Hello Nicolas, The issue is that you do "Point ... In Volume" for a point that is actually on the boundary of the volume - actually on a curve.
Quick solution: add a global fragment operation on the volumes and the points - it will automatically embed the point in all the required entities. (Here it will need to split a curve + redefine all the surfaces/volumes touched...) Cheers, Christophe
script_Domaine_frag.geo
Description: Binary data
> On 13 May 2020, at 08:44, Karin&NiKo <niko.ka...@gmail.com> wrote: > > Christophe, > > I see that the mesh contains duplicate nodes : > Info : Checking for duplicate nodes... > Warning : Vertex 79 (0, 0, 999.9999999999999) already exists in the > mesh with tolerance 4.66905e-05: Vertex 17 (0, 0, 1000) > Error : 1 duplicate node: see `duplicate_node.pos' > > I am quite sure that it comes from the point I define and ask the mesh to > embed (lines 21-26 of the script - if I remove it, the script doesn't > complain anymore) : > c0[] = Point{4}; // c0 contains the coords in indexes 0,1,2 > c1[] = Point{3}; > p=newp; // newp is command to generate a new point number - we store it in p > Point(p)={0,0, (c1[2]-c0[2])/2}; > Point{p} In Volume{1}; > Physical Point("PGHM") = {p}; > > Is there a way to set a sharper value to some parameter to avoid this? I > tried to Coherence Mesh but it causes me trouble in the computation based on > this mesh (it seems to become invalide in some sense). > > Nicolas > > > Le mar. 12 mai 2020 à 14:06, Karin&NiKo <niko.ka...@gmail.com> a écrit : > Thanks for the tip Christophe! > "Mesh.Algorithm3D = 10;" is indeed faster and produces less elements. > > Nicolas > > Le mar. 12 mai 2020 à 13:28, Christophe Geuzaine <cgeuza...@uliege.be> a > écrit : > > > > On 12 May 2020, at 11:49, Karin&NiKo <niko.ka...@gmail.com> wrote: > > > > Dear Gmsh Gurus, > > > > I am facing some troubles with a brep CAD I am trying to mesh with Gmsh. > > If I try the meshing default settings, the mesh is being built and Gmsh is > > proud to announce that no illegal tet stand in the mesh. *But* if I simply > > run "gmsh -check", Gmsh admits that zero volume tets stay in the mesh. So > > it is unusable for computation. > > There maybe too many messages, but the optimizer indeed reports that there > are 6 tets below the quality threshold in volume 2 with the default algo (we > should issue a warning if the quality is indeed approaching zero): > > Info : Optimizing volume 2 > Info : Optimization starts (volume = 3.52969e+07) with worst = 0 / average > = 0.757222: > Info : 0.00 < quality < 0.10 : 212 elements > Info : 0.10 < quality < 0.20 : 362 elements > Info : 0.20 < quality < 0.30 : 166 elements > Info : 0.30 < quality < 0.40 : 222 elements > Info : 0.40 < quality < 0.50 : 287 elements > Info : 0.50 < quality < 0.60 : 765 elements > Info : 0.60 < quality < 0.70 : 3802 elements > Info : 0.70 < quality < 0.80 : 7720 elements > Info : 0.80 < quality < 0.90 : 4721 elements > Info : 0.90 < quality < 1.00 : 4214 elements > Info : 321 edge swaps, 0 node relocations (volume = 3.52969e+07): worst = > 0 / average = 0.765757 (Wall 0.022079s, CPU 0.022s) > Info : 338 edge swaps, 0 node relocations (volume = 3.52969e+07): worst = > 0 / average = 0.765884 (Wall 0.0357411s, CPU 0.035583s) > Info : 339 edge swaps, 0 node relocations (volume = 3.52969e+07): worst = > 0 / average = 0.765909 (Wall 0.0503662s, CPU 0.050068s) > Info : 6 ill-shaped tets are still in the mesh > > > > I have succeeded in producing a correct mesh by using the Frontal 3D > > algorithm (Mesh.Algorithm3D = 4;). > > Perhaps a check of the presence of zero volume elements could be an > > interesting enhancement. > > You can also try > > Mesh.Algorithm3D = 10; > > which is (here a bit) faster. > > Christophe > > > > You'll find all necessary files in the attached archive. > > > > Regards, > > Nicolas > > <foo.tar.gz>_______________________________________________ > > gmsh mailing list > > gmsh@onelab.info > > http://onelab.info/mailman/listinfo/gmsh > > — > Prof. Christophe Geuzaine > University of Liege, Electrical Engineering and Computer Science > http://www.montefiore.ulg.ac.be/~geuzaine > > > > _______________________________________________ > gmsh mailing list > gmsh@onelab.info > http://onelab.info/mailman/listinfo/gmsh — Prof. Christophe Geuzaine University of Liege, Electrical Engineering and Computer Science http://www.montefiore.ulg.ac.be/~geuzaine
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