# [Gmsh] Structured mesh

paul.carrico at free.fr paul.carrico at free.fr
Thu Apr 24 14:07:05 CEST 2003

```Hi,

I would like to make a 3D structured mesh with a simplest object : a cube !
Following the t6.geo tutorial file, I realised :

1- a square
2- a surface
3- an extrusion of the surface
4- a volume

(basically ! ! !)

5- Transfinite the lines
6- Transfinite the surfaces (and click onto vertices)
7- Transfinite the volume (same number as item 4 .. and click onto vertices)
8- Then Recombine surface

(
see the result below) !

I only have quadrangle onto the surface but not any hexahedra
what I’m doing
wrong ?
It’s probably a very basic question but I don’t understand

Just a remark : I’m learning both GMSH and Code ASTER (FEA software)
both GPL
softwares ! the relationship between the 2 softwares shows that GMSH becomes
more and more powerfull ! Thank to the GMSH group for it !

PC

#################
#    File cube.geo     #
#################
Point(1) = {0,0,0,0.1};
Point(2) = {1,0,0,0.1};
Point(3) = {1,1,0,0.1};
Point(4) = {0,1,0,0.1};
Line(1) = {2,3};
Line(2) = {3,4};
Line(3) = {4,1};
Line(4) = {1,2};
Line Loop(5) = {2,3,4,1};
Plane Surface(6) = {5};
Extrude Surface {6, {0,0,1}};
Surface Loop(29) = {15,6,19,23,27,28};
Volume(30) = {29};

Transfinite Line {9,10,11,8,13,18,22,4,1,3,2,14} = 10;
Transfinite Surface {19} = {1,10,6,4};
Transfinite Surface {23} = {14,2,1,10};
Transfinite Surface {27} = {14,2,3,5};
Transfinite Surface {15} = {3,5,6,4};
Transfinite Surface {28} = {6,5,14,10};
Transfinite Surface {6} = {2,3,4,1};
Transfinite Volume{30} = {4,6,3,5,1,2,10,14};
Recombine Surface {15,28,19,6,27,23};
Physical Point(51) = {6,10,1,14,2,5,3,4};
Physical Line(52) = {13,8,14,2,3,9,18,10,4,11,1,22};
Physical Surface(31) = {27,6,19,28,15,23};
Physical Volume(50) = {30};

```