Dear Christophe, I thank you so warmly for your help. I was quite lost with this problem and your fix is really easy! It would perhaps be useful to add this precise feature to the demo scripts. I saw that several users when wondering about it. And once again, congratulations to JF and you : Gmsh rocks!!!
Nicolas Le lun. 18 mai 2020 à 15:23, Christophe Geuzaine <[email protected]> a écrit : > > 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 > > > > > > On 13 May 2020, at 08:44, Karin&NiKo <[email protected]> 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 <[email protected]> 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 <[email protected]> > a écrit : > > > > > > > On 12 May 2020, at 11:49, Karin&NiKo <[email protected]> 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 > > > [email protected] > > > 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 > > [email protected] > > 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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