[Gmsh] Hexa mesh with extruded mesh

[Umut Tabak]

Dear all,

In a hexahedral mesh generation, I can do the tetrahedral meshing 
without problems with the below piece of code. But uncommenting the 
commented lines results in this problem : My surface is extruded, 
however the surfaces in the direction of the extrusion are meshed with 
quadrangles and the others with triangles and (I guess) as a result, I 
can not get a hexahedral mesh for a simple box geometry.  I am sure I am 
missing sth simple from the manual and your help is appreciated.

P.S. I think I can define 8 corners of my box, define lines and surfaces 
with transfinite to end up with the hexa mesh. But I wondered the 
correct usage of extruded mesh option if I understood correctly from the 
manual with the code below(lines uncommented).

Thanks for the replies in advance. Attached also the include file.

Umut

    11 Include "truck3d_1r.geo";
    12
    13 // Transfinite Line{1} = 21 ;
    14 // Transfinite Line{2,4} = 11;
    15 // Transfinite Line{3} = 21;
    16 // Transfinite Surface{10} = {1,2,3,4};
    17 // Recombine Surface { 10 };
    18 // Physical Surface(4) = {10};
    19 // vol[]=Extrude {0.0,0.0,0.5}{   
Surface{10};Layers{10};Recombine; };
    20 // vol[]=Extrude {0.0,0.0,0.5}{ Surface{10};Layers{10}; };
    21 vol[]=Extrude {0.0,0.0,0.5}{ Surface{10}; Layers{5}; };
    22 //Transfinite Volume {11} = vol[1] ;
    23 Physical Volume (11) = { vol[1] } ;
    24 // binary format
    25 // Mesh.MshBinary = 1 ;  // GMSH 2.2.4
    26 // Mesh.Binary = 1 ;         // GMSH 2.2.5 changed to this
    27 // color
    28 // Mesh.Color.Quadrangles ;
    29 // Nastran bdf format : option value is 31 for BDF output
    30 // Mesh.Format = 31 ;


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