Possible bug in how Paraview reads *.vtu (time stamp in particular)

Dear all,

I would like to report on a possible bug in how Paraview reads *.vtu datafiles – the time stamps in particular. I am having trouble reading in *.vtu data – even though I have checked that the time stamp contained in the variable Name=Time is correctly stated e.g. 0.00000, 5.00000E-03, etc. In fact, this variable appears not be recognized at all and it defaults to integer values which is simply the number of the file (I believe). Theses *.vtu files contains the locations (in time) of about 1000 particles releases in a flow field – hence the the ‘mesh’ is unstructured.

Secondly, I read an other of datafiles with *.nek5000 format (generated by the code nek5000, with file names like uniform0.f000001, etc.). This is a the usual structured type of datafile on a 2D mesh. The Time variable is correctly read in and there is no problem here. However, after applying the Temporal Shift Scale filter to the *.vtu data, I can produce movies from both datasets and run them together – but they appear to be slightly out of sync because extra data with the SAME time stamp appears to be created from the *.vtu data but only for some of the timesteps (e.g. time=0.25 is repeated). This is bizarre, and I believe that it must be a bug.

To summarize as succinctly as I can, here is the problem:

  1. par****.vtu files have correct timestamps on a variable named TIME, however, when the data is loaded into ParaView, that variable is not recognized, and integer numbers are assigned as time

  2. When using the filter “temporal Shift Scale,” it somewhat works, but on the time sequence of ParaView, some numbers appear repeated (additional snapshots appear); therefore, the data don’t quite sync correctly, particularly after those repeated times, everything appears shifted.

Please advise asap, needs urgent resolution.

Thank you
Nadeem

Please share dataset and steps to reproduce.

Please advise asap, needs urgent resolution.

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Thanks. I will prepare the datafiles, and also a zoom recording for you to view explaining the problem.
Where should I upload these files?

-nadeem

I have create a link where the data is stored and a video explaining what the problem is:

https://drive.google.com/drive/folders/1rTFSvnivOgR6zbP1fqyqeKYyxziXCEHf?usp=sharing

Thanks

Nadeem,

You might want to take a look at the PVD xml file format that would act as an index file to your *vtu files. Here you will have to create such a file and specify the correct “timestep” value for each file of your serie (corresponding to the content of your “TIME” field data array for each file).

Something like that (ex: data.pvd):

<?xml version="1.0"?>
<VTKFile type="Collection" version="0.1">
  <Collection>
    <DataSet timestep="0.5000000E-02" group="" part="0" file="bin00001.vtu"/>
    <DataSet timestep="0.1000000E-01" group="" part="0" file="bin00002.vtu"/>
    etc.
  </Collection>
</VTKFile>

Hope this helps.

J.

Can you tell me how to do this for a large number of files – I’ll want to do this for thousands of files.
Can someone produce a program that will will do this for me (I am nor familiar with OVD fornat etc).

Thanks

Yes, this is the kind of task that can be quite easily scripted in many languages.
You might want to consider some Kitware Support hours to quickly help you with all your issues.

Joachim