[Gmsh] Conformal mesh on two parts

[Bernd Hahnebach]

I'm not familar in working with stl. I mostly work with step. The  
following has been working for very well, but for planar faces only !

in FreeCAD but possible in the CAD you prefere as well ...
- import the stl files --> convert the mesh into solids
- make a compound out ouf the solids
- export the compound to step

in GMSH
- open the compound step
- GMSH Tools --> Options --> Geometry --> General --> Cut and merge  
faces   (-string "Geometry.OCCConnectFaces = 1;")
- Mesh 3D
- ...

Bernd


Zitat von Krzysztof Bzowski <kbzowski at agh.edu.pl>:

> Hi,
> I have two parts, which need to be meshed. One part is located  
> inside another. To simplify the problem, imagine two cubes: one  
> inside another.
>
> http://i.stack.imgur.com/h87gD.png
>
> Geometries are stored in STL files. From CAD point of view, one file  
> contains an internal cube, another contains cube with a hole for an  
> internal cube. All dimensions fits (there are no intersections). My  
> task is to create a conformal tetrahedral mesh suitable for  
> mechanical FEM analysis - without duplicated nodes on shared faces.  
> Each element should contain information to which part it belongs.  
> File format does not matter but Abaqus is preferred.
>
> I decided to use gmsh, but I cannot mesh both parts together.
> I tried the following commands:
>
>  1. File -> Open Internal cube
>  2. Add volume to internal cube
>  3. File -> Merge External cube
>  4. Add volume to external cube
>
> This produces mesh but elements in internal cube are duplicated. It  
> looks like gmsh does not treat hole (in external cube) as a void. I  
> also tried to use Coherence in gmsh but it failed with error:
>
>> Error   : Self intersecting surface mesh, computing intersections  
>> (this could take a while)
>
>> Error   : Surface mesh is wrong, cannot do the 3D mesh
>
> I assume, that my geometries are fine:
>
>  - Internal cube: http://pastie.org/10673562
>  - External cube: http://pastie.org/10673564
>
> How to create such a mesh which satisfy my requirements?
>
> Best regards,
> Krzysztof
>
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