FEM Mesh Region

About the development of the FEM module/workbench.

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bernd
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Re: FEM Mesh Region

Postby bernd » Wed Sep 19, 2018 7:51 am

That means your FreeCAD is not compiled against vtk visualization Toolkit and thus you do not have all the visualization tools. You would need to install a FreeCAD binary which is compiled against vtk or compile FreeCAD yourself.

Bernd
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bernd
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Re: FEM Mesh Region

Postby bernd » Wed Sep 19, 2018 7:54 am

Workaround. You could use the FEM clipping tool to clip you geometry. Than you set on result_mesh the parameter show inner. With this you could have a look into the result even with the standard FreeCAD result object. See attaches a screen how it looks like for the StartModul 3D FEM example.

bernd

screen.jpg
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makkemal
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Re: FEM Mesh Region

Postby makkemal » Thu Jan 24, 2019 1:59 pm

I am getting a very interesting results with 1d meshes
The attached file has 3 lines each line has a meshregion equal to the length of the line.
But the middle line still gets more than one element. How do I force one element per line
meshregion_test.FCStd
(8.09 KiB) Downloaded 12 times


Thanks
Michael
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bernd
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Re: FEM Mesh Region

Postby bernd » Sat Jan 26, 2019 8:40 pm

makkemal wrote:
Thu Jan 24, 2019 1:59 pm
I am getting a very interesting results with 1d meshes
The attached file has 3 lines each line has a meshregion equal to the length of the line.
But the middle line still gets more than one element. How do I force one element per line
meshregion_test.FCStd
because you only can set the max elements size for a region.

To archive exact one element per line, just do not use any mesh region but set the min element size of the mesh greater than the longest line. File attached.

cheers bernd


meshregion_test_bernd1.FCStd
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bbatazai
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Re: FEM Mesh Region

Postby bbatazai » Fri Apr 12, 2019 9:20 am

Hello, I am sorry that I have open this topic again.
I am unable to reproduce the tutorial (https://www.freecadweb.org/wiki/FEM_She ... site_Block) since I upgraded to Freecad 0.18.

I cannot add the inner cube as mesh region even though I have the selection add on.

The steps I take are:

1) Create two Cubes, Use boolean fragments on them, change mode to CompSolid, use compound filter on them,
2) Select the compound filter, choose FEM Mesh from shape by Gmsh
3) Select the Mesh object, click 'add mesh region'. Add Outer cube as solid to mesh region
4) Select the Mesh object, click 'add mesh region'. In the graphical window put mouse over the solid, press S,E (Shortcut from selection add on), choose Faces of inner cube. Nothing happens.

What could I do?


Freecad Info:

OS: Debian GNU/Linux buster/sid
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.
Build type: Release
Python version: 2.7.16rc1
Qt version: 5.11.3
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedStates (en_US)

Edit:

I just saw the post in https://forum.freecadweb.org/viewtopic.php?f=18&t=34542 I will try whether this works. :?
Last edited by bbatazai on Fri Apr 12, 2019 9:30 am, edited 1 time in total.
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bernd
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Re: FEM Mesh Region

Postby bernd » Fri Apr 12, 2019 9:28 am

Have you read this topic: https://forum.freecadweb.org/viewtopic.php?f=18&t=34542 and tried the solutions proviede in the first two posts ? Where you run into the same problem?

bernd
bbatazai
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Re: FEM Mesh Region

Postby bbatazai » Fri Apr 12, 2019 10:15 am

I saw the post after posting :roll: .
Now I got a mesh with the distinct regions. For others having the problem, I did the following:

[ as before:
1) Create two Cubes, Use boolean fragments on them, change mode to CompSolid, use compound filter on them,
2) Select the compound filter, choose FEM Mesh from shape by Gmsh]

3) Select the Mesh object, click 'add mesh region'. Add the compound filter object by ticking 'solid' and adding on of the compound filter faces
4) Hide all objects but the solid of the inner cube
5) Select the Mesh object, click 'add mesh region'. Tick 'solid' and add the the inner cube.

Then i could get a mesh with gmsh.

Thank you again, Bernd!

Best
Baltasar


Edit: I have to make clear that this is the solution by bernd in the post https://forum.freecadweb.org/viewtopic. ... 42#p290156 . Be aware that you have to choose the compound filter for the outside region.
Last edited by bbatazai on Fri Apr 12, 2019 12:58 pm, edited 2 times in total.
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bernd
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Re: FEM Mesh Region

Postby bernd » Fri Apr 12, 2019 12:24 pm

Your work flow is a longer version of a post of mine from the other topic ...

bernd wrote:
Fri Mar 01, 2019 1:12 pm
You could make the BooleanFragment invisible and use the base solids instead. The geometry of them needs to be equal. But be carefull, if more than 2 Solids are involved the geometry of the base solid might not be equal with the solid you would like to select in BooldeanFragment.
bbatazai
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Re: FEM Mesh Region

Postby bbatazai » Fri Apr 12, 2019 12:57 pm

Sorry for not mentioning you. I edited the post accordingly.
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bernd
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Re: FEM Mesh Region

Postby bernd » Fri Apr 12, 2019 1:21 pm

bbatazai wrote:
Fri Apr 12, 2019 12:57 pm
Sorry for not mentioning you. I edited the post accordingly.
It is not about mention me it is about the following ...
bernd wrote:
Fri Apr 12, 2019 12:24 pm
But be carefull, if more than 2 Solids are involved the geometry of the base solid might not be equal with the solid you would like to select in BooldeanFragment.
If the solids go into each other this would not work! Thus we need to implemet some smarter selection like DeepSoic proposed, but I did not have the time to look it this so far.