Re: [Gmsh] Negative Jacobians in 2nd Order Mesh
Thanks, I'll check it out. Best, Nikhil On Thu, Nov 26, 2020, 12:53 PM Christophe Geuzaine wrote: > > > > On 23 Nov 2020, at 11:19, Nikhil Vaidya > wrote: > > > > I changed my geometry slightly, and the negative jacobians problem has > returned. Is there some general second-order meshing workflow (involving > smoothing steps) one can follow to avoid this problem? > > "-optimize_ho" applies the default strategy (elastic smoothing followed by > brute-force optimization). See all the "HighOrder" options to fine-tune the > parameters. With the API you can also call all the steps individually. > > Christophe > > > > > Best, > > Nikhil > > > > On Sat, Sep 5, 2020 at 7:32 AM Stephen Wornom > wrote: > > > > Hello > > Please let the list know if > > > Try the high-order mesh optimizer: "-optimize_ho" on the command line. > > fixed the problem, > > Stephen > > > > > > > > ----- Original Message ----- > > > From: "Christophe Geuzaine" > > > To: "Nikhil Vaidya" > > > Cc: "gmsh" > > > Sent: Friday, September 4, 2020 2:19:36 PM > > > Subject: Re: [Gmsh] Negative Jacobians in 2nd Order Mesh > > > > >> On 4 Sep 2020, at 13:49, Nikhil Vaidya > wrote: > > >> > > >> Hello, > > >> > > >> I have a geometry for which 1st order tetrahedral meshing works fine > (with no > > >> negative jacobians). For the 2nd order case, I get a few negative > jacobians. > > >> This problem does not go away even when I try to regularize the mesh > or reduce > > >> mesh sizes in certain regions with small geometric features. > > >> > > >> Does someone have a suggestion? > > > > > Hello > > > > > > Christophe > > > > > >> > > >> Best regards, > > >> Nikhil > > >> ___ > > >> 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 > > ___ > > gmsh mailing list > > gmsh@onelab.info > > http://onelab.info/mailman/listinfo/gmsh > > — > Prof. Christophe Geuzaine > University of Liege, Electrical Engineering and Computer Science > http://people.montefiore.ulg.ac.be/geuzaine > > > > > ___ gmsh mailing list gmsh@onelab.info http://onelab.info/mailman/listinfo/gmsh
Re: [Gmsh] Negative Jacobians in 2nd Order Mesh
> On 23 Nov 2020, at 11:19, Nikhil Vaidya wrote: > > I changed my geometry slightly, and the negative jacobians problem has > returned. Is there some general second-order meshing workflow (involving > smoothing steps) one can follow to avoid this problem? "-optimize_ho" applies the default strategy (elastic smoothing followed by brute-force optimization). See all the "HighOrder" options to fine-tune the parameters. With the API you can also call all the steps individually. Christophe > > Best, > Nikhil > > On Sat, Sep 5, 2020 at 7:32 AM Stephen Wornom wrote: > > Hello > Please let the list know if > > Try the high-order mesh optimizer: "-optimize_ho" on the command line. > fixed the problem, > Stephen > > > > - Original Message - > > From: "Christophe Geuzaine" > > To: "Nikhil Vaidya" > > Cc: "gmsh" > > Sent: Friday, September 4, 2020 2:19:36 PM > > Subject: Re: [Gmsh] Negative Jacobians in 2nd Order Mesh > > >> On 4 Sep 2020, at 13:49, Nikhil Vaidya wrote: > >> > >> Hello, > >> > >> I have a geometry for which 1st order tetrahedral meshing works fine (with > >> no > >> negative jacobians). For the 2nd order case, I get a few negative > >> jacobians. > >> This problem does not go away even when I try to regularize the mesh or > >> reduce > >> mesh sizes in certain regions with small geometric features. > >> > >> Does someone have a suggestion? > > > Hello > > > > Christophe > > > >> > >> Best regards, > >> Nikhil > >> ___ > >> 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 > ___ > gmsh mailing list > gmsh@onelab.info > http://onelab.info/mailman/listinfo/gmsh — Prof. Christophe Geuzaine University of Liege, Electrical Engineering and Computer Science http://people.montefiore.ulg.ac.be/geuzaine ___ gmsh mailing list gmsh@onelab.info http://onelab.info/mailman/listinfo/gmsh
Re: [Gmsh] Negative Jacobians in 2nd Order Mesh
