[Gmsh] bad orientation
Ugis Lacis
ugis.lacis at gmail.com
Fri May 15 09:44:28 CEST 2020
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 (<ugis.lacis at gmail.com
> <mailto:ugis.lacis at gmail.com>>) 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 <ugis.lacis at gmail.com>
> <mailto:ugis.lacis at gmail.com>
> To: FreeFem mailing list <freefempp at ljll.math.upmc.fr>
> <mailto:freefempp at ljll.math.upmc.fr>
>
>
>
> 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
>>
>> _______________________________________________
>> gmsh mailing list
>> gmsh at onelab.info <mailto:gmsh at onelab.info>
>> http://onelab.info/mailman/listinfo/gmsh
>
>
>
> --
> 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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// 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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