Hi! I am running a simulation on a static, unstructured mesh. Currently I output the variables at every timestep using .vtu files, but it seems wasteful to output the mesh points & connectivity that many times since the mesh does not evolve.
Is it possible to point the .vtu file containing cell data to a separate points/connectivity file? And if so, what might that look like? Thank you!
You might want to take a look at the “.pvtu” format (https://kitware.github.io/vtk-examples/site/VTKFileFormats/). You might be able to use the indirection provided by the format (usually to read distributed datasets) to read your field and mesh files independently.
If that does not work, I would advise you to look into the XDMF format (XDMF Model and Format - XdmfWeb) supported by ParaView. While changing the format of your files may be cumbersome, this file format is really meant for the kind of storage optimizations you are describing.
Hi there @jfausty , I think you have a good point.
My understanding is that you are proposing to use a vtu file to hold all the geometry point information, another file to hold the field data at a particular moment, and then a pvtu file to link these files together.
However, I looked up the documentation and tutorials for the vtk library and didn’t find any relevant examples. The relevant functions of the vtkXMLPUnstructuredGridWriter class do not look like the functionality I want. Can you provide a simple example to show me how to do this?
Or, did you @nikic already achieved this, and could you show me your implementation?
Hi @metorm, I have not achieved this yet unfortunately, been occupied with other work! And @jfausty - a belated thank you for the suggestions!
I believe the .pvtu files allow you to combine several individual .vtu files. However as @metorm says, I don’t think VTK has the functionality to direct the points data to a separate file.
Had a brief look at xdmf - this might be closer to what I’m trying to achieve. It looks like you can include a points array in an .h5 file, and point the xdmf file to it. I haven’t seen an explicit example though, so that’s just a guess. Will update this thread if I try it successfully, please do the same!
Hi @metorm, that is a shame. As I said before, I’ll try at some point to use xdmf instead of vtu files, but it’s quite some effort so may take a while.
Side note - you might want to check out this plugin. It doesn’t address the problem of large data sizes, but it may help with paraview visualisation times. https://www.kitware.com/staticmeshplugin/