# (CGNS) Is it possible to load boundary patches from a CGNS file?

**URL:** https://discourse.paraview.org/t/cgns-is-it-possible-to-load-boundary-patches-from-a-cgns-file/8119
**Category:** ParaView Support
**Created:** [October 3, 2021, 7:07pm UTC](https://discourse.paraview.org/t/cgns-is-it-possible-to-load-boundary-patches-from-a-cgns-file/8119 "2021-10-03T19:07:50Z")
**Posts on this page:** 1
**Showing post:** 1

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### Author: ![SadBoySquad](https://discourse.paraview.org/user_avatar/discourse.paraview.org/sadboysquad/32/11775_2.png) [@SadBoySquad](https://discourse.paraview.org/u/SadBoySquad)
#### Post date: [October 3, 2021, 7:07pm UTC](https://discourse.paraview.org/t/cgns-is-it-possible-to-load-boundary-patches-from-a-cgns-file/8119/1 "2021-10-03T19:07:50Z")

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Greetings to all people of this forum!

For the past few days I have been searching for a way to display flow properties on boundary patches defined in the CGNS file, unfortunately to no avail.

I found a relevant thread, but has zero responses:

> [@Viewing boundary patch in CGNS files](https://discourse.paraview.org/t/viewing-boundary-patch-in-cgns-files/7732):
>
> Hello, I have a CGNS file divided into 200 zones. Some of these zones have additional boundary patches, including possibly an “AIRFOIL” boundary patch. I only want to display the airfoil. In Ensight, this is easy. I load my file, I hide all parts, then search AIRFOIL parts only, select, and show. In Paraview, I load up my file, and look at properties. “Hierarchy”, “Grids”, and “Patches” only have the 200 zones listed. The Multiblock Inspector lets me see which zones have patches, but not what…

I also found a plugin that was written for older ParaView versions (it lists 4.3.1 on Git log), but does not work for current versions (I am on 5.9).

> **[GitHub - MicK7/CGNSReader\_ParaView\_Plugin: small ParaView plugin to read cgns...](https://github.com/MicK7/CGNSReader_ParaView_Plugin)**
>
> small ParaView plugin to read cgns files. Contribute to MicK7/CGNSReader\_ParaView\_Plugin development by creating an account on GitHub.

I think the plugin loads correctly, since I am able to have the new “Load Boundary Elements (Unstructured Grid)” option.  
However, I am not able to get the relevant info in the Multi-block inspector; inside the doc/ directory on the plugin Git repo there is a picture that shows the boundary patches loaded on Paraview. My “patches” family has 0 entries instead.

In addition, I think when multiple element sections are present, ParaView displays only the first.  
Maybe this has something to do with not being able to view the relevant boundary patches?

The cgns file used in the plugin examples is an example cgns file from the cgns site:  
[https://cgns.github.io/CGNSFiles.html](https://cgns.github.io/CGNSFiles.html)

It is the yf17 file from the unstructured examples.

I tried to read the plugin and try to find what’s wrong with it and maybe fix it, but unfortunately I am not experienced with ParaView plugins.

A last note: When a cgns file with ZoneBC info is read, I think ParaView load boundary patches since it displays warnings if an unknown BC type is read. So I think it does something with the info at least.

Is there anything I can try?

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