[Gmsh] How to make a hole in a volume?

[Christophe Geuzaine]

"Toshiro K. Ohsumi" wrote:
> 
> Hello,
> 
>     I would like to put a hole in a volume, something like the magnetron in
> the Gmsh gallery.  Unfortunately, it is not exactly clear from the tutorial
> how to do this, either in a *.geom file or by the GUI.  (In the latter, I am
> not sure how the hole specification works.)  I have created the points and
> lines, as attached below.  What I need is the top and bottom surface (the area
> between the concentric surfaces), the four sizes, and the volume between the
> outer walls and the inner walls.  Any tips on how to do this (e.g. an example
> *.geom file) would be much appreciated.  Many thanks,
> 

cf. tutorial/t5.geo

The easiest way to generate such geometries is to use the GUI : to
define a volume, you first select the exterior boundary, then gmsh will
ask you to select the boundary of any holes in the volume. Beware that
the boundary of the hole must be disjoint from the exterior boundary.
Otherwise it's not a hole anymore (gmsh would try to mesh the
zero-volume area), and you need simply to define two regular volumes,
having the surface(s) in common.

Christophe

-- 
Christophe Geuzaine

Tel: (626) 395-4552    http://www.geuz.org
Fax: (626) 578-0124    mailto:geuzaine at acm.caltech.edu