[Gmsh] Failed to mesh in 2D polygon with 2nd order elements

[Guangran Kevin Zhu]

Hello,

The "Impose C1 continuity (only for 2D-plane, order 2 and order3)" flag is
the culprit. If i check it, i will receive the negative jacobian problem. If
no, the mesh generator works fine. Does someone know the reason behind?

Kevin


On 10/30/07, Christophe Geuzaine <cgeuzaine at ulg.ac.be> wrote:
>
> Guangran Kevin Zhu wrote:
> > Hello,
> >
> > I am using GMSH 2.0.8 on Windows XP. GMSH failed to generate 2nd order
> > elements with a simple 2D polygon, while using GMSH 1.6 was successful.
> > Has anyone ecountered a similar problem on other platforms? What is the
> > work around?
>
> Works over here...
>
> >
> > I list the geo file and the error message below.
> >
> > Kevin
> >
> > ===================================================
> > // Gmsh project created on Tue Oct 30 14:59:54 2007
> > Point(1) = {0.065,0.126,0,0.1};
> > Point(2) = {0.093,0.35,0,0.1};
> > Point(3) = {-0.029,0.063,0,0.1};
> > Point(4) = {-0.061,0.061,0,0.1};
> > Point(5) = {-0.07,0.043 ,0,0.1};
> > Point(6) = {-0.05,0.018,0,0.1};
> > Point(7) = {-0.047,0.044,0,0.1};
> > Line(1) = {3,4};
> > Line(2) = {4,5};
> > Line(3) = {5,6};
> > Line(4) = {6,7};
> > Line(5) = {7,3};
> > Line Loop(6) = {2,3,4,5,1};
> > Plane Surface(7) = {6};
> > ====================================================
> >
> > Error message
> > ====================================================
> > Warning : Triangle 578 (15 1 5) has negative Jacobian
> > Warning : Triangle 582 (0 170 10) has negative Jacobian
> > Warning : Triangle 585 (176 22 19) has negative Jacobian
> > Warning : Triangle 595 (180 13 6) has negative Jacobian
> > Warning : Triangle 618 (8 13 188) has negative Jacobian
> > Warning : Triangle 625 (190 23 11) has negative Jacobian
> > Error   : Some triangles have negative Jacobians in surface 7
> > ====================================================
> >
> >
> > ------------------------------------------------------------------------
> >
> > _______________________________________________
> > gmsh mailing list
> > gmsh at geuz.org
> > http://www.geuz.org/mailman/listinfo/gmsh
>
>
> --
> Prof. Christophe Geuzaine
> University of Liege, Electrical Engineering and Computer Science
> http://www.montefiore.ulg.ac.be/~geuzaine
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.geuz.org/pipermail/gmsh/attachments/20071031/c37eea71/attachment.html>