# Data consistency question regarding vtkhdf and OverlappingAMR

**URL:** https://discourse.vtk.org/t/data-consistency-question-regarding-vtkhdf-and-overlappingamr/16229
**Category:** Support
**Created:** [January 13, 2026, 12:07pm UTC](https://discourse.vtk.org/t/data-consistency-question-regarding-vtkhdf-and-overlappingamr/16229 "2026-01-13T12:07:37Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![PhilipDeegan](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/p/96bed5/32.png) [@PhilipDeegan](https://discourse.vtk.org/u/PhilipDeegan)
#### Post date: [January 13, 2026, 12:07pm UTC](https://discourse.vtk.org/t/data-consistency-question-regarding-vtkhdf-and-overlappingamr/16229/1 "2026-01-13T12:07:37Z")

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Hi there,

I’m wondering, does the OverlappingAMR VTKHDF format need to be padded with zeros or duplicate values for the case where a level might be missing across time?

For instance, if I write point data/boxes etc for a timestamp that has 2 levels

then a timestamp with 1 level as the refined level was dropped

then a timestamp with 2 levels again as the refined level returned.

I get the feeling there can be a data inconsistency without padding for the case with a missing level.

I hope this makes sense, if not, please let me know.

I have a plan to test this to confirm, but it would be nice to get an answer for you folks too

Thanks

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### Author: ![mwestphal](https://discourse.vtk.org/user_avatar/discourse.vtk.org/mwestphal/32/19_2.png) [@mwestphal](https://discourse.vtk.org/u/mwestphal)
#### Post date: [January 13, 2026, 12:25pm UTC](https://discourse.vtk.org/t/data-consistency-question-regarding-vtkhdf-and-overlappingamr/16229/2 "2026-01-13T12:25:02Z")

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@Louis_Gombert @lgivord PTAL

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### Author: ![lgivord](https://discourse.vtk.org/user_avatar/discourse.vtk.org/lgivord/32/3543_2.png) [@lgivord](https://discourse.vtk.org/u/lgivord)
#### Post date: [January 16, 2026, 3:25pm UTC](https://discourse.vtk.org/t/data-consistency-question-regarding-vtkhdf-and-overlappingamr/16229/3 "2026-01-16T15:25:18Z")

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hello @PhilipDeegan,

Indeed, when I added temporal support for overlapping AMR I didn’t take in account this use case where the number of level can change. A workaround for now is indeed to add some padding to 0.

tbh, I don’t think it would be complex to add some information in `/VTKHDF/Steps/LevelX/…` as attribute or (hdf) dataset to support it.

Do you think you can open an issue in VTK ? [https://gitlab.kitware.com/vtk/vtk/-/issues](https://gitlab.kitware.com/vtk/vtk/-/issues)