# Transient data for MultiBlockDataset in VTKHDF loads nothing
**URL:** https://discourse.paraview.org/t/transient-data-for-multiblockdataset-in-vtkhdf-loads-nothing/13837
**Category:** ParaView Support
**Created:** [January 31, 2024, 2:35pm UTC](https://discourse.paraview.org/t/transient-data-for-multiblockdataset-in-vtkhdf-loads-nothing/13837 "2024-01-31T14:35:11Z")
**Posts on this page:** 9
**Page:** 1
### Author:  [@Juan\_Jose\_Casafranca](https://discourse.paraview.org/u/Juan_Jose_Casafranca)
#### Post date: [January 31, 2024, 2:35pm UTC](https://discourse.paraview.org/t/transient-data-for-multiblockdataset-in-vtkhdf-loads-nothing/13837/1 "2024-01-31T14:35:11Z")
I am trying to load some transient data for my simulation. First of all, I am using a MultiBlockDataset and inside that MultiBlockDataSet, I have 3 UnstructuredGrids.
For that UnstructuredGrid, I have transient data. If I remove the transient data, I can correctly load the file and I see the meshes, but once I add the transient data, ParaView shows nothing (no geometry, no points)
Not sure what is wrong
This is my file
[Test.vtkhdf](https://discourse.paraview.org/uploads/short-url/9p1KNDalgjtGzEY6OMcQE9KXBdD.vtkhdf) (60.3 KB)
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [January 31, 2024, 2:39pm UTC](https://discourse.paraview.org/t/transient-data-for-multiblockdataset-in-vtkhdf-loads-nothing/13837/2 "2024-01-31T14:39:58Z")
@Lucas_Givord @Louis_Gombert
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### Author:  [@Louis\_Gombert](https://discourse.paraview.org/u/Louis_Gombert)
#### Post date: [January 31, 2024, 3:15pm UTC](https://discourse.paraview.org/t/transient-data-for-multiblockdataset-in-vtkhdf-loads-nothing/13837/3 "2024-01-31T15:15:12Z")
Hi @Juan_Jose_Casafranca , the support of composite types in VTKHDF Reader and Writer is still very new. For now, only the non-transient and non-parallel composite data can be read or written. We’ll post the current status of VTKHDF implementation on discourse soon.
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### Author:  [@Juan\_Jose\_Casafranca](https://discourse.paraview.org/u/Juan_Jose_Casafranca)
#### Post date: [January 31, 2024, 3:30pm UTC](https://discourse.paraview.org/t/transient-data-for-multiblockdataset-in-vtkhdf-loads-nothing/13837/4 "2024-01-31T15:30:34Z")
Are you totally sure about this? Apparently I was missing the CellsOffset dataset, but other than that, I have managed to load a VTKHDF file with compositve MutltiBlockDataSets and UnstructuredGrids as leafs with transient data.
Here is the file working
[Test.vtkhdf](https://discourse.paraview.org/uploads/short-url/1FfAKUVGVTliKeyoh2bouN1WMfa.vtkhdf) (68.4 KB)
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### Author:  [@Louis\_Gombert](https://discourse.paraview.org/u/Louis_Gombert)
#### Post date: [January 31, 2024, 3:34pm UTC](https://discourse.paraview.org/t/transient-data-for-multiblockdataset-in-vtkhdf-loads-nothing/13837/5 "2024-01-31T15:34:52Z")
I mean, not supported officially. We currently don’t have tests for composite + transient in VTK to validate the behavior and make sure it won’t change, but it’s totally possible that you can get it working somehow.
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### Author:  [@Juan\_Jose\_Casafranca](https://discourse.paraview.org/u/Juan_Jose_Casafranca)
#### Post date: [January 31, 2024, 3:36pm UTC](https://discourse.paraview.org/t/transient-data-for-multiblockdataset-in-vtkhdf-loads-nothing/13837/6 "2024-01-31T15:36:22Z")
Cool. Thanks! I will continue using it as I am right now, but I will mark the topic as solved, since this is still undocumented behavior.
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### Author:  [@Louis\_Gombert](https://discourse.paraview.org/u/Louis_Gombert)
#### Post date: [January 31, 2024, 3:37pm UTC](https://discourse.paraview.org/t/transient-data-for-multiblockdataset-in-vtkhdf-loads-nothing/13837/7 "2024-01-31T15:37:53Z")
Thanks for being an early adopter of the format, we’ll keep you posted when support is official!
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### Author:  [@Juan\_Jose\_Casafranca](https://discourse.paraview.org/u/Juan_Jose_Casafranca)
#### Post date: [January 31, 2024, 3:52pm UTC](https://discourse.paraview.org/t/transient-data-for-multiblockdataset-in-vtkhdf-loads-nothing/13837/8 "2024-01-31T15:52:48Z")
Your welcome. I have spent a long time searching for a format like VTKHDF, that could support transient + hierarchical data so I could store my simulations in a single file. I actually wrote something similar to what VTKHDF supports now and a ParaView plugin for reading it 🤣
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### Author:  [@Louis\_Gombert](https://discourse.paraview.org/u/Louis_Gombert)
#### Post date: [February 5, 2024, 12:41pm UTC](https://discourse.paraview.org/t/transient-data-for-multiblockdataset-in-vtkhdf-loads-nothing/13837/9 "2024-02-05T12:41:07Z")
the VTKHDF implementation status & roadmap is now public [VTKHDF roadmap - Development - VTK](https://discourse.vtk.org/t/vtkhdf-roadmap/13257)