XDMF mailing list and got a reply from the primary > developers that they were previously unaware of the demand for 1-offset > arrays, but they are now researching the possibility of adding this. > > Your case is a little different, since it seems you are interested in > arbitrary node numbering. But I thought I would mention the above > background info for completeness. As I said, XDMF2 Attributes may be the > solution for you. > > Cheers > Jason > > > > > > > On Mon, Nov 25, 2013 at 10:41 AM, Andrew Parker < > andy.john.par...@googlemail.com> wrote: > >> All, >> >> I thought I'd forward this onto the paraview list in case somebody could >> think of a way to do this? Please see my email below which I originally >> sent to the vtk user list. Any help would be very much appreciated, >> including the fact that it just cannot be done. I would in particular >> welcome thoughts from those who have helped develop the xdmf2 lib within >> the paraview source. >> >> Many thanks again, >> Andy >> >> ---------- Forwarded message ---------- >> Date: 23 November 2013 17:13 >> Subject: [vtkusers] Explicit numbering of nodes for Xdmf/h5 >> To: "vtkus...@vtk.org" <vtkus...@vtk.org> >> >> >> All, >> >> In an effort to spark some comments I thought I'd try to provide a small >> example for what I want to do in case my previous post (below) was unclear. >> Below is a valid xdmf file that paraview understands for a plane. >> >> <?xml version="1.0"?> >> <!DOCTYPE Xdmf SYSTEM "Xdmf.dtd"> >> <Xdmf xmlns:xi="http://www.w3.org/2003/XInclude" Version="2.2"> >> <Domain> >> <Grid GridType="Uniform"> >> <Topology TopologyType="Quadrilateral" Dimensions="1"> >> <DataItem Dimensions="1 4" NumberType="Int" Precision="8" >> Format="XML"> >> 0 1 3 2 >> </DataItem> >> </Topology> >> <Geometry GeometryType="XYZ"> >> <DataItem Dimensions="4 3" NumberType="Float" Precision="4" >> Format="XML"> >> -0.5 -0.5 0 >> 0.5 -0.5 0 >> -0.5 0.5 0 >> 0.5 0.5 0 >> </DataItem> >> </Geometry> >> </Grid> >> </Domain> >> </Xdmf> >> >> --- Now, what I want to do is to allow for the fact that the nodes >> defining this plane, may happen to be labelled 300, 20, 22, 80 instead of >> 0->3. The key point being that there is still only 4 nodes, not 300 in the >> file for which I only need 4 to define the geom, but need to write out 300 >> to all for the 0-based implicit ordering. Therefore, I'd like a section in >> the geom part of the xmf file to qualify this numbering. It doesn't bother >> me if they're subsequently renumbered inside paraview/vtk, only that I >> don't have to, as this is a simplistic version of something more >> complicated. So to be verbose, it should now look like: >> >> <?xml version="1.0"?> >> <!DOCTYPE Xdmf SYSTEM "Xdmf.dtd"> >> <Xdmf xmlns:xi="http://www.w3.org/2003/XInclude" Version="2.2"> >> <Domain> >> <Grid GridType="Uniform"> >> <Topology TopologyType="Quadrilateral" Dimensions="1"> >> <DataItem Dimensions="1 4" NumberType="Int" Precision="8" >> Format="XML"> >> * 300 20 22 80 * >> </DataItem> >> </Topology> >> <Geometry GeometryType="*XYZ_Explicit*"> >> <DataItem Dimensions="4 3" NumberType="Float" Precision="4" >> Format="XML"> >> * 20 -0.5 -0.5 0 * >> * 22 0.5 -0.5 0 * >> * 80 -0.5 0.5 0 * >> * 300 0.5 0.5 0 * >> </DataItem> >> </Geometry> >> </Grid> >> </Domain> >> </Xdmf> >> >> Can this be done, or could this be done in the future? Am I being daft >> and there is an easy way to do this? >> >> Cheers again, >> Andy >> >> >> >> _______________________________________________ >> Powered by www.kitware.com >> >> Visit other Kitware open-source projects at >> http://www.kitware.com/opensource/opensource.html >> >> Please keep messages on-topic and check the ParaView Wiki at: >> http://paraview.org/Wiki/ParaView >> >> Follow this link to subscribe/unsubscribe: >> http://www.paraview.org/mailman/listinfo/paraview >> >> > > > -- > Dr. Jason G. Fleming > Chief Engineer, Seahorse Coastal Consulting > 3103 Mandy Ln > Morehead City, NC 28557 > Tel: (252) 726-6323 > Mobile: (252) 269-0962 > Web: http://www.seahorsecoastal.com >
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