[Gmsh] gmsh: bug report

[David Colignon]

OK, I got the point, and you are right, this is a bug in our Delaunay-tetgen algorithm.
You already have found the first solution: to use netgen.
Another solution is to define the external volume and not saving it (no definition of Physical Volume)

Cheers,

Dave

-- 
David Colignon, Ph.D.
ACE - Applied & Computational Electromagnetics
Institut Montefiore B28
Université de Liège
4000 Liège - BELGIQUE
Tél: +32 (0)4 366 37 32
Fax: +32 (0)4 366 29 10
http://elap.montefiore.ulg.ac.be


daniela.wulf at arcor.de wrote:
> After meshing the geometry I had a look at the mesh with the surface faces (Options->mesh->Visibility->Surface faces). The surface triangles belonging to the tetrahedrons (pane) are not connected to the triangle at the frame. Have a look at the boundary layer. There are "hanging nodes".
> 
> Daniela
> 
> 
> ----- Original Nachricht ----
> Von:     David Colignon <David.Colignon at ulg.ac.be>
> An:      daniela.wulf at arcor.de
> Datum:   12.11.2007 10:30
> Betreff: Re: Aw: Re: Aw: Re: [Gmsh] gmsh: bug report
> 
>> I'm sorry but I don't understand your problem related to "non connected
>> triangles". I can mesh your file window.geo with 
>> the two 3D meshing algorithmes, without any problem...
>>
>> Dave
>>
>>
>> -- 
>> David Colignon, Ph.D.
>> ACE - Applied & Computational Electromagnetics
>> Institut Montefiore B28
>> Université de Liège
>> 4000 Liège - BELGIQUE
>> Tél: +32 (0)4 366 37 32
>> Fax: +32 (0)4 366 29 10
>> http://elap.montefiore.ulg.ac.be
>>
>>
>> daniela.wulf at arcor.de wrote:
>>> Hello,
>>>
>>> yes, it works very, very well! In this case it was my mistake! I have used
>> a tool to test the direction of the normal vector in a wrong way. I feel
>> very bad about that! Sorry!
>>> Therefore, there are only the not connected tetrahedrons and triangles for
>> the other mesh, where I had to change the 3D mesh algorithm. Netgen works
>> well while Tetgen + Delaunay produces not connected triangles. The file is
>> attached.
>>> Please excuse my mistake!
>>>
>>> Daniela
>>>
>>>
>>> ----- Original Nachricht ----
>>> Von:     David Colignon <David.Colignon at ulg.ac.be>
>>> An:      daniela.wulf at arcor.de
>>> Datum:   12.11.2007 08:38
>>> Betreff: Re: Aw: Re: [Gmsh] gmsh: bug report
>>>
>>>> Hi,
>>>>
>>>> the attached .geo file works very well. Can you send us a .geo files
>> which
>>>> doesn't work ?
>>>>
>>>> Also, the definition of Physical entities has no impact on the meshing,
>> it
>>>> is just a way to tag meshed entities in the 
>>>> .msh file and to decide which entities are saved in the .msh file.
>>>>
>>>> Cheers,
>>>>
>>>> Dave
>>>>
>>>> -- 
>>>> David Colignon, Ph.D.
>>>> ACE - Applied & Computational Electromagnetics
>>>> Institut Montefiore B28
>>>> Université de Liège
>>>> 4000 Liège - BELGIQUE
>>>> Tél: +32 (0)4 366 37 32
>>>> Fax: +32 (0)4 366 29 10
>>>> http://elap.montefiore.ulg.ac.be
>>>>
>>>>
>>>> daniela.wulf at arcor.de wrote:
>>>>> Oh! I'm sorry!
>>>>>
>>>>> But now it is attached!
>>>>>
>>>>> Daniela
>>>>>
>>>>>
>>>>> ----- Original Nachricht ----
>>>>> Von:     David Colignon <David.Colignon at ulg.ac.be>
>>>>> An:      daniela.wulf at arcor.de
>>>>> Datum:   09.11.2007 15:43
>>>>> Betreff: Re: [Gmsh] gmsh: bug report
>>>>>
>>>>>> daniela.wulf at arcor.de wrote:
>>>>>>> Dear ladies and gentlemen,
>>>>>>>
>>>>>>> I think there is a problem combining tetrahedrons and triangles:  I
>>>> wanted
>>>>>> to discretize a kind of "window". The  pane has to be discretized by
>>>>>> tetrahedrons. The frame is made up by a thin sheet. Therefore, I said
>>>> the
>>>>>> small side surfaces to be Physical Surfaces.  The Volume (the pane) is
>>>>>> defined physical as well. The mesh generated by gmsh contains
>> triangles
>>>> that
>>>>>> are not connected. In this case even a triangle that is completely
>> free
>>>>>> occurs. Meshing only the frame (by not saying the volume to be
>> physical)
>>>>>> yield a nice and connected mesh. I have already tried to use both
>>>>>> 3d-algorithms.
>>>>>>> I have attached the geo-file to this email.
>>>>>> Are you sure ?
>>>>>>
>>>>>> Dave
>>>>>>
>>>>>>
>>>>>>> Also some days ago, I had to change the 3d mesh algorithm to receive
>> a
>>>>>> connected mesh for a similar object. (The frame was modeled as volume
>>>>>> instead of a sheet.) Here, the triangles were not connected to the
>>>>>> tetrahedron. But they were connected using the other 3d-algorithm.
>>>>>>> Kind regards,
>>>>>>>
>>>>>>> Daniela Wulf
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> gmsh mailing list
>>>>>>> gmsh at geuz.org
>>>>>>> http://www.geuz.org/mailman/listinfo/gmsh