# VTK-9.0.3-1 is asserting with a simple cube FEM in FreeCAD

**URL:** https://discourse.vtk.org/t/vtk-9-0-3-1-is-asserting-with-a-simple-cube-fem-in-freecad/6749
**Category:** Support
**Created:** [October 1, 2021, 6:30pm UTC](https://discourse.vtk.org/t/vtk-9-0-3-1-is-asserting-with-a-simple-cube-fem-in-freecad/6749 "2021-10-01T18:30:36Z")
**Posts on this page:** 5
**Page:** 2

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### Author: ![linux\_guy](https://discourse.vtk.org/user_avatar/discourse.vtk.org/linux_guy/32/4029_2.png) [@linux\_guy](https://discourse.vtk.org/u/linux_guy)
#### Post date: [October 5, 2021, 9:13pm UTC](https://discourse.vtk.org/t/vtk-9-0-3-1-is-asserting-with-a-simple-cube-fem-in-freecad/6749/22 "2021-10-05T21:13:31Z")

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I’ve got a bunch of cmake config errors from missing libraries that I’ll have to track down. Is it worth it for me to build vtk-8.0.2 and test with it ?

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### Author: ![linux\_guy](https://discourse.vtk.org/user_avatar/discourse.vtk.org/linux_guy/32/4029_2.png) [@linux\_guy](https://discourse.vtk.org/u/linux_guy)
#### Post date: [October 5, 2021, 9:32pm UTC](https://discourse.vtk.org/t/vtk-9-0-3-1-is-asserting-with-a-simple-cube-fem-in-freecad/6749/23 "2021-10-05T21:32:39Z")

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I’ll need help figuring some of these out. For example \_\_int64. And the pthread error.

See attached.  
[CMakeError.log](https://discourse.vtk.org/uploads/short-url/aCZwHb8vFYYMk2hYLs8Fk58Tglm.log) (57.1 KB)

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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 6, 2021, 7:27am UTC](https://discourse.vtk.org/t/vtk-9-0-3-1-is-asserting-with-a-simple-cube-fem-in-freecad/6749/24 "2021-10-06T07:27:52Z")

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> [@linux\_guy](#):
>
> Is it worth it for me to build vtk-8.0.2 and test with it ?

Probably not, the changes between VTK8 and VTK9 are too big.

> Does anything about this look suspicious to you ?

It just means `SMDS_Mesh::_meshList[myMeshId]->getGrid();` does not contain the expected unstructured grid, you will have to find out how it is created. Also you may want to check how many points does it actually contains ? 0 or 1 ?

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### Author: ![linux\_guy](https://discourse.vtk.org/user_avatar/discourse.vtk.org/linux_guy/32/4029_2.png) [@linux\_guy](https://discourse.vtk.org/u/linux_guy)
#### Post date: [October 6, 2021, 4:42pm UTC](https://discourse.vtk.org/t/vtk-9-0-3-1-is-asserting-with-a-simple-cube-fem-in-freecad/6749/25 "2021-10-06T16:42:13Z")

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So why does vtk-7,8 handle this without a problem and vtk-9 returns the wrong number ? There is a bug in vtk-9.

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### Author: ![linux\_guy](https://discourse.vtk.org/user_avatar/discourse.vtk.org/linux_guy/32/4029_2.png) [@linux\_guy](https://discourse.vtk.org/u/linux_guy)
#### Post date: [October 7, 2021, 12:11am UTC](https://discourse.vtk.org/t/vtk-9-0-3-1-is-asserting-with-a-simple-cube-fem-in-freecad/6749/26 "2021-10-07T00:11:48Z")

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The cube can be meshed with FreeCAD 0.19-2 run via appimage.

OS: Fedora 34 (Workstation Edition) (KDE/plasmax11)  
Word size of OS: 64-bit  
Word size of FreeCAD: 64-bit  
Version: 0.19.24291 (Git) AppImage  
Build type: Release  
Branch: (HEAD detached at 0.19.2)  
Hash: 7b5e18a0759de778b74d3a5c17eba9cb815035ac  
Python version: 3.8.8  
Qt version: 5.12.9  
Coin version: 4.0.0  
OCC version: 7.4.0  
Locale: English/United States (en\_US)

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