[Gmsh] Getting Surfaces and Volumes per coordinates after importing a step file

[David Colignon]

On 29/07/17 13:28, faber.mueller at t-online.de wrote:

> Dear Professor Geuzaine,
> 
> I want to show my group at my working place, that the combination of gmsh and getdp is at least as powerful as an commercial FEA Software or 
> even more powerful. For that purpose I have imported a model of an Claw Pole Alternator as a step file into gmsh. That worked very well and it 
> is no problem to pick the faces and volumes with the gui. But because of the fact that I have imported the geometry I have no information about 
> the elementary entities in the geo file. So I can't change the characteristic lengths individually for the interesting lines/points.
> 
> Is it possible to get for example the volume or a surface with a command like 'get volume at point (x,y,z)' ? That would be awesome to automate 
> the picking of the areas and volumes for defining the physical entities.
> 
> Is there a function / command to get the surfaces that define a volume  or the lines that define an area? The problem is that the geometry is 
> very complicated and I need to define the elements for every volume or area seperately to get a fine mesh in the airgap and a coarse mesh in the 
> outer air and so on.

Hi,

Here it is:

http://gmsh.info/doc/texinfo/gmsh.html#Transformations

Boundary { transform-list }

     (Not a transformation per-se.) Returns the entities on the boundary of the elementary entities in transform-list, with signs indicating 
their orientation in the boundary. To get unsigned tags (e.g. to reuse the output in other commands), apply the Abs function on the returned list.

Regards,

Dave

-- 
David Colignon, Ph.D.
1er Logisticien de Recherche
Université de Liège
ACE - Applied & Computational Electromagnetics
Quartier POLYTECH 1 - Montefiore B28
Allée de la découverte 10
4000 Liège - BELGIQUE
Tél: +32 (0)4 366 37 32
http://www.ulg.ac.be/nic4

> 
> Is there a way to combine several fields for every volume to one field and set it as the background field?
> 
> Sorry for so many questions and thanks for your time reading this.
> 
> Best regards
> 
> Fabian Müller
> 
> 
> 
> 
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