[Gmsh] making an equilateral mesh.

David Colignon David.Colignon at ulg.ac.be
Wed Oct 7 12:20:22 CEST 2009


Hi Colin,

what about this ?


Point(1) = {0,0,0,0.1};
Extrude {1,0,0} {  Point{1}; }
Extrude {0.5,0.866025403784,0} { Line{1}; }
Transfinite Line { 1 , 2 , 3 , 4 } =  5  ;
Transfinite Surface {5} Left ;


Cheers,

Dave

-- 
David Colignon, Ph.D.
Collaborateur Logistique du F.R.S.-FNRS
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Dr Colin J. Cotter wrote:
> Dear Gmsh list,
>   I have been trying to make a mesh of equilateral triangles by
> extruding a horizontal line at a 60 degree angle (later I will use
> periodic boundary conditions so I have an equilateral mesh on the
> torus). I have noticed that if you do this then the extrusion divides
> the quadrilaterals in the wrong direction and you don't get a Delaunay
> mesh (the equilateral one):
> 
> Point(1) = {0,0,0,0.1};
> Extrude {1,0,0} {
>   Point{1}; Layers{5};
> }
> Extrude {0.5,0.866025403784,0} {
>   Line{1}; Layers{5};
> }
> 
> but it works if you extrude at a -60 degree angle instead:
> 
> Point(1) = {0,0,0,0.1};
> Extrude {1,0,0} {
>   Point{1}; Layers{5};
> }
> Extrude {-0.5,0.866025403784,0} {
>   Line{1}; Layers{5};
> }
> 
> Is there a way to force Gmsh to produce a Delaunay mesh in the first case?
> 
> all the best
> --cjc
> 
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