# "Piece Distribution" When loading \*.vtm Block vs. Interleave
**URL:** https://discourse.paraview.org/t/piece-distribution-when-loading-vtm-block-vs-interleave/3980
**Category:** ParaView Support
**Created:** [April 6, 2020, 8:20pm UTC](https://discourse.paraview.org/t/piece-distribution-when-loading-vtm-block-vs-interleave/3980 "2020-04-06T20:20:28Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@patchett2002](https://discourse.paraview.org/u/patchett2002)
#### Post date: [April 6, 2020, 8:20pm UTC](https://discourse.paraview.org/t/piece-distribution-when-loading-vtm-block-vs-interleave/3980/1 "2020-04-06T20:20:28Z")
When loading a VTK Multiblock (\*.vtm) I have the option of a dropdown box that lets me to choose Block or Interleave. What exactly does this do?
If each block is composed of multiple pieces, does it distribute the pieces when I choose Interleave? that is, distribute by piece then by block?
If I choose Block, does it distribute by Block first, then by pieces if they exist?
“Piece Distribution” does not seem to occur in ParaViewGuide-5.8.0.
Mouseover help just says “Control how datasets are loaded in parallel.”
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [April 7, 2020, 3:22am UTC](https://discourse.paraview.org/t/piece-distribution-when-loading-vtm-block-vs-interleave/3980/2 "2020-04-07T03:22:13Z")
[https://vtk.org/doc/nightly/html/classvtkXMLCompositeDataReader.html#adb77e26776430c7aebbcc3fd26f3e2da](https://vtk.org/doc/nightly/html/classvtkXMLCompositeDataReader.html#adb77e26776430c7aebbcc3fd26f3e2da)
```
Let *X* be the rank of a specific reader, and *N* be the number of reader, then:
* `Block` Each processor is assigned a contiguous block of files, [ *X* * *N* , ( *X* + 1) * *N* ).
* `Interleave` The files are interleaved across readers, *i* * *N* + *X* .
```
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### Author:  [@utkarsh.ayachit](https://discourse.paraview.org/u/utkarsh.ayachit)
#### Post date: [April 7, 2020, 11:21am UTC](https://discourse.paraview.org/t/piece-distribution-when-loading-vtm-block-vs-interleave/3980/3 "2020-04-07T11:21:03Z")
> [@patchett2002](#):
>
> If I choose Block, does it distribute by Block first, then by pieces if they exist?
It doesn’t make any distinction between blocks and pieces. All leaf nodes in the multiblock dataset hierarchy are treated the same.