# [Gmsh] consistent structured mesh

Christophe Geuzaine cgeuzaine at ulg.ac.be
Sat Mar 18 09:58:34 CET 2017

```> On 16 Mar 2017, at 18:59, Boehm, Christian Hermann Kurt <christian.boehm at hm.edu> wrote:
>
> Dear gmsh-community,
>
> i really need your help because otherwise i will despair. I use gmsh for my masterthesis in computational engineering for geometry modeling and finite-element meshing.
> My problem is, that i can't create a consistent structured mesh of e.g. a T-section. Here is a little example:
>
> Point(1)={0,0,0};
> Point(2)={10,0,0};
> Point(3)={10,10,0};
> Point(4)={0,10,0};
> Point(5)={2.5,6,0};
> Point(6)={7.5,6,0};
> Point(7)={7.5,6,10};
> Point(8)={2.5,6,10};
>
> Line(1)={1,2};
> Line(2)={2,3};
> Line(3)={3,4};
> Line(4)={4,1};
> Line(5)={5,6};
> Line(6)={6,7};
> Line(7)={7,8};
> Line(8)={8,5};
>
> Line Loop(1)={1,2,3,4};
> Line Loop(2)={5,6,7,8};
>
> Plane Surface(1)={1};
> Plane Surface(2)={2};
>
> Line{5} In Surface{1};
> Transfinite Surface{1:2};
> Recombine Surface{1:2};
>
> Is it possible to create a structured mesh, so that there will be nodes created on line(5) which is in surface(2). This is necessary for me, because the meshes of the two plates have to be consistent.
> Or is there any other way to create a consistent structured mesh for this example.
> I know that i can split the "ground-plate" by defining more lines and planes to get a structured mesh, but this is not expedient.

but it's the way to go... that's the annoying thing with structured grids ;-)

(You could actually do it without, but I don't recommend it: if you set the number of subdivisions so that the mesh vertices match at the interface, you can mesh the (unconnected) surfaces, save the mesh, reload it, and apply "Coherence Mesh" on the result to fuse duplicate vertices/elements. But this is clearly a hack.)

Christophe

> Thank you very much for your help.
>
> Kind regards,
> Christian
> Munich University of Applied Sciences
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--
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science
http://www.montefiore.ulg.ac.be/~geuzaine

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