# [Gmsh] Ellipsoid with OpenCASCADE kernel

Christophe Geuzaine cgeuzaine at uliege.be
Thu Mar 1 18:53:56 CET 2018

```
> On 1 Mar 2018, at 09:30, Stephan Köhler <koehlste at unixmail.tu-freiberg.de> wrote:
>
> Hello,
> I try to build a mesh of an ellipsoid with gmsh 3.0.6 and the
> OpenCASCADE kernel, but the surface
> mesh is not so pretty and it happens a strange thing curved surface.

"Surface" builds "a" bspline surface going through the curves. I would do this to build an ellipsoid:

Sphere(1) = {0, 0, 0, 0.5};
Dilate {{0, 0, 0}, {1.5, 1, 0.5}} { Volume{1}; }
Characteristic Length{:} = 0.1;
Mesh.Algorithm = 6;

> I've done some research, but i couldn't find a
> solution. So I hope you can help me. It works without the OpenCASCADE
> kernel, but I need the boolean operation.
>
> Thank you very much,
> Stephan
>
> ////////////////////////////////////////
> // ellipsoid
>
>
> // middle point
> Point(9) = {0.5, 0.5, 0.5};
>
> // major axis
> Point(10) = {0.7, 0.5, 0.5};
> Point(11) = {0.5, 0.5, 0.7};
> Point(12) = {0.3, 0.5, 0.5};
> Point(13) = {0.5, 0.5, 0.3};
> Point(14) = {0.5, 1.5, 0.5};
> Point(15) = {0.5, -0.5, 0.5};
>
> // ellipsoid, lines
> Ellipse(13) = {10, 9, 11, 11};
> Ellipse(14) = {12, 9, 11, 11};
> Ellipse(15) = {12, 9, 13, 13};
> Ellipse(16) = {13, 9, 10, 10};
>
> Ellipse(17) = {14, 9, 10, 10};
> Ellipse(18) = {14, 9, 11, 11};
> Ellipse(19) = {14, 9, 12, 12};
> Ellipse(20) = {14, 9, 13, 13};
>
> Ellipse(21) = {15, 9, 10, 10};
> Ellipse(22) = {15, 9, 11, 11};
> Ellipse(23) = {15, 9, 12, 12};
> Ellipse(24) = {15, 9, 13, 13};
>
>
> // line loops
> Line Loop(1) = {16,17,-20};
> Surface(1) = {1};
>
>
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—
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science
http://www.montefiore.ulg.ac.be/~geuzaine

Free software: http://gmsh.info | http://getdp.info | http://onelab.info

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