[Gmsh] splines in 3-d space

[Christophe Geuzaine]

Durufle marc wrote:
> Hi, I meet some problems when i try to use splines in
> 3-d space. The geo file is :
> 
> lc = 0.2;
> 
> a = 1.0;
> b = 1.0;
> c = 1.0;
> p = 1.1;
> 
> Mesh.Algorithm = 1;
> Mesh.Algorithm3D = 4;
> 
> 
> Point(36) = {0.0,b,3*c,lc};
> Point(37) = {-a,0.0,2.5*c,lc};
> Point(38) = {0.0,-b,2*c,lc};
> Point(39) = {a,0.0,1.5*c,lc};
> Point(40) = {0.0,b,c,lc};
> Point(41) = {-a,0.0,0.5*c,lc};
> Point(42) = {0.0,-b,0.0,lc};
> Point(43) = {a,0.0,-0.5*c,lc};
> Point(44) = {0.0,b,-c,lc};
> Point(45) = {-a,0.0,-1.5*c,lc};
> Point(46) = {0.0,-b,-1.8*c,lc};
> Point(47) = {0.0,p,3*c,lc};
> Point(48) = {-p,0.0,2.5*c,lc};
> Point(49) = {0.0,-p,2*c,lc};
> Point(50) = {p,0.0,1.5*c,lc};
> Point(51) = {0.0,p,c,lc};
> Point(52) = {-p,0.0,0.5*c,lc};
> Point(53) = {0.0,-p,0.0,lc};
> Point(54) = {p,0.0,-0.5*c,lc};
> Point(55) = {0.0,p,-c,lc};
> Point(56) = {-p,0.0,-1.5*c,lc};
> Point(57) = {0.0,-p,-1.8*c,lc};
> Point(58) = {0.0,b,3*c-0.2,lc};
> Point(59) = {-a,0.0,2.5*c-0.2,lc};
> Point(60) = {0.0,-b,2*c-0.2,lc};
> Point(61) = {a,0.0,1.5*c-0.2,lc};
> Point(62) = {0.0,b,c-0.2,lc};
> Point(63) = {-a,0.0,0.5*c-0.2,lc};
> Point(64) = {0.0,-b,0.0-0.2,lc};
> Point(65) = {a,0.0,-0.5*c-0.2,lc};
> Point(66) = {0.0,b,-c-0.2,lc};
> Point(67) = {-a,0.0,-1.5*c-0.2,lc};
> Point(68) = {0.0,-b,-1.8*c-0.2,lc};
> Point(69) = {0.0,p,3*c-0.2,lc};
> Point(70) = {-p,0.0,2.5*c-0.2,lc};
> Point(71) = {0.0,-p,2*c-0.2,lc};
> Point(72) = {p,0.0,1.5*c-0.2,lc};
> Point(73) = {0.0,p,c-0.2,lc};
> Point(74) = {-p,0.0,0.5*c-0.2,lc};
> Point(75) = {0.0,-p,0.0-0.2,lc};
> Point(76) = {p,0.0,-0.5*c-0.2,lc};
> Point(77) = {0.0,p,-c-0.2,lc};
> Point(78) = {-p,0.0,-1.5*c-0.2,lc};
> Point(79) = {0.0,-p,-1.8*c-0.2,lc};
> 
> 
> Spline(49) = {36,37,38,39,40,41,42,43,44,45,46};
> Spline(50) = {47,48,49,50,51,52,53,54,55,56,57};
> Line(51) = {36,47};
> Line(52) = {46,57};
> 
> Line Loop(23) = {49,52,-50,-51};
> 
> Ruled Surface(23) = {23};
> 
> Physical Surface(1) = {23};
> 
> The 1-D mesh generated seems coorect, the points
> belong to the defined splines. The 2-D mesh is quite
> strange, some triangles are outside of the spline. How
> can i correct this default, is there a way to correct
> that ?

That's a limitation of the current version of the code: it projects the 
surface in a plane to generate the mesh--and thus it will fail if the 
projection is not one to one (if the map is not bijective).

With the current version the only fix is to divide the surface in 
smaller pieces. The next major version will fix that.



> 
> Thank you.
> 
> 
> 
> 
> 
> 	
> 
> 	
> 		
> ___________________________________________________________________________ 
> Yahoo! Mail réinvente le mail ! Découvrez le nouveau Yahoo! Mail et son interface révolutionnaire.
> http://fr.mail.yahoo.com
> _______________________________________________
> gmsh mailing list
> gmsh at geuz.org
> http://www.geuz.org/mailman/listinfo/gmsh
> 


-- 
Christophe Geuzaine
Assistant Professor, Case Western Reserve University, Mathematics
http://www.case.edu/artsci/math/geuzaine