[Gmsh] Volume Meshing a sphere with reasonably homogenous edgelengths

[David Colignon]

Hi,

did you try the Delaunay 3D algorithm instead of the default Netgen ? (Options -> Mesh -> General -> 3D algorithm -> Delaunay ?

Dave

-- 
David Colignon, Ph.D.
ELAP - Service d'Electricité Appliquée
Institut Montefiore B28
Université de Liège
4000 Liège - BELGIQUE
Tél: +32 (0)4 366 37 32
Fax: +32 (0)4 366 29 10
http://elap.montefiore.ulg.ac.be



Neilen Marais wrote:
>  Hi.
> 
> I'm trying to mesh a sphere with a radius of 1m and a tetrahedral edge
> length around 1/6 (i.e 0.166666666666667), but I'm having real trouble
> getting a nice mesh. 
> 
> At the moment I get the longest and shortes edgelenghts like this:
> 
> max:  0.48267512213
> min:  0.055869461987
> 
> The minimum edge lenght is kinda OK, but the max is way off from what is
> acceptable. Is there any way I can force gmsh to generate a more
> homogenous mesh? I have tried the mesh-optimisation commands, but they
> seem to consider only individual elment quality, rather than the global
> min / max edge lengths.
> 
> The surface mesh seems to be very nice and homogenous, it's only the
> volume mesh that is inhomogenous.
> 
> I'm using this geometry file with gmsh 2.0, but have also tried
> variations with more surfaces:
> 
> lc = 1/6;
> radius = 1;
> Point(1) = {0.0,0.0,0.0,lc};
> Point(2) = {radius,0.0,0.0,lc};
> Point(3) = {0,radius,0.0,lc};
> Circle(1) = {2,1,3};
> Point(4) = {-radius,0,0.0,lc};
> Point(5) = {0,-radius,0.0,lc};
> Circle(2) = {3,1,4};
> Circle(3) = {4,1,5};
> Circle(4) = {5,1,2};
> Point(6) = {0,0,-radius,lc};
> Point(7) = {0,0,radius,lc};
> Circle(5) = {3,1,6};
> Circle(6) = {6,1,5};
> Circle(7) = {5,1,7};
> Circle(8) = {7,1,3};
> Circle(9) = {2,1,7};
> Circle(10) = {7,1,4};
> Circle(11) = {4,1,6};
> Circle(12) = {6,1,2};
> Line Loop(13) = {2,8,-10};
> Ruled Surface(14) = {13};
> Line Loop(15) = {10,3,7};
> Ruled Surface(16) = {15};
> Line Loop(17) = {-8,-9,1};
> Ruled Surface(18) = {17};
> Line Loop(19) = {-11,-2,5};
> Ruled Surface(20) = {19};
> Line Loop(21) = {-5,-12,-1};
> Ruled Surface(22) = {21};
> Line Loop(23) = {-3,11,6};
> Ruled Surface(24) = {23};
> Line Loop(25) = {-7,4,9};
> Ruled Surface(26) = {25};
> Line Loop(27) = {-4,12,-6};
> Ruled Surface(28) = {27};
> Surface Loop(29) = {28,26,16,14,20,24,22,18};
> Volume(30) = {29};
> 
> Thanks
> Neilen
> 
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