[Gmsh] Negative Jacobians in 2nd Order Mesh

[Christophe Geuzaine]

> On 23 Nov 2020, at 11:19, Nikhil Vaidya <nikhilvaidya91 at gmail.com> 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 <stephen.wornom at inria.fr> 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" <cgeuzaine at uliege.be>
> > To: "Nikhil Vaidya" <nikhilvaidya91 at gmail.com>
> > Cc: "gmsh" <gmsh at 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 <nikhilvaidya91 at gmail.com> 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
> >> _______________________________________________
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> > 
> > —
> > Prof. Christophe Geuzaine
> > University of Liege, Electrical Engineering and Computer Science
> > http://www.montefiore.ulg.ac.be/~geuzaine
> > 
> > 
> > 
> > 
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— 
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science 
http://people.montefiore.ulg.ac.be/geuzaine