# [Gmsh] subdividing an edge of a transfinite surface

David Colignon David.Colignon at ulg.ac.be
Tue May 11 15:49:37 CEST 2010

```Hi Colin,

it doesn't work because you don't have the same total number of mesh points on the two opposite sides (24 on one side
and 21 on the other)...

Regards,

Dave

--
David Colignon, Ph.D.
Collaborateur Logistique du F.R.S.-FNRS
CÉCI - Consortium des Équipements de Calcul Intensif
ACE - Applied & Computational Electromagnetics
Sart-Tilman B28
Université de Liège
4000 Liège - BELGIQUE
Tél: +32 (0)4 366 37 32
Fax: +32 (0)4 366 29 10
WWW:    http://hpc.montefiore.ulg.ac.be/

On 11/05/10 15:08, Dr Colin J. Cotter wrote:
> Dear Gmsh,
> 	I am running an aerodynamics problem which requires different boundary
> conditions to be applied on different segments of one side of a box. I
> tried to make a mesh using transfinite surface, but received the error
> that the surface cannot be meshed using the transfinite algorithm. Have
> I done something stupid, or is what I want not possible?
>
> I've included the .geo file to the bottom of this email.
>
> best wishes
> --Colin
>
> lc = 0.05;
> p1 = newp; Point(p1) = {0.0, 0.0, 0, lc};
> p2 = newp; Point(p2) = {0.5, 0.0, 0, lc};
> p3 = newp; Point(p3) = {1.0, 0.0, 0, lc};
> p4 = newp; Point(p4) = {1.5, 0.0, 0, lc};
> p5 = newp; Point(p5) = {2.0, 0.0, 0, lc};
> p6 = newp; Point(p6) = {2.0, 1.0, 0, lc};
> p7 = newp; Point(p7) = {0.0,1.0,0,lc};
>
> l1 = newl; Line(l1) = {p1, p2};
> l2 = newl; Line(l2) = {p2, p3};
> l3 = newl; Line(l3) = {p3, p4};
> l4 = newl; Line(l4) = {p4, p5};
> l5 = newl; Line(l5) = {p5, p6};
> l6 = newl; Line(l6) = {p6, p7};
> l7 = newl; Line(l7) = {p7, p1};
>
> Line Loop(1) = {l1,l2,l3,l4,l5,l6,l7};
> Plane Surface(1) = {1};
>
> Transfinite Line{l1} = 6;
> Transfinite Line{l2} = 6;
> Transfinite Line{l3} = 6;
> Transfinite Line{l4} = 6;
> Transfinite Line{l5} = 6;
> Transfinite Line{l6} = 24;
> Transfinite Line{l7} = 6;
>
> Transfinite Surface{1} = {p1,p5,p6,p7};
>
> Mesh.Smoothing = 100;
>
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```