# [Gmsh] Structured 2D mesh for structure more than 8 corners !

DILASSER Guillaume Guillaume.DILASSER at cea.fr
Thu Feb 16 09:13:13 CET 2017

```Hi,

If I am not mistaken, the transfinite algorithm only handles 4-sided surfaces so you will probably need to split your surface into rectangular blocks for it to work. In that case, you are probably better using extrusions. See the attached example and let me know if it helped.

Guillaume DILASSER
Doctorant SACM / LEAS
CEA - Centre de Saclay - Bât.123 - PC 319c
91191 Gif sur Yvette Cedex - France -

guillaume.dilasser at cea.fr<mailto:guillaume.dilasser at cea.fr>

De : gmsh [mailto:gmsh-bounces at ace20.montefiore.ulg.ac.be] De la part de Gladiator Gladiator
Envoyé : mercredi 15 février 2017 14:41
À : gmsh at onelab.info
Objet : [Gmsh] Structured 2D mesh for structure more than 8 corners !

Dear all,

I am trying to make a structured mesh for following algorithm, but I could not make it.
And my mesh is still unstructured !
Would you please let me know where I made a mistake ?
Many thanks,

this is my algorithm:
//**********************************
Point(1) = {0, 0, 0, 1.0};
Point(2) = {10, 0, 0, 1.0};
Point(3) = {10, 4, 0, 1.0};
Point(4) = {5, 4, 0, 1.0};
Point(5) = {5, 5, 0, 1.0};
Point(6) = {10, 5, 0, 1.0};
Point(7) = {10, 10, 0, 1.0};
Point(8) = {0, 10, 0, 1.0};

Line(1) = {1, 2};
Line(2) = {2, 3};
Line(3) = {3, 4};
Line(4) = {4, 5};
Line(5) = {5, 6};
Line(6) = {6, 7};
Line(7) = {7, 8};
Line(8) = {8, 1};

Line Loop(9) = {7, 8, 1, 2, 3, 4, 5, 6};

Plane Surface(10) = {9};
Physical Surface(11) = {10};

Transfinite Line {2}=5;
Transfinite Line {6}=6;
Transfinite Line {8}= 11;
Transfinite Line {7}= 11;
Transfinite Line {1}= 11;
Transfinite Line {3,5} =6;
Transfinite Line {4} = 2;

Transfinite Surface {10}={5,6,7,8,1,2,3,4};
Recombine Surface {10};

Again, thank you all,
Best,

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