[Gmsh] Format Mesh and Boundary Conditions

[Adam Larat]

Hello you all,
I hope I am not speaking about a subject that has already been discussed.



Here is a small example :

"gmsh-2.4.2 -2 -o Carre.mesh -format mesh Carre.geo"
and obtained the mesh described in Carre.mesh.
I got 12 edges :

Edges
12
1 2 1
2 3 2
3 4 3
4 1 4
5 9 6
9 6 6
6 10 7
10 7 7
7 11 8
11 8 8
8 12 9
12 5 9



Physical Line(1) = {1,2,3,4};
Physical Line(2) = {6,7,8,9};





Thanks,

Adam


// Variables
size_carre = 10.0;
char_carre = size_carre;
size_hole = 1.0;
char_hole = size_hole;

// Points
Point(1) = { size_carre,-size_carre,0,char_carre};
Point(2) = { size_carre, size_carre,0,char_carre};
Point(3) = {-size_carre, size_carre,0,char_carre};
Point(4) = {-size_carre,-size_carre,0,char_carre};

Point(5) = { size_hole,        0.0,0,char_hole};
Point(6) = {        0.0, size_hole,0,char_hole};
Point(7) = {-size_hole,        0.0,0,char_hole};
Point(8) = {        0.0,-size_hole,0,char_hole};

Point(9) = {        0.0,       0.0,0,char_hole};

// Lines and Line Loops
Line(1) = {1,2};
Line(2) = {2,3};
Line(3) = {3,4};
Line(4) = {4,1};
Line Loop(5) = {1,2,3,4};

Circle(6) = {5,9,6};
Circle(7) = {6,9,7};
Circle(8) = {7,9,8};
Circle(9) = {8,9,5};
Line Loop(10) = {6,7,8,9};

Physical Line(1) = {1,2,3,4};
Physical Line(2) = {6,7,8,9};

// Surface
Plane Surface(1) = {5,10};
Physical Surface(0) = {1};

I am using the "*.mesh" format for my meshes because I find this format really easy to read. I have noticed that in this format the boundary edges are not tagged by the number of the physical entity they belong to, but by the number of the line they belong to. I have generated a very awful mesh with the Carre.geo file attached by command that are tagged by the line they belong to and not by the physical tag I gave to those lines : The same for the triangles that are tagged by the number of the surface they belong to (1) and not by the physical tag of this surface (0). Is there any reason for that ? Maybe there exists a option that allows me to take those physical tags into account ?

Carre.mesh
Description: Mesh model

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