# [Gmsh] Message receive it on messages window ....

Christophe Geuzaine geuzaine at acm.caltech.edu
Wed May 28 05:52:19 CEST 2003

```Catalin Bondrea wrote:
> Dear GMSH users,
> In the last time I don't work with GMSH program, but since today (27 May 2003) I come back to finish an old problem.
>
> This it was the answer for my last request:
> "
> Catalin - did you check tutorial/t5.geo? The usual way to create a
> volume with holes in gmsh is to
>
> - define the surface loops for the holes
> - define the exterior surface loop
> - define the exterior volume (the air) as a list of these surface loops,
> the first one being the exterior loop
> "
> Notations:
> i* means that is a point, when i is a number indicating the number of the point.
> i means the volume number
>
> Fig.1							Fig.2
> 	|----------------|					1*|----------------|*7
> 	|   |----|       |					  |   3*|----|*5   |
> 	|   |  2 |       |					  |     |  2 |     |
> 	|   |    |       |					  |     |    |     |
> 	|   |----|       |					  |   4*|----|*6   |
> 	|  1             |					  |  1             |
> 	|----------------|					2*|----------------|*8
>
> Fig.3
> 	|----------------|
> 	| 		 |
> 	|----|		 |
> 	|  4 | 		 |
> 	|    |      	 |
> 	|----|       	 |
> 	|       3        |
> 	|		 |
> 	|----------------|
>
> 	We have two figures:
> 		In fig.1 we have two volumes 1 and 2
> 		In fig.2 we have two volumes 3 and 4
> 	If we try to do this in gmsh, in fig.2 it's more or less easy to implement. We have like in fig.2 8 points.
> 	What we do when we want to draw the fig.3. The problem is with sharing one lines, that means when we want to draw
> 	the fig.3 we need to modify in this way:
> Fig.4
> 	1*|--------------|*7
>  	  | 		 |
> 	2*|----|*5 	 |
> 	  |  4 | 	 |
> 	  |    |      	 |
> 	3*|----|*6    	 |
> 	  |       3      |
> 	  |		 |
> 	4*|--------------|*8
>
> 	From point 2* to 1* in fig.2 is one line.
> 	From point 4* to 1* in fig.4 we have 3 lines.
> 	And the line between 3* to 2* is a line with appear in volume 3 and also in volume 4.
>
> 	More or less I have one more complicated geo file for what I want to draw.
> 	If I create the bigger volume like in fig 2 I DON'T HAVE PROBLEMS.
> 	if I try like in fig.4 I have problems like: Warning: Volumes has changed (some numbers -> some numbers)
> 	and like don't want to finish showing all this messages.
>
> 	The question: What is to do in this case?
>

In that case the topology is different: you *don't* have any holes
anymore. The first surface is simply defined by the lines joining the
points 1,2,5,6,3,4,8,7 and the second surface by the lines joining the
points 2,3,6,5...

Christophe

--
Christophe Geuzaine

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

```