[Gmsh] gmsh-2.5.1: 2D unstructured mixed triangle-quadrangle problem (recombine+angle)

Pierre Saramito Pierre.Saramito at imag.fr
Tue Nov 1 15:02:53 CET 2011


Hi everybody,

I'm trying to generate an unstructured mixed triangle-quadrangle
2D meshes with gmsh. It works well until gmsh-2.5.0 but I have
a problem with the new gmsh-2.5.1 : the mesh contains only quadrangles.

I first generate a triangular use the "Recombine" operator with the
optional angle argument :
 // from the gmsh documentation (parag. 6.3.3):
 Recombine Surface { expression-list } | "*" < = expression >;
    Recombines the triangular meshes of the surfaces listed in 
    expression-list into mixed triangular/quadrangular meshes.
    The optional expression on the right hand side specifies the
    maximum difference (in degrees) allowed between the largest
    angle of a quadrangle and a right angle (a value of 0 would only
    accept quadrangles with right angles; a value of 90 would allow
    degenerate quadrangles; default value is 45). 

In attachment: the test file. I have tried to change the
"angle" value (0, 45, 90, etc), without any success with gmsh-2.5.1.

Thank you for any helps and/or comments,

Pierre

Note: this unstructured mixed mesh is used for testing a finite element
library (rheolef), so I do not want a structured mixed mesh.

-- 
Pierre.Saramito at imag.fr
Directeur de Recherche CNRS
Laboratoire Jean Kuntzmann, Grenoble, France
http://www-ljk.imag.fr/membres/Pierre.Saramito
-------------- next part --------------
n = 10.0;
hloc = 1.0/n;
Point(1) = {0, 0, 0, hloc};
Point(2) = {1, 0, 0, hloc};
Point(3) = {1, 1, 0, hloc};
Point(4) = {0, 1, 0, hloc};
Line(1) = {1,2};
Line(2) = {2,3};
Line(3) = {3,4};
Line(4) = {4,1};
Line Loop(5) = {1,2,3,4};
Plane Surface(6) = {5} ;
angle = 90.0;
Recombine Surface {6} = angle;