PVD with files with different meshes

Dear community,

I have a time series of node-centered data on rectangular grid with changing geometry. I create PVD file as follows:

<?xml version="1.0"?>
<VTKFile type="Collection" vesion="0.1">
  <Collection>
    <DataSet timestep="1" part="0" file="f1.vtx"/>
    <DataSet timestep="2" part="0" file="f2.vtx"/>
    <DataSet timestep="3" part="0" file="f3.vtx"/>
  </Collection>
</VTKFile>

Where x can be r, s, or u, since, I can save the data as RectilinearGrid, StructuredGrid, or UnstructuredGrid.

The problem is: when I step over data in ParaView, it does not update displayed geometry for cases of RectilinearGrid and StructuredGrid. Yet, ParaView re-reads files, since Information tab displays correct number of points/cells. In case of UnstructuredGrid geometry is updated. If I load individual VT(R|S|U) files, geometry is displayed correctly. The behaviour is the same for ParaView versions 5.6.2, 5.7.0, and 5.8.0.

I the behaviour a bug or a feature? I would prefer to save data as RectilinearGrid or as StructuredGrid, since they have implicit connectivity.

You can find example files in attached archive.

vtk-example.tar.gz (1.1 KB)

The WholeExtent cannot grow over multiple timesteps. This is definitely a bug or at least a limitation of the implementation. It has already been reported sometime ago :
https://gitlab.kitware.com/paraview/paraview/-/issues/12391

The simplest workaround is to add a “dummy” timestep at the begining that is the biggest possible in terms of extent.

Dear Mathieu,

Thank you for the reply.

The solution with “dummy” time step is interesting, yet I was not able to find in PVD documentation (https://www.paraview.org/Wiki/ParaView/Data_formats) a way to hide this time step (if it is possible at all).

Going from VTR/VTS to VTU solves the problem, increases file size, complicates code logic, but is acceptable solution.

yet I was not able to find in PVD documentation a way to hide this time step

Not possible afaik.