[Gmsh] Making an Ellipsoid

Christophe Geuzaine cgeuzaine at ulg.ac.be
Sun Feb 2 22:36:21 CET 2014


On 29 Jan 2014, at 20:01, Nikolaus Rath <nrath at trialphaenergy.com> wrote:

> Hello,
> 
> Let me follow-up with another question right away:
> 
> I'm trying to create an ellipsoidal volume. From the docs, I gathered
> that I cannot extrude the surface by more than Pi, so I did it in 3
> steps of 2pi/3:
> 
> out[] = Extrude {{0, 0, 1}, {0,0,0}, 2*Pi/3} { Surface{1}; };
> out[] = Extrude {{0, 0, 1}, {0,0,0}, 2*Pi/3} { Surface{out[0]}; };
> out[] = Extrude {{0, 0, 1}, {0,0,0}, 2*Pi/3} { Surface{out[0]}; };
> 
> The resulting geometry looks correct at first sight, but if I create a
> 2-D mesh, I can see that the object has three internal surfaces that
> separates it into three parts rather than one big volume.
> 
> What do I have to do to create just one big volume?
> 

You could simply extrude the curve (instead of the surface), and create the volume afterwards.

But why is generating 3 volumes a problem? Just group the volume inside a single physical group and you should be ok.


> (Complete sample file attached).
> 
> 
> Thanks!
> -Nikolaus
> 
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-- 
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science 
http://www.montefiore.ulg.ac.be/~geuzaine