[Gmsh] boolean partitioning

[Christophe Geuzaine]

Hi Andrew,

Yes, I think that a combination of BooleanFragments and embedded surfaces should do what you want:

SetFactory("OpenCASCADE");
Block(1) = {-0, 0, 0, 1, 1, 1};
// intersecting:
Rectangle(7) = {0.4, 0.7, 0.2, 0.3, 0.3, 0};
Rectangle(8) = {-0.2, 0.3, 0.5, 0.3, 0.3, 0};
Rectangle(9) = {0.8, -0.2, 0.5, 0.3, 0.3, 0};
BooleanFragments{ Volume{1}; Delete; }{ Surface{7:9}; Delete; }
// fully inside
Rectangle(30) = {0.3, 0.3, 0.5, 0.3, 0.3, 0};
Surface {30} In Volume{1};

Christophe




> On 2 May 2017, at 19:57, andrew <armitatz at gmail.com> wrote:
> 
> 
> hi,
> 
> In Salome which uses the opencascade model there is a Boolean operation called partition. With this you can create a solid from two others but with a shared face. A usage of that is the creation of meshes with internal walls in it with zero thickness aka 'baffles'. Is there a procedure in gmsh that can give the same results given that it has implemented the same opencascade model? Obviously there is a way to have such results if you give the precise geometry but sometimes it is very difficult to cut geometries and it is easier if gmsh could do that.
> 
> Attached is an image of a mesh with internal baffles created with partitioning and the geometry that created it. I would prefer t if gmsh could do the meshing but I haven't found a way to load the geometry to gmsh from Salome.
> 
> kind regards
> 
> Andrew
> 
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-- 
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science 
http://www.montefiore.ulg.ac.be/~geuzaine

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