# Writing multiple time in the same file with vtkXMLPolyDataWriter

**URL:** https://discourse.vtk.org/t/writing-multiple-time-in-the-same-file-with-vtkxmlpolydatawriter/14697
**Category:** Support
**Tags:** code
**Created:** [October 10, 2024, 2:16pm UTC](https://discourse.vtk.org/t/writing-multiple-time-in-the-same-file-with-vtkxmlpolydatawriter/14697 "2024-10-10T14:16:53Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![Paul-Swann\_Puel](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/p/dec6dc/32.png) [@Paul-Swann\_Puel](https://discourse.vtk.org/u/Paul-Swann_Puel)
#### Post date: [October 10, 2024, 2:16pm UTC](https://discourse.vtk.org/t/writing-multiple-time-in-the-same-file-with-vtkxmlpolydatawriter/14697/1 "2024-10-10T14:16:53Z")

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Hi !

I have a code that write its data in a new .vtp file each time in order to be recognize as a sequence of time steps. Those data are PolyData wrote with XML.  
Is-it easily possible to change that to wrote multiple time in the same .vtp file, because the calculation server I use really dislike numerous little files and prefer one big file.

Sincerely,

Paul-Swann Puel

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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: [October 10, 2024, 2:21pm UTC](https://discourse.vtk.org/t/writing-multiple-time-in-the-same-file-with-vtkxmlpolydatawriter/14697/2 "2024-10-10T14:21:21Z")

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> [@Paul-Swann\_Puel](#):
>
> because the calculation server I use really dislike numerous little files and prefer one big file

This is indeed a limitation of the .vtp format. You may want to look into VTKHDF: [VTK File Formats - VTK documentation](https://docs.vtk.org/en/latest/design_documents/VTKFileFormats.html#vtkhdf-file-format)