# Timestamp information not loaded from VTKHDF file
**URL:** https://discourse.paraview.org/t/timestamp-information-not-loaded-from-vtkhdf-file/15487
**Category:** ParaView Support
**Tags:** vtk
**Created:** [October 2, 2024, 6:00pm UTC](https://discourse.paraview.org/t/timestamp-information-not-loaded-from-vtkhdf-file/15487 "2024-10-02T18:00:09Z")
**Posts on this page:** 13
**Page:** 1
### Author:  [@jpmorr](https://discourse.paraview.org/u/jpmorr)
#### Post date: [October 2, 2024, 6:00pm UTC](https://discourse.paraview.org/t/timestamp-information-not-loaded-from-vtkhdf-file/15487/1 "2024-10-02T18:00:09Z")
In the `xml` `VTK` files you could store timestamp information in the `FieldData` by including a `DataArray` with the name `TimeValue`, which is really important when reading a group of files and need to add the timestamp to any figures or plots.
I’ve noticed that this doesn’t seem to work with `VTKHDF` files - if I create a `TimeValue` `DataSet` in the the `FieldData`, Paraview no longer reads this as the timestamp for this file. I’ve also checked in the spreadsheet view to see if the `FieldData` is being read but the table is empty so it appears that either Paraview doesn’t read `FieldData` from `VTKHDF` files or my file is not correct.
I’m not sure which is the case so I’ve attached a simple example where there should be some `FieldData`.
[temporal\_w=5dt\_t\_0.vtkhdf|attachment](https://discourse.paraview.org/uploads/short-url/kM8KoiRGv1k2YG5cqsDh1ZfpkYB.vtkhdf) (289.6 KB)
---
### Author:  [@Lucas\_Givord](https://discourse.paraview.org/u/Lucas_Givord)
#### Post date: [October 3, 2024, 9:34am UTC](https://discourse.paraview.org/t/timestamp-information-not-loaded-from-vtkhdf-file/15487/2 "2024-10-03T09:34:11Z")
Hello @jpmorr,
If you want to specify some timestamp data, you need to add a Steps group and to follow the doc here: [VTK File Formats - VTK documentation](https://docs.vtk.org/en/latest/design_documents/VTKFileFormats.html#temporal-data)
In anyway temporal image data should be supported
---
### Author:  [@jpmorr](https://discourse.paraview.org/u/jpmorr)
#### Post date: [October 3, 2024, 1:42pm UTC](https://discourse.paraview.org/t/timestamp-information-not-loaded-from-vtkhdf-file/15487/3 "2024-10-03T13:42:59Z")
@Lucas_Givord Does that mean the mechanism of a specific piece of `FieldData` to identify a time to paraview is not supported?
With regards the Steps in the documentation, is that not more for when you want to include multiple timesteps of data in a single `VTKHDF` file?
In my case, I have a single timestep per file since my data are usually quite large (often several hundred MB per timestep) and it would not make sense to have a single `VTKHDF` file that could be 10s or 100s of GB in size. So I would like to use the ability of Paraview to load a group of files with the time idinetified from the field data ([Field Data as Time Meta-Data in VTK XML File Formats - VTK documentation](https://docs.vtk.org/en/latest/design_documents/IOXMLTimeInFieldData.html)). Is the only way to create a step for a single timestep?
Also, I’m still not clear if `FieldData` is supported in `VTKHDF`, regardless of whether it is for a timestamp or not. In the file I uploaded, I cannot see any field data when loaded in Paraview - it does not appear in the list of variables or the spreadsheet view. Could there be a problem with the `VTKHDF` file or the Paraview file reader?
---
### Author:  [@Lucas\_Givord](https://discourse.paraview.org/u/Lucas_Givord)
#### Post date: [October 3, 2024, 1:48pm UTC](https://discourse.paraview.org/t/timestamp-information-not-loaded-from-vtkhdf-file/15487/4 "2024-10-03T13:48:41Z")
> Does that mean the mechanism of a specific piece of `FieldData` to identify a time to paraview is not supported?
TimeStep and TimeValue are special datasets and we treat it differently
> Also, I’m still not clear if `FieldData` is supported in `VTKHDF`
Do you use paraview master? If it’s the case then yes it should be supported
> So I would like to use the ability of Paraview to load a group of files
Yes, make sense. AFAIK we should be able to load a temporal data like that by relying on the `File Series` mechanism, @Louis_Gombert do you know if it’s still the case? Where we should put the time value in that case?
---
### Author:  [@jpmorr](https://discourse.paraview.org/u/jpmorr)
#### Post date: [October 3, 2024, 1:57pm UTC](https://discourse.paraview.org/t/timestamp-information-not-loaded-from-vtkhdf-file/15487/5 "2024-10-03T13:57:37Z")
I’m on paraview 5.13 at the moment as I assumed that since it was just released about a month ago it would be supported in that version. I can check the master version later - do I need to compile it or is there pre-compiled version available?
