# Paraview/VTK crushes when opening triangulated surface
**URL:** https://discourse.paraview.org/t/paraview-vtk-crushes-when-opening-triangulated-surface/7330
**Category:** ParaView Support
**Tags:** python, vtk
**Created:** [May 31, 2021, 1:53pm UTC](https://discourse.paraview.org/t/paraview-vtk-crushes-when-opening-triangulated-surface/7330 "2021-05-31T13:53:56Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@IgnacioV](https://discourse.paraview.org/u/IgnacioV)
#### Post date: [May 31, 2021, 1:53pm UTC](https://discourse.paraview.org/t/paraview-vtk-crushes-when-opening-triangulated-surface/7330/1 "2021-05-31T13:53:56Z")
OS: Windows 10 64b
ParaView version: 5.9.0
Where you obtained ParaView: binary download link
GPU: Nvidia 1660S
Hello, I’m trying to open a custom triangulated surface I made using a mine pit elevation contour lines and some information about the materials in the surface, I made one file per type of material (4). The resulting vtp files make paraview/VTK crush instantly when opened. I can open them in the vtp web viewer: [vtk.js](https://kitware.github.io/vtk-js/examples/GeometryViewer.html) and they look fine. I guess it might be related to some geometry problem in my calculations for the vertices, but I don’t know if there is a way to get a crush log without building paraview on my own.
The files are in the following link: [https://drive.google.com/open?id=1hqVUqbZaAEJkJuWMTsOaoq8wPJ9WBwrI](https://drive.google.com/open?id=1hqVUqbZaAEJkJuWMTsOaoq8wPJ9WBwrI)
I hope someone could enlighten me on how to debug/solve my problem.
I can post the python code to make the files if needed.
Cheers,
Ignacio V.
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [May 31, 2021, 3:04pm UTC](https://discourse.paraview.org/t/paraview-vtk-crushes-when-opening-triangulated-surface/7330/2 "2021-05-31T15:04:24Z")
Your file is malformed (but paraview should error out, not crash).
I suspect that some cells contains references to non-existent points.
Please write your file in ASCII mode instead of Appended so we can understand what is wrong with it.
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### Author:  [@IgnacioV](https://discourse.paraview.org/u/IgnacioV)
#### Post date: [May 31, 2021, 4:59pm UTC](https://discourse.paraview.org/t/paraview-vtk-crushes-when-opening-triangulated-surface/7330/3 "2021-05-31T16:59:42Z")
Ah! Thanks a lot, that was it, how do you debug a file to identify the problem? There were some NAN values that were outside the topographic data and I was skipping them when adding the point data and then I was assigning the vertices for all triangles, including those discarded previously. Now I’ve changed that in my code and everything goes well.
Thanks again!
Cheers,
Ignacio V.
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### Author:  [@mwestphal](https://discourse.paraview.org/u/mwestphal)
#### Post date: [May 31, 2021, 6:59pm UTC](https://discourse.paraview.org/t/paraview-vtk-crushes-when-opening-triangulated-surface/7330/4 "2021-05-31T18:59:23Z")
> [@IgnacioV](#):
>
> how do you debug a file to identify the problem?
I just reproduce your issue with gdb and valgrind to understand the issue.
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### Author:  [@IgnacioV](https://discourse.paraview.org/u/IgnacioV)
#### Post date: [June 1, 2021, 12:34pm UTC](https://discourse.paraview.org/t/paraview-vtk-crushes-when-opening-triangulated-surface/7330/5 "2021-06-01T12:34:23Z")
I don’t have any experience on those tools, but thanks anyway.
Salutation depuis Grenoble.
Ignacio V.