# [Gmsh] bug report

Christophe Geuzaine geuzaine at acm.caltech.edu
Sat Feb 28 02:19:58 CET 2004

Alexandre Chatelain wrote:
> Hello,
>
> I obtained a segmentation fault trying to make a 3D mesh out of the
> attached geo file.

You cannot mesh a volume with the automatic Delaunay algorithm if its
boundary is meshed with quadrangles! (We could add a test in the code to
prevent the crash, but well...)

Here is one way to generate hexas:

Point(1) = {0, 0, 0, 0.1};
Point(2) = {0, 1, 0, 0.1};
Point(3) = {1, 1, 0, 0.1};
Point(4) = {1, 0, 0, 0.1};
Point(6) = {1, 0.3032932906528346, -0.7173560908995228, 0.1};
Point(10) = {0, 0.3032932906528346, -0.7173560908995228, 0.1};
Line (1) = {2, 3};
Line (2) = {3, 4};
Line (3) = {4, 1};
Line (4) = {1, 2};
Line (8) = {3, 6};
Line (9) = {6, 10};
Line (10) = {10, 2};
Circle (13) = {4, 3, 6} Plane{0, 0, 1};
Circle (17) = {1, 2, 10} Plane{0, 0, 1};
Line Loop (1000006) = {2, 3, 4, 1};
Plane Surface (6) = {1000006};
Line Loop (1000014) = {2, 13, -8};
Ruled Surface (14) = {1000014};
Line Loop (1000018) = {3, 17, -9, -13};
Ruled Surface (18) = {1000018};
Line Loop (1000021) = {-10, -17, 4};
Ruled Surface (21) = {1000021};
Line Loop (1000023) = {8, 9, 10, 1};
Plane Surface (23) = {1000023};
Surface Loop (2000025) = {14, 6, 18, 21, 23};
Volume (1000025) = {2000025};
Transfinite Line {8,2,4,10,1,9,3,17,13} = 20;
Transfinite Surface {23} = {3,2,10,6};
Transfinite Surface {14} = {3,4,6};
Transfinite Surface {6} = {2,3,4,1};
Transfinite Surface {21} = {2,1,10};
Transfinite Surface {18} = {6,4,1,10};
Recombine Surface {14,23,21,6,18};
Transfinite Volume{1000025} = {2,10,1,3,6,4};

Cheers,

Christophe

>
> Sincerely yours,
> Alexandre Chatelain.
>
>
>
> ------------------------------------------------------------------------
>
> Point(1) = {0, 0, 0, 0.1};
> Point(2) = {0, 1, 0, 0.1};
> Point(3) = {1, 1, 0, 0.1};
> Point(4) = {1, 0, 0, 0.1};
> Point(6) = {1, 0.3032932906528346, -0.7173560908995228, 0.1};
> Point(10) = {0, 0.3032932906528346, -0.7173560908995228, 0.1};
> Line (1) = {2, 3};
> Line (2) = {3, 4};
> Line (3) = {4, 1};
> Line (4) = {1, 2};
> Line (8) = {3, 6};
> Line (9) = {6, 10};
> Line (10) = {10, 2};
> Circle (13) = {4, 3, 6} Plane{0, 0, 1};
> Circle (17) = {1, 2, 10} Plane{0, 0, 1};
> Line Loop (1000006) = {2, 3, 4, 1};
> Plane Surface (6) = {1000006};
> Line Loop (1000014) = {2, 13, -8};
> Ruled Surface (14) = {1000014};
> Line Loop (1000018) = {3, 17, -9, -13};
> Ruled Surface (18) = {1000018};
> Line Loop (1000021) = {-10, -17, 4};
> Ruled Surface (21) = {1000021};
> Line Loop (1000023) = {8, 9, 10, 1};
> Plane Surface (23) = {1000023};
> Surface Loop (2000025) = {14, 6, 18, 21, 23};
> Volume (1000025) = {2000025};
> Transfinite Line {8,2,4,10,1,9,3,17,13} = 20;
> Transfinite Surface {23} = {3,2,10,6};
> Transfinite Surface {14} = {4,3,6};
> Transfinite Surface {6} = {2,3,4,1};
> Transfinite Surface {21} = {2,1,10};
> Transfinite Surface {18} = {6,4,1,10};
> Recombine Surface {14,23,21,6,18};
>
>
> ------------------------------------------------------------------------
>
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--
Christophe A. Geuzaine
Applied and Computational Mathematics, Caltech
geuzaine at acm.caltech.edu - http://geuz.org