[Gmsh] Mesh problem with rotated volume

[Christophe Geuzaine]

svhb at telenet.be wrote:
> Hi,
> 
> I added the Geometry.ExactExtrusion=0; line at the very beginning of my geo file, but :
> 
> Error   : Unknown number option 'Geometry.ExactExtrusion'
> 
> 
> with the nightly build : 2.3.1-cvs-20090416 (windows version). The ExactExtrusion is not in the optionlist when asking to print out the 'Current Options" in the Help menu. 


Can you try again? (for some reason last night's build did not complete 
on Windows)


> 
> If I understand it right, the problem lies in the fact that the extrusions generate "Ruled" surfaces instead of "Plane" surfaces. Will it help to not use extrusions, but create all plane surfaces and a volume manually?
> 
> Another thing, the example sent in previous mail must be extended a bit like in included picture. When I rotate this, the mesh generator creates a self-intersecting mesh on the curved surfaces. 
> 
> 
> Stefaan.
> 
> 
> 
>> ----- Oorspronkelijk bericht -----
>> Van
> : Christophe Geuzaine [mailto:cgeuzaine at ulg.ac.be]
>> Verzonden
> : donderdag
> , april
>  16, 2009 01:42 PM
>> Aan
> : svhb at telenet.be
>> CC
> : gmsh at geuz.org
>> Onderwerp
> : Re: [Gmsh] Mesh problem with rotated volume
>> svhb at telenet.be wrote:
>>> Hi, 
>>>
>>> I have a simple example of an extruded volume with a hole. It works fine until I rotate the volume. When rotated, the mesh looks corrupted, the mesh stick out the volume. 
>>>
>>> See two jpg files, and the geo file included.
>>>
>> Hi - This is a known limitation of the "extrude" command in the old CAD
>> module: extruded entities cannot be safely geometrically transformed
>> because we use the exact extrusion formula to interpolate.
>>
>> With tomorrow's nightly snapshot you will be able to set
>>
>>   Geometry.ExactExtrusion=0;
>>
>> This will fix your problem (at the cost of losing the exact
>> interpolation for curved surfaces, which is not a problem in your case).
>>
>>
>>> Thanks
>>>
>>>
>>>
>>> ------------------------------------------------------------------------
>>>
>>> _______________________________________________
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>>> gmsh at geuz.org
>>> http://www.geuz.org/mailman/listinfo/gmsh
>>
>> -- 
>> Prof. Christophe Geuzaine
>> University of Liege, Electrical Engineering and Computer Science
>> http://www.montefiore.ulg.ac.be/~geuzaine
>>
>>
>>
>>
>>
>>
>> ------------------------------------------------------------------------
>>
>> _______________________________________________
>> gmsh mailing list
>> gmsh at geuz.org
>> http://www.geuz.org/mailman/listinfo/gmsh


-- 
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science
http://www.montefiore.ulg.ac.be/~geuzaine