[Gmsh] Extruding a circle into a cylinder

[Christophe Geuzaine]

On 09 Sep 2013, at 17:33, "Sacconi, Andrea" <a.sacconi11 at imperial.ac.uk> wrote:

> Hi everybody,
> 
> I have a problem with the Extrude command.
> I would like to create a cylindrical mesh, but I need to generate a mesh only on the lateral surface of the cylinder. In other words, I don't want any elements on the two circles, top and bottom.
> 
> I wrote this:
> 
> lc = 0.5;
> Point(1) = {-1, 0, 0, lc};
> Point(2) = {0, -1, 0, lc};
> Point(3) = {1, 0, 0, lc};
> Point(4) = {0, 1, 0, lc};
> Point(5) = {0, 0, 0, lc};
> Circle(1) = {1, 5, 2};
> Circle(2) = {2, 5, 3};
> Circle(3) = {3, 5, 4};
> Circle(4) = {4, 5, 1};
> Line Loop(5) = {1, 2, 3, 4};
> 
> geoExtrude[] = Extrude {0, 0, 1} { Line{5}; };
> 
> but I don't get any extrusion. I see only the circle centred at (0, 0, 0) with radius 1.
> Is it possible to get the cylinder I need? How would you proceed?
> 

5 is not a line; it's a line loop: so you should do

geoExtrude[] = Extrude {0, 0, 1} { Line{1,2,3,4}; };

or

geoExtrude[] = Extrude {0, 0, 1} { Line{1:4}; };


> Thanks in advance for your help!
> 
> Andrea
> 
> __________________________________________________________
> 
> Andrea Sacconi
> PhD student, Applied Mathematics
> AMMP Section, Department of Mathematics, Imperial College London,
> London SW7 2AZ, UK
> a.sacconi11 at imperial.ac.uk
> 
> _______________________________________________
> gmsh mailing list
> gmsh at geuz.org
> http://www.geuz.org/mailman/listinfo/gmsh

-- 
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science 
http://www.montefiore.ulg.ac.be/~geuzaine