[Gmsh] structured and unstructured meshes bug

[Michel Aubourg]

Hi Christophe,

Thank you very much for this answer.

I did't find that in the documentation (the HTML one build from sources 
distribution) where we can read that the surfaces are meshed before the 
volumes and that the so generated triangles are forced to be faces of the 
tetrahedra created later.
I understood that the mesh of an internal surface was uniquely defined, which 
is not the case; I suggest to up-to-date this documentation to avoid 
disapointment for future users.

In another way I join a very short file for which the use of "isotropic" gives 
of course bad mesh and "netgen" crashes; what is wrong ?

I used gmsh 1.60.1 and 1.64.1 both compiled alternatively with gcc-3.4.3, 
gcc-3.3.6 and gcc-4.0.1.

Best,

Michel

Le Mercredi 22 Mars 2006 02:11, vous avez écrit :
> Michel Aubourg wrote:
> > Re-bonjour,
> >
> > Avec le fichier joint cela ira mieux.
>
> Hi Michel - Unfortunately, that's inherent to the Delaunay technique as
> implemented in the default "isotropic" algorithm. You can use the
> combined Delaunay+advancing front technique from the "netgen" algorithm
> to fix this. (Add e.g. "Mesh.Algorithm3D = 4;" at the beginning of your
> file; beware that your volume boundary has to be defined with exterior
> pointing normals when using this algorithm.)
>
> Best,
>
> Christophe
>
-------------- next part --------------
a = 10;
m = 10;

Point(1) = {0,0,0,m};

Extrude {a,0,0} {
  Point{1};
  Layers {{1},{1.0}};
}
Extrude {0,a,0} {
  Line{1};
  Layers {{1},{1.0}};
}

bottom[] =
Extrude {0,0,-a} {
  Surface{5};
  Layers {{1},{1.0}};
}
;

top[] =
Extrude {0,0,a} {
  Surface{5};
}
;

Physical Surface(50) = {27};
Physical Surface(51) = {5};
Physical Surface(52) = {49};
Physical Surface(53) = {14,36};
Physical Surface(54) = {22,44};
Physical Surface(55) = {26,48};
Physical Surface(56) = {18,40};

v1 = newreg;
Physical Volume(v1) = {bottom[]};
v2 = newreg;
Physical Volume(v2) = {top[]};