[Gmsh] Joining two pipes

[Martin Vymazal]

Hi Dave,

  ok, thanks for the info.

  Best regards,

   Martin Vymazal

P.S. Do you have any idea what open source software might be able to  
edit stl geometry? Salome maybe?


Quoting David Colignon <David.Colignon at ulg.ac.be>:

>
> On 04/08/10 20:06, Martin Vymazal wrote:
>
>> Hello,
>>
>> I would like to ask if anyone has an idea how (if at all) to join  
>> two cylindrical surfaces in gmsh. I have an 'msh' file
>> after conversion from CAD data. The file contains 2 pipes which  
>> have the same axis but slightly different diameters, one
>> following after the other. There's a small gap between the end of  
>> the first pipe and the beginning of the second pipe
>> that I'd like to cover with a surface mesh, thus joining the two pipes.
>> I have a circle (elementary entity number 1), which is the 'outlet  
>> ring' of the first pipe and another circle
>> (elementary entity # 2) - 'inlet ring' of the second pipe.  
>> Moreover, there's a line number 3 joining one point of the
>> first circle with another point on the second circle. These three  
>> lines form sort of a 'conical outline' - I have 2
>> bases with slightly different radiuses and one surface line  
>> connecting them. I thought I could write this in my geo file
>> (after merging the mesh with the two pipes):
>>
>> l1 = newreg;
>> Line Loop(l1) = {1,2,3};
>> Ruled Surface(newreg) = {l1};
>>
>> Unfortunately, gmsh meshes only the surface defined by circle 1,  
>> instead of meshing the conical surface that I tried to
>> define.
>>
>> Could you please tell if what I'm trying to do is feasible? If so,  
>> do you have an idea how to do it?
>>
>
> Hi Martin,
>
> I am not sure that Gmsh is able to understand the topology of the  
> surface you want to create, especially with the line n°3 joining the  
> two circles... Moreover Gmsh doesn't like arc circles greater than  
> PI ...
>
> The best solution would be to divide each circle in two parts, and  
> having a second line joining the two half circles...
>
> Regards,
>
> Dave
>
>
>
>> Best regards,
>>
>> Martin Vymazal
>>
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>>
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