[Gmsh] entity numbering

[Christophe Geuzaine]

quemener at isn.in2p3.fr wrote:
> 
> Hello,
> 
> I have just started looking through the tutorial examples for GMSH, but
> I have some troubles understanding how the numbering of the generated
> entities is performed. For Instance in the file t2.geo:
> 
> 1) Does the command "Translate {-0.05,0,0} { Point(3) ; }" generate a
> point numbered by 6
> and  "Translate {-0.05,0,0} { Duplicata{Point(3) ; } }" a point numbered
> by 7?  Or only the
> "Duplicata" command creates a new point (6 in fact) and the "simple
> Translate" command
> only move an existing point without creating a new one?

Yes, that's it: the first 'Translate' does not create a point (it only
moves the point 3 around). The second creates a duplicata (a copy), with
a new number (equal to 'newp', i.e. the highest point number, plus 1).

> 
> 2) I suppose that the extrusion process creates some new points (with
> assigned numbers), but how is performed the numbering for points 22, 16
> and 12 mentioned in the command:
> Characteristic Length{6,22,2,3,16,12}? From which points are they
> extruded?

The extrusion automatically creates some new points. Guessing their
numbers is hard (duplicates are suppressed, etc.): the 'Characteristic
Length{6,22,2,3,16,12}' command was indeed generated interactively, by
selecting the points with the mouse.

> 
> 3) Similar questions for the surfaces numbered 121, 131, 135, 139, 144,
> I suppose that they come from the extrusion process, but how their
> numbering was decided and to which points(number) are they linked?

Same as above... You may either get the info interactively, or ask gmsh
to flatten the geometry with 'gmsh t2 -0'.


Christophe

-- 
Christophe Geuzaine

Tel: 32 (0) 4 366 37 10    http://geuz.org
Fax: 32 (0) 4 366 29 10    mailto:Christophe.Geuzaine at ulg.ac.be