# [Gmsh] Re : Are surfaces connected in layered sphere

Durufle marc marc_durufle at yahoo.fr
Wed Nov 23 12:22:04 CET 2005

```I have a geo file, which does a dielectric sphere with
an outside layer. I don't understand well your
question, but if you try this geo file :

lc = 0.4;
a = 2.0;
b = 3.0;

// Dielectric Sphere
Point(1) = {0,0,0,lc};
Point(2) = {0,-a,0,lc};
Point(3) = {-a,0,0,lc};
Point(4) = {0,a,0,lc};
Point(5) = {0,-b,0,lc};
Point(6) = {-b,0,0,lc};
Point(7) = {0,b,0,lc};

Line(1) = {2,5};
Circle(2) = {5,1,6};
Circle(3) = {6,1,7};
Line(4) = {7,4};
Circle(5) = {4,1,3};
Circle(6) = {3,1,2};
Line(7) = {2,4};

Line Loop(1) = {1,2,3,4,5,6};
Line Loop(2) = {5,6,7};
Plane Surface(1) = {1};
Plane Surface(2) = {2};

// extrusion outside sphere layer
Extrude Surface {1, {0.0,1.0,0.0}, {0.0,0.0,0.0},
2*Pi/3};
Extrude Surface {29, {0.0,1.0,0.0}, {0.0,0.0,0.0},
2*Pi/3};
Extrude Surface {51, {0.0,1.0,0.0}, {0.0,0.0,0.0},
2*Pi/3};

// extrusion inside sphere
Extrude Surface {2, {0.0,1.0,0.0}, {0.0,0.0,0.0},
2*Pi/3};
Extrude Surface {84, {0.0,1.0,0.0}, {0.0,0.0,0.0},
2*Pi/3};
Extrude Surface {96, {0.0,1.0,0.0}, {0.0,0.0,0.0},
2*Pi/3};

Physical Surface(1) = {25,28,47,50,69,72};
Physical Surface(3) = {18,21,40,43,62,65};

Physical Volume(1) = {1,2,3};
Physical Volume(2) = {4,5,6};

You will have the tetrahedras and also triangles for
the two spheres.

Your file is OK, but you don't create any physical
surface, it is better if you want to get the surfacic
meshes of the two spheres. Sure the tetrahedras
connect the two spheres, and the mesh is conform.

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