---
### Author:  [@Lucas\_Givord](https://discourse.paraview.org/u/Lucas_Givord)
#### Post date: [October 3, 2024, 2:02pm UTC](https://discourse.paraview.org/t/timestamp-information-not-loaded-from-vtkhdf-file/15487/6 "2024-10-03T14:02:16Z")
you can use a nightly build available in [paraview.org](http://paraview.org)
---
### Author:  [@cory.quammen](https://discourse.paraview.org/u/cory.quammen)
#### Post date: [October 3, 2024, 2:02pm UTC](https://discourse.paraview.org/t/timestamp-information-not-loaded-from-vtkhdf-file/15487/7 "2024-10-03T14:02:31Z")
Nightly builds are available at [https://www.paraview.org/download/?version=nightly](https://www.paraview.org/download/?version=nightly)
---
### Author:  [@jpmorr](https://discourse.paraview.org/u/jpmorr)
#### Post date: [October 3, 2024, 2:40pm UTC](https://discourse.paraview.org/t/timestamp-information-not-loaded-from-vtkhdf-file/15487/8 "2024-10-03T14:40:37Z")
I’ve just tried out the latest nightly build of paraview (5.13.1-572) but `FieldData` is still not loaded from my `VTKHDF` file. It seems like it may be that Paraview doesn’t yet support it?
---
### Author:  [@Lucas\_Givord](https://discourse.paraview.org/u/Lucas_Givord)
#### Post date: [October 3, 2024, 2:55pm UTC](https://discourse.paraview.org/t/timestamp-information-not-loaded-from-vtkhdf-file/15487/9 "2024-10-03T14:55:34Z")
you should be able to load and see an image data which contains field data in paraview master, could you please share me your data?
Also note that we support the compression so having 1 big file could be acceptable as workaround in your case
---
### Author:  [@jpmorr](https://discourse.paraview.org/u/jpmorr)
#### Post date: [October 4, 2024, 12:05pm UTC](https://discourse.paraview.org/t/timestamp-information-not-loaded-from-vtkhdf-file/15487/10 "2024-10-04T12:05:40Z")
I couldn’t find the `ImageData` example you mentioned, but I did find the can from the documentation ([VTK File Formats - VTK documentation](https://docs.vtk.org/en/latest/design_documents/VTKFileFormats.html#id2)) which is an unstructured grid and has `FieldData` for `NSTEPS`, `TMSTEPS` and `TimeValue`. These values are visible from the spreadsheet view, but not as properties for display. The `TimeValue` isn’t set
Checking this example helped me resolve the missing `FieldData` in my file - I was doing something stupid (passing a `None` value and then not writing any data to the file) so I can see that the field data is read by Paraview, just not set as a `TimeValue`.
Interestingly if you load the `can-pvtu.hdf` example you can see that it is trying to do something with the `NSTEPS`, `TMSTEPS` and `TimeValue` data as Paraview thinks there are 10 timesteps in the file with values between 0-1 for the times which isn’t quite correct for this example as it is only a single timestep from the exodus can example - probably the last one.
I did come across this GitLab issue ([https://gitlab.kitware.com/vtk/vtk/-/issues/18980](https://gitlab.kitware.com/vtk/vtk/-/issues/18980)) on the same topic where the poster mentioned including the timestep in `VTKHDF/Steps/Values`. Would that work here for the single timstep? It wasn’t clarified in the thread.
If I get the opportunity,I will test this for including the time for each file in a time series.
---
### Author:  [@jpmorr](https://discourse.paraview.org/u/jpmorr)
#### Post date: [October 4, 2024, 5:13pm UTC](https://discourse.paraview.org/t/timestamp-information-not-loaded-from-vtkhdf-file/15487/11 "2024-10-04T17:13:13Z")
I just tested a simple case of adding a `Steps` group with `NSteps` and `Values` to see if Paraview would pick that up for a single file but unfortunately not.
At least the `File Series` and `FieldData` work with the `VTKHDF` file format for now and hopefully at some point in the future `TimeValue` support gets added.
---
### Author:  [@Lucas\_Givord](https://discourse.paraview.org/u/Lucas_Givord)
#### Post date: [October 7, 2024, 6:34am UTC](https://discourse.paraview.org/t/timestamp-information-not-loaded-from-vtkhdf-file/15487/12 "2024-10-07T06:34:09Z")
Thanks for these investigations, it would be nice to open an issue regarding that, I don’t know how the XMLReader/FileSeriesReader proceed to append time value but maybe the HDFReader can do the same.
---
### Author:  [@jpmorr](https://discourse.paraview.org/u/jpmorr)
#### Post date: [October 25, 2024, 11:23am UTC](https://discourse.paraview.org/t/timestamp-information-not-loaded-from-vtkhdf-file/15487/13 "2024-10-25T11:23:42Z")
Thanks for the feedback. I’ll open an issue on this soon as some things have a work-around (for annotations you can select the field data) but if you use the plot over time function for a selection of cells or points, you can’t seem to set the x-axis variable as it’s only looking for the `TimeValue ` or `TMSTEPS ` that is supported in the `xml` formats.
I’m trying to transition my visualisation workflow to Paraview and I’m very slowly getting to grips with the various quirks of the `xml` and `vtkhdf` and `.pvd` files.