# one file to merge them all

**URL:** https://discourse.vtk.org/t/one-file-to-merge-them-all/14671
**Category:** Support
**Tags:** file-formats
**Created:** [October 6, 2024, 9:28pm UTC](https://discourse.vtk.org/t/one-file-to-merge-them-all/14671 "2024-10-06T21:28:15Z")
**Posts on this page:** 5
**Page:** 1

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### Author: ![Xtof](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/x/c0e974/32.png) [@Xtof](https://discourse.vtk.org/u/Xtof)
#### Post date: [October 6, 2024, 9:28pm UTC](https://discourse.vtk.org/t/one-file-to-merge-them-all/14671/1 "2024-10-06T21:28:15Z")

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Hi there,  
thanks for the job.  
I work with features, stored as unstructured grid (+there data). Is it possible to store each feature on its own single file, and have a “main vtk file” that list them all ?

that would give me a folder with files like :

- feature1.vtk
- feature2.vtk
- …

and a main file with links to these (sub-)files ?

I hope I am clear enough.  
thanks for your time  
Ch.

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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 7, 2024, 6:58am UTC](https://discourse.vtk.org/t/one-file-to-merge-them-all/14671/2 "2024-10-07T06:58:13Z")

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Can you clarify which data do you want to separate and what you mean by “feature” ?

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### Author: ![Xtof](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/x/c0e974/32.png) [@Xtof](https://discourse.vtk.org/u/Xtof)
#### Post date: [October 7, 2024, 7:15am UTC](https://discourse.vtk.org/t/one-file-to-merge-them-all/14671/3 "2024-10-07T07:15:05Z")

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typically, I track bubbles in volumes. Each bubble is a feature, described with a mesh, a label, and possibly other data. I would like to be able to have a file per bubble, and being able to create a collection of bubbles in a file by “just” managing a list of links. That way the data won’t be copied many time, and it could be very fast to rearrange the collection.  
Moreover, I would be able to manage additional data for bubble in a csv file, instead of copying the data for each node of the mesh (very expensive in term of memory).

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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 7, 2024, 7:16am UTC](https://discourse.vtk.org/t/one-file-to-merge-them-all/14671/4 "2024-10-07T07:16:43Z")

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Sounds like a typical composite dataset.

You can store it in a `.vtm`, a `.vtpdc` or a `.vtkhdf`, lots of possibilities 🙂

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### Author: ![Xtof](https://discourse.vtk.org/letter_avatar_proxy/v4/letter/x/c0e974/32.png) [@Xtof](https://discourse.vtk.org/u/Xtof)
#### Post date: [October 7, 2024, 7:27am UTC](https://discourse.vtk.org/t/one-file-to-merge-them-all/14671/5 "2024-10-07T07:27:47Z")

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OK, I found a previous post of yours : [About inlined multiblock and partitioned dataset XML data format](https://discourse.vtk.org/t/about-inlined-multiblock-and-partitioned-dataset-xml-data-format/10507)

RTFM… many thanks.  
I was stuck in the vtkLegacy format, I have to evolve !