Example of an Hex mesh with GMSH

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bernd
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Re: Example of an Hex mesh with GMSH

Post by bernd »

What happens if you would use different values for the symmetric edges ?
sodelo
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Re: Example of an Hex mesh with GMSH

Post by sodelo »

This is what I am exploring.
I base my tests on my old example I prepared years ago. There may be novelties. I am having a look at the documentation.
test2.png
test2.png (18.41 KiB) Viewed 2188 times
2 volumes do not have the same number of elements on the left and on the right. Resulting mesh is a free quad-dominated mesh, which is a nice possibility for transitions of density. Not sure the result is correct since there are error messages.

Edit: This mesh is not correct. I need to work on this.
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makkemal
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Re: Example of an Hex mesh with GMSH

Post by makkemal »

So I finally got to redoing the demo video from last week and when I created the mesh with GMSH this is what I got.
Is some of this in the master already ?
mesh.png
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File
funny_mesh.fcstd
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bernd
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Re: Example of an Hex mesh with GMSH

Post by bernd »

No not yet in master, you need to edit the geo file which is created from FreeCAD or be patient for a few days ...
sodelo
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Re: Example of an Hex mesh with GMSH

Post by sodelo »

I do not find any working solution so far to have different element numbers on 2 sides.
I will try to ask for help to the gmsh mailing list. Until then, do not count on it.
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Re: Example of an Hex mesh with GMSH

Post by sodelo »

Double-sided progression to create surface layer.

Code: Select all

Merge "cube.brep";
Transfinite Line "*" = 20 Using Bump 0.05;
Transfinite Surface "*";
Recombine Surface "*";
Transfinite Volume "*";
layer.png
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sodelo
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Re: Example of an Hex mesh with GMSH

Post by sodelo »

At least we stil have the good old partitionning mehod to change the mesh density ...
cube2.png
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bernd
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Re: Example of an Hex mesh with GMSH

Post by bernd »

sodelo wrote:At least we stil have the good old partitionning mehod to change the mesh density ...
how does the geo for this looks like?
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Re: Example of an Hex mesh with GMSH

Post by sodelo »

The GEO is like the previous ones.
The partition has to be done in Freecad.

Since the GMSH capabilities for Hex are somewhat limited (compared to commercial softs), we will have to do a lot of preparation on the model (volume subdivision and numbering all the edges). It would be nice to get:
- a one click solution for subdivision (instead of extrusion+booleanoperation + compound filter),
- a detection of linked edges (edges which have to get the same number of elements). This one is much more difficult :?
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Re: Example of an Hex mesh with GMSH

Post by HoWil »

sodelo wrote:It would be nice to get:
- a one click solution for subdivision (instead of extrusion+booleanoperation + compound filter),
- a detection of linked edges (edges which have to get the same number of elements). This one is much more difficult :?
This is what I was thinking of. Maybe one can select the top or bottom face or an extruded object and the depth info is extracted from the edges inbetween or from the extruded object.
BR
Howil
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