# \[Catalyst2|MeshBlueprint\] multiple meshes that share vertices

**URL:** https://discourse.paraview.org/t/catalyst2-meshblueprint-multiple-meshes-that-share-vertices/8971
**Category:** In Situ Support
**Created:** [February 15, 2022, 8:10am UTC](https://discourse.paraview.org/t/catalyst2-meshblueprint-multiple-meshes-that-share-vertices/8971 "2022-02-15T08:10:47Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![menno](https://discourse.paraview.org/user_avatar/discourse.paraview.org/menno/32/1127_2.png) [@menno](https://discourse.paraview.org/u/menno)
#### Post date: [February 15, 2022, 8:10am UTC](https://discourse.paraview.org/t/catalyst2-meshblueprint-multiple-meshes-that-share-vertices/8971/1 "2022-02-15T08:10:48Z")

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Is it possible to define multiple meshes/blocks that share the same vertices array? In our case we have a single list of vertices, from which we define the volume cells (as polyhedra) but also all the boundaries (as polygons). As far as I can see, this requires the `multi_mesh` protocol, with each block defined according to the Conduit MeshBlueprint protocol. That does seem to, however, require vertices (‘coords’) to be duplicatd in each block. Can that duplication be prevented?

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### Author: ![m.novak](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/m/ea666f/32.png) [@m.novak](https://discourse.paraview.org/u/m.novak)
#### Post date: [November 1, 2023, 5:09pm UTC](https://discourse.paraview.org/t/catalyst2-meshblueprint-multiple-meshes-that-share-vertices/8971/2 "2023-11-01T17:09:21Z")

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I do not think this can be avoided, at least I am yet to figure out how.  
Have you made any progress?