Hi Jose,

In general, You should be careful with mesh formats and element types when using GMSH and FreeFEM++. I checked your geo file and modified the mesh format and version definition (see attached files). I tested the geo file by producing the mesh using
"gmsh pentagono.geo -3"
And then loaded and displayed the mesh with FreeFEM++
"FreeFem++ test_load.edp"

Seemed to work fine for me. I use FreeFEM 4.1, and GMSH v4.3.0.

Overall, these questions might be more suitable for FreeFEM mailing list / forum.

/Ugis

On 15/05/2020 08:55, Jose Juan Alonso del Rosario wrote:
Dear Ugis and colleages of GMSH,

Thank you for your suggestions. I have changed the loop orientation of the upper and lower faces of the pentagon and the whole volumen was meshed (no hole at the end). In addition the same error still happens.

"read mesh ok 0Mesh3, num Tetra:= 24011, num Vertice:= 5665 num boundary Triangles:= 6078 Mesh3::meshS, num Triangles:= 6078, num Vertice:= 3039 num boundary Edges:= 354 read mesh ok 0Mesh3, num Tetra:= 24011, num Vertice:= 5665 num boundary Triangles:= 6078 Mesh3::meshS, num Triangles:= 6078, num Vertice:= 3039 num boundary Edges:= 354  Bad orientation: The adj border element  defined by [  3 210 ]  is oriented in the same direction in element 3519 and in the element 367 ****** bug in mesh construction? orientation parameter?
S, num Triangles:= 6078, num Vertice:= 3039 num boundary Edges:= 354
 Bad orientation: The adj border element  defined by [  3 210 ]  is oriented in the same direction in element 3519 and in the element 367 ****** bug in mesh construction? orientation parameter? "

This is after several Optimize3D and Optimize 3d with NetGen and reading it with freefem++

I include the .geo code. It is a thick slice with a pentagonal hole. The gmsh is now 4.5.6 and the meshing options are MeshAdapt and Frontal. I have played with the signs of plane surfaces 14 and 15.

Thanks in advance!!!

Jose





El jue., 14 may. 2020 a las 13:54, Ugis Lacis (<[email protected] <mailto:[email protected]>>) escribió:

    Dear Jose,

    I think I have had similar error, when importing GMSH mesh into
    FreeFEM++, few years ago (although it seems that the error message
    might have changed). It turned out that the direction of loop
    definition in GMSH was the issue for me. See below my exchange
    with FreeFEM++ mailing list.

    Maybe it can be helpful for you.

    Best regards,
    Ugis Lacis
    Researcher
    KTH Mechanics

    
------------------------------------------------------------------------------------------------------------------------------------------------------------------
    -------- Forwarded Message --------
    Subject:    Re: [Freefempp] Issue with loading mesh from GMSH.
    Date:       Fri, 3 Aug 2018 09:41:29 +0200
    From:       Uģis Lācis <[email protected]>
    <mailto:[email protected]>
    To:         FreeFem mailing list <[email protected]>
    <mailto:[email protected]>



    Hi everyone,

    I managed to solve the issue myself. It turned out that the
    direction of GMSH loop was surviving till FreeFEM++ and while GMSH
    did not complain about anything, FreeFEM++ couldn't use the mesh.
    mesh2 could be fixed by changing signs in all lines within the
    line loop, i.e.,
    change
    Line Loop(5) = {18, 19, 20, 12, 7, 8};
    to
    Line Loop(5) = {-18, -19, -20, -12, -7, -8};

    Maybe this helps to someone at some point.

    Best,
    Ugis

    On 02/08/18 15:30, Uģis Lācis wrote:
    Dear FreeFEM++ users and developers,

    I have run into an issue which I am unable to solve by myself. I
    have been using FreeFEM++ together with GMSH without any problems
    for quite some time. Now, however, trying to load a 2D mesh
    generated by GMSH, gives me following error:

    Assertion fail : (area>0)
        line :281, in file ./include/fem.hpp

    I attach the corresponding geo and msh files of two meshes (mesh1
    - working fine, mesh2 - does not load), as well as edp file for
    reading and plotting the mesh.

    I have carefully checked that physical tags are applied correctly,
    I have tried exporting both in MSH and MESH (medit) formats, using
    GMSH versions 3.06 and 2.16.0, as well as using FreeFEM++ versions
    3.560000 and 3.610002, all try has led me to the same behaviour. I
    have identified that the issue comes from the surface mesh, if I
    export only line mesh (comment out "Physical Surface(11) = {3,4};"
    from mesh2.geo and run "gmsh -2 mesh2.geo"), then it loads fine.
    But checking the mesh within GMSH, everything seems to be
    perfectly fine...

    Do you have any suggestions on how to solve this issue?

    Best regards,
    Ugis Lacis
    Researcher
    KTH Mechanics
    
------------------------------------------------------------------------------------------------------------------------------------------------------------------


    On 14/05/2020 12:03, Jose Juan Alonso del Rosario wrote:
    Dear colleages

    I am trying to build the mesh for a slice with a pentagonal hole.
    GMSH runs properly with good quality tets but when trying to read
    it from freefem++ the error is:

    " Bad orientation: The adj border element  defined by [  16 246 ]
     is oriented in the same direction in element 3922 and in the
    element 446 ****** bug in mesh construction? orientation parameter?
      current line = 12 mpirank 1 / 2
    "
    Can you give any advice on this?

    Thanks in advance

    Jose

-- Prof. Dr. Jose Juan Alonso del Rosario
    Applied Physics Dept.,
    Naval and Oceanic Engineering.
    University of Cadiz.
    Avda Rep Saharaui s/n. Puerto Real, 11510, Cadiz, Spain
    Tlf: +34 956 016054
    Fax: +34 956016079
    Secretary: +34 956016078

    "All I wanna say is that they don't really care about us",
    Michael Jackson

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--
Prof. Dr. Jose Juan Alonso del Rosario
Applied Physics Dept.,
Naval and Oceanic Engineering.
University of Cadiz.
Avda Rep Saharaui s/n. Puerto Real, 11510, Cadiz, Spain
Tlf: +34 956 016054
Fax: +34 956016079
Secretary: +34 956016078

"All I wanna say is that they don't really care about us", Michael Jackson

Attachment: pentagono.geo
Description: application/vnd.dynageo

// Level of output                                                              
                                      
verbosity = 0;

load "msh3"
load "gmsh";
load "medit";

mesh3 Th3I=gmshload3("pentagono.msh");

fespace Uh (Th3I,P1);

medit("test",Th3I);
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