[Gmsh] creating patch on sphere

[Max Orok]

Hi Peter,

Scripts are always helpful! It is nice to be able to see the steps as you
go along.

Max

On Wed, Apr 24, 2019 at 8:36 AM Peter Johnston <p.johnston at griffith.edu.au>
wrote:

> Hello,
>
> I appear to have a problem for which I cannot figure out a solution.
>
> I have an annular hemispherical volume created between to hemispheres
> centred on the origin. I would like to divide the volume into two parts in
> a special way using Boolean operations. To define a sub-volume of the
> initial volume by defining four points on the surface of the inner sphere,
> create a “quadrilateral” on the inner surface by joining the four points in
> order using circles through the origin. (I think that these should be parts
> of great circles on the inner surface?). Then I create a line loop and a
> surface, and finally extrude the surface away from the origin to create a
> volume. Perhaps a .geo script would help here?
>
> When I perform BooleanDifferences and BooleanIntersections I end up with
> three volumes instead of two. The reason I get the third volume is that the
> surface patch that I create does not fit exactly onto the original
> spherical surface. Is there any way that I can force the patch to be part
> of the spherical surface?
>
> A consequence of the extra volume is that I cannot create a sensible mesh.
>
> Any ideas would be greatly appreciated.
>
> Thanks very much,
>
> Peter.
>
> PS, I could send a simple script file if that would help.
>
> ---------------------------------------------------------------------
>
> Associate Professor Peter Johnston (FAustMS, FIMA)
> School of Environment and Science
> Griffith University | Nathan | QLD 4111 | Technology (N44) Room 3.19
> T +61 7 373 57748| F +61 7 373 57656 Email p.johnston at griffith.edu.au
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>


-- 
Max Orok
Contractor
www.mevex.com
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