[Gmsh] Question about tetrahedron element generation with GMSH

Jean-Francois Remacle jean-francois.remacle at uclouvain.be
Wed Aug 25 22:40:31 CEST 2010


David is right, and sure maybe we should automatically optimize 3D  
delaunay meshes

JF

Le 25-août-10 à 20:53, David Colignon a écrit :

>
>
> On 25/08/10 19:12, 류은현 wrote:
>> Before asking, Thank you for your kind answer about my preivous  
>> question.
>>
>> It was so helpful to me.
>>
>> I am working on developing 3D FEM application related with  
>> neutronics problem.
>>
>> Following is my first question
>>
>> Today I made 3D domain, that has physical volumes. But I saw that  
>> the jacobian of certain element is zero.
>>
>> Because of a element that is consist of 4 nodes which are located  
>> on same plane!
>
>
> Hi,
>
> Did you try the Tools->Options->Mesh->Advanced->"Optimize quality of  
> tetrahedra" option ?
>
>>
>> Why does GMSH produce such a strange element? Does it due to my  
>> fault in making GMSH input?
>
>
> Impossible to answer without your .geo file ...
>
> regards,
>
> Dave
>
>
>
> --
> David Colignon, Ph.D.
> Collaborateur Logistique du F.R.S.-FNRS
> CÉCI - Consortium des Équipements de Calcul Intensif
> 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
> WWW:    http://hpc.montefiore.ulg.ac.be/
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>
>
>>
>> Of course, I can eliminate that element by giving certain condition  
>> to my code, it seems to be strange.
>>
>> Please tell me in detail, if the reason is related with my input.
>>
>> My second question is associated with defining volume. I understood  
>> that the orientation of surfaces which will
>>
>> constitute the volume should be consistent. But if we want to make  
>> a cube or hexahedron volume, the following order of
>>
>> surface index is OK? I mean that writing index(upper plane),  
>> index(lower plane), index(left plane),.... , not continuously.
>>
>> Please tell me in detail. Sorry for bothering you.
>>
>>
>>
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>
>
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------------------------------------------------------------------
Prof. Jean-Francois Remacle
Universite catholique de Louvain (UCL)
Ecole Polytechnique de Louvain (EPL) - Louvain School of Engineering
Institute of Mechanics, Materials and Civil Engineering (iMMC)
Center for Systems Engineering and Applied Mechanics (CESAME)
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