# [Gmsh] Having trouble to mesh muilti-domain geometries

Wesley Ranger metorm at outlook.com
Fri Nov 3 13:23:32 CET 2017

```Hi guys

I am having trouble meshing a geometry composed of 3 kinds of materials. Let's call them material A, B and C.

The 3 material in the geometry has 2 interfaces. I defined several physical surfaces and 3 physical domains.

Weird things happened then. In the resulting mesh, the vertices on A/B interface are well aligned, i.e. each vertex on A/B interface and belongs to A mesh has an identical copy in B mesh. They have the same coordinates, so I can connect them in solving stage.

However, the vertices on B/C are not well aligned. A vertex belongs to C mesh may be located in the middle of a facet which belongs to B mesh.

It is hard to describe using words, so I posted a question here:

https://stackoverflow.com/questions/47095493/any-way-to-make-gmsh-to-use-the-same-vertex-set-on-both-sides-of-a-material-boun
[https://cdn.sstatic.net/Sites/stackoverflow/img/apple-touch-icon@2.png?v=73d79a89bded]<https://stackoverflow.com/questions/47095493/any-way-to-make-gmsh-to-use-the-same-vertex-set-on-both-sides-of-a-material-boun>

Any way to make gmsh to use the same vertex set on both sides of a material boundary?<https://stackoverflow.com/questions/47095493/any-way-to-make-gmsh-to-use-the-same-vertex-set-on-both-sides-of-a-material-boun>
I am trying to mesh a complex geometry composed of 3 kinds of materials, like below: The geometry is imported from a *.stp file. I defined several physical surfaces and 3 physical domains in the ...
stackoverflow.com

Anyone, please give me some suggestions to handle this. Thank you!
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