I changed my geometry slightly, and the negative jacobians problem has returned. Is there some general second-order meshing workflow (involving smoothing steps) one can follow to avoid this problem? Best, Nikhil On Sat, Sep 5, 2020 at 7:32 AM Stephen Wornom wrote: > > Hello > Please let the list know if > > Try the high-order mesh optimizer: "-optimize_ho" on the command line. > fixed the problem, > Stephen > > > > - Original Message - > > From: "Christophe Geuzaine" > > To: "Nikhil Vaidya" > > Cc: "gmsh" > > Sent: Friday, September 4, 2020 2:19:36 PM > > Subject: Re: [Gmsh] Negative Jacobians in 2nd Order Mesh > > >> On 4 Sep 2020, at 13:49, Nikhil Vaidya > wrote: > >> > >> Hello, > >> > >> I have a geometry for which 1st order tetrahedral meshing works fine > (with no > >> negative jacobians). For the 2nd order case, I get a few negative > jacobians. > >> This problem does not go away even when I try to regularize the mesh or > reduce > >> mesh sizes in certain regions with small geometric features. > >> > >> Does someone have a suggestion? > > > Hello > > > > Christophe > > > >> > >> Best regards, > >> Nikhil > >> ___ > >> 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 > ___ gmsh mailing list gmsh@onelab.info http://onelab.info/mailman/listinfo/gmsh
Re: [Gmsh] Negative Jacobians in 2nd Order Mesh
Hi Christophe, Your suggestion solved my problem. Thanks! Best, Nikhil On Fri, Sep 4, 2020, 2:19 PM Christophe Geuzaine wrote: > > > > On 4 Sep 2020, at 13:49, Nikhil Vaidya wrote: > > > > Hello, > > > > I have a geometry for which 1st order tetrahedral meshing works fine > (with no negative jacobians). For the 2nd order case, I get a few negative > jacobians. This problem does not go away even when I try to regularize the > mesh or reduce mesh sizes in certain regions with small geometric features. > > > > Does someone have a suggestion? > > Try the high-order mesh optimizer: "-optimize_ho" on the command line. > > Christophe > > > > > Best regards, > > Nikhil > > ___ > > 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
Re: [Gmsh] Negative Jacobians in 2nd Order Mesh
If you do not need curved elements set Mesh.SecondOrderLinear = 1 -- jeremy theler www.seamplex.com On Fri, Sep 4, 2020, 11:22 Stephen Wornom wrote: > Tell the list if it removes the negative values. > Thanks, > Stephen > > - Original Message - > > From: "Christophe Geuzaine" > > To: "Nikhil Vaidya" > > Cc: gmsh@onelab.info > > Sent: Friday, September 4, 2020 2:19:36 PM > > Subject: Re: [Gmsh] Negative Jacobians in 2nd Order Mesh > > >> On 4 Sep 2020, at 13:49, Nikhil Vaidya > wrote: > >> > >> Hello, > >> > >> I have a geometry for which 1st order tetrahedral meshing works fine > (with no > >> negative jacobians). For the 2nd order case, I get a few negative > jacobians. > >> This problem does not go away even when I try to regularize the mesh or > reduce > >> mesh sizes in certain regions with small geometric features. > >> > >> Does someone have a suggestion? > > > > Try the high-order mesh optimizer: "-optimize_ho" on the command line. > > > > Christophe > > > >> > >> Best regards, > >> Nikhil > >> ___ > >> 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 > > ___ > gmsh mailing list > gmsh@onelab.info > http://onelab.info/mailman/listinfo/gmsh > ___ gmsh mailing list gmsh@onelab.info http://onelab.info/mailman/listinfo/gmsh
Re: [Gmsh] Negative Jacobians in 2nd Order Mesh
Tell the list if it removes the negative values. Thanks, Stephen - Original Message - > From: "Christophe Geuzaine" > To: "Nikhil Vaidya" > Cc: gmsh@onelab.info > Sent: Friday, September 4, 2020 2:19:36 PM > Subject: Re: [Gmsh] Negative Jacobians in 2nd Order Mesh >> On 4 Sep 2020, at 13:49, Nikhil Vaidya wrote: >> >> Hello, >> >> I have a geometry for which 1st order tetrahedral meshing works fine (with no >> negative jacobians). For the 2nd order case, I get a few negative jacobians. >> This problem does not go away even when I try to regularize the mesh or >> reduce >> mesh sizes in certain regions with small geometric features. >> >> Does someone have a suggestion? > > Try the high-order mesh optimizer: "-optimize_ho" on the command line. > > Christophe > >> >> Best regards, >> Nikhil >> ___ >> 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 ___ gmsh mailing list gmsh@onelab.info http://onelab.info/mailman/listinfo/gmsh
Re: [Gmsh] Negative Jacobians in 2nd Order Mesh
> On 4 Sep 2020, at 13:49, Nikhil Vaidya wrote: > > Hello, > > I have a geometry for which 1st order tetrahedral meshing works fine (with no > negative jacobians). For the 2nd order case, I get a few negative jacobians. > This problem does not go away even when I try to regularize the mesh or > reduce mesh sizes in certain regions with small geometric features. > > Does someone have a suggestion? Try the high-order mesh optimizer: "-optimize_ho" on the command line. Christophe > > Best regards, > Nikhil > ___ > 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
