# [Gmsh] Meshing volumes with multiple inclusions

Philipp Metsch philipp.metsch at tu-dresden.de
Wed Sep 27 14:22:44 CEST 2017

Anybody any ideas?
--
Dipl.-Ing. Philipp Metsch

Technische Universität Dresden
Fakultät Maschinenwesen
Institut für Festkörpermechanik
Professur für Numerische und Experimentelle Festkörpermechanik
01062 Dresden
Tel.: +49 (351) 463-33284
Fax: +49 (351) 463-37061
E-Mail: Philipp.Metsch at tu-dresden.de

Am Freitag, den 18.08.2017, 16:37 +0200 schrieb Philipp Metsch:
> Hi everybody,
>
> I have a problem with the mesh generation of a domain which
> incorporates several inclusions that are allowed to intersect the
> boundaries. The basic idea is to generate a periodic representative
> volume element by using Boolean operations in Gmsh. So far, the
> geometry generation seems to work quite well but when I try to mesh
> the resulting geometry with Gmsh, I always get the error that there
> are intersecting surfaces in the surface mesh. For this reason, the
> 3D mesh is not completed. What do I do wrong? Does anybody have any
> ideas?
>
> My .geo-file looks as follows (here only a simplified version with a
> few inclusions):
>
> // Activate OpenCASCADE geometry module
>
> // Number of inclusions
> nInc=14;
>
> // Geometrical tolerance
> tol=Geometry.Tolerance;
>
> // Mesh options
> h=0.5;
> p=1;
>
> // Cuboid
> Box(1) = {0, 0, 0, 10, 10, 10};
>
> // Inclusions
> Sphere(2) = {7.9403,3.8106,4.0937,2.5};
> Sphere(3) = {-2.0597,3.8106,4.0937,2.5};
> Sphere(4) = {3.1291,8.6325,8.5502,2.5};
> Sphere(5) = {3.1291,-1.3675,8.5502,2.5};
> Sphere(6) = {3.1291,8.6325,-1.4498,2.5};
> Sphere(7) = {3.1291,-1.3675,-1.4498,2.5};
> Sphere(8) = {8.9159,8.8189,5.2511,2.5};
> Sphere(9) = {-1.0841,8.8189,5.2511,2.5};
> Sphere(10) = {8.9159,-1.1811,5.2511,2.5};
> Sphere(11) = {-1.0841,-1.1811,5.2511,2.5};
> Sphere(12) = {9.9252,4.1353,9.0195,2.5};
> Sphere(13) = {-0.074811,4.1353,9.0195,2.5};
> Sphere(14) = {9.9252,4.1353,-0.98047,2.5};
> Sphere(15) = {-0.074811,4.1353,-0.98047,2.5};
>
> // Boolean Operations
> Inclusions[]=BooleanIntersection{ Volume{1}; }{ Volume{2:nInc+1};
> Delete;};
> Matrix[]=BooleanDifference{ Volume{1}; Delete; }{
> Volume{Inclusions[]}; };
>
>
> // General Meshing Options
> AllSurfs[] = Unique(Abs(Boundary{ Volume{Matrix[]};
> Volume{Inclusions[]}; }));
> AllLines[] = Unique(Abs(Boundary{ Surface{AllSurfs[]}; }));
> AllPoints[] = Unique(Abs(Boundary{ Line{AllLines[]}; }));
> Characteristic Length { AllPoints[] } = h;
> Mesh.ElementOrder = p;
>
> Mesh 3;
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