[Gmsh] normals (again)

[John Borchardt]

Hi, please see attached screenshot.  The geometry normal is in red and
the mesh normals are in green -- and they are pointing in opposite
directions as far as I can tell.

The .geo file that produced this is:

Point(1) = {0,0,0,0.1};
Point(2) = {1,0,0,0.1};
Point(3) = {0,1,0,0.1};
Line(1) = {1,2};
Line(2) = {2,3};
Line(3) = {3,1};
Line Loop(4) = {1,2,3};
Plane Surface(5) = {4};

The console output is:

Info    : -------------------------------------------------------
Info    : Gmsh version   : 2.0.8
Info    : Build OS       : Linux
Info    : Build options  : GSL NETGEN JPEG PNG ZLIB MATHEVAL ANN
Info    : Build date     : Sat Aug 11 17:09:17 GMT 2007
Info    : Build host     : yellow
Info    : Packager       : buildd
Info    : Home directory : /home/john/
Info    : Launch date    : Fri Feb 15 11:54:09 2008
Info    : Command line   : gmsh plate.geo
Info    : -------------------------------------------------------
Info    : Reading 'plate.geo'
Info    : Read 'plate.geo'
Info    : Meshing 1D...
Info    : Meshing curve 1
Info    : Meshing curve 2
Info    : Meshing curve 3
Info    : Mesh 1D complete (0 s)
Info    : Mesh
Info    : Meshing 2D...
Info    : Meshing surface 5 (Plane, MeshAdapt+Delaunay)
Info    : Mesh 2D complete (0.004 s)
Info    : Mesh
Info    : 21 vertices 40 elements
Info    : Meshing 3D...
Info    : Mesh 3D complete (0 s)
Info    : Mesh
Info    : 21 vertices 40 elements
Info    : Reading 'plate.geo'
Info    : Read 'plate.geo'
Info    : Meshing 1D...
Info    : Meshing curve 1
Info    : Meshing curve 2
Info    : Meshing curve 3
Info    : Mesh 1D complete (0.004001 s)
Info    : Mesh
Info    : Meshing 2D...
Info    : Meshing surface 5 (Plane, MeshAdapt+Delaunay)
Info    : Mesh 2D complete (0 s)
Info    : Mesh
Info    : 22 vertices 42 elements


Any ideas what's going wrong?  I am using Ubuntu 7.10 x86-64 and I
installed via apt-get I believe.  Thanks!


--John






On Fri, Feb 15, 2008 at 11:32 AM, Christophe Geuzaine
<cgeuzaine at ulg.ac.be> wrote:
> John Borchardt wrote:
>  > Sorry I am looking in the manual and list archives and I still don't
>  > understand...
>  >
>  > Can you tell me if the default behaviour of gmsh is such that mesh
>  > element normals are opposite of the surface normals?  Am using version
>  > 2.0.8.
>  >
>  > E.g., when I mesh the following .geo, the element normals are opposite
>  > of the surface normal...
>
>
>  I cannot reproduce this on my machine...
>
>
>
>  >
>  >
>  > Point(1) = {0,0,0,0.1};
>  > Point(2) = {1,0,0,0.1};
>  > Point(3) = {0,1,0,0.1};
>  > Line(1) = {1,2};
>  > Line(2) = {2,3};
>  > Line(3) = {3,1};
>  > Line Loop(4) = {1,2,3};
>  > Plane Surface(5) = {4};
>  >
>  >
>  >
>  > Thanks,
>  >
>  >
>  > --John
>  >
>  > _______________________________________________
>  > 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
>
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