[Gmsh] EXTERNAL: Re: Embedded Mesh
Jensen, Aaron J.
Aaron.J.Jensen at leidos.com
Tue Dec 11 20:49:41 CET 2018
Thank you for adding pyramid support in version 4.0.5! It's been a huge help for building hybrid meshes.
A possible feature would be the ability to export the unstructured and structured part of the mesh as two separate files. One file containing the structured mesh (plot3d) and the other containing the unstructured mesh.
Thanks again,
Aaron
-----Original Message-----
From: cgeuzaine at uliege.be [mailto:cgeuzaine at uliege.be]
Sent: Friday, October 12, 2018 11:49 AM
To: Jensen, Aaron J. [US-US]
Cc: gmsh at onelab.info
Subject: Re: [Gmsh] EXTERNAL: Re: Embedded Mesh
> On 12 Oct 2018, at 17:12, Jensen, Aaron J. <Aaron.J.Jensen at leidos.com> wrote:
>
> If I made a single layer of pyramids (via external script) on the quad boundary could I trick gmsh into using that as the boundary if I properly defined it in a *.msh file?
Yes, that would work.
> I can figure out how to do it, I just want to make sure it's possible before I spend too Mach time on it.
>
> Thanks,
> Aaron
>
> -----Original Message-----
> From: Christophe Geuzaine [mailto:cgeuzaine at uliege.be]
> Sent: Friday, October 12, 2018 1:16 AM
> To: Jensen, Aaron J. [US-US]
> Cc: gmsh at onelab.info
> Subject: Re: EXTERNAL: Re: [Gmsh] Embedded Mesh
>
>
>
>> On 12 Oct 2018, at 00:56, Jensen, Aaron J. <Aaron.J.Jensen at leidos.com> wrote:
>>
>> Hopefully this will be the last question for a while...
>>
>> I am trying the same thing in 3D now. I am having a similar problem where I am not generating 3D elements in this case. I have attached the files.
>
> The boundary meshes should be triangular. Gmsh does not (yet) support generating automatic 3D tetrahedral+pyramidal meshes with quads on boundaries.
>
>>
>> Thanks in advance,
>> Aaron
>>
>> -----Original Message-----
>> From: Jensen, Aaron J. [US-US]
>> Sent: Thursday, October 11, 2018 4:11 PM
>> To: 'Christophe Geuzaine'
>> Cc: gmsh at onelab.info
>> Subject: RE: EXTERNAL: Re: [Gmsh] Embedded Mesh
>>
>> I can't tell you how much I appreciate the help! Thank you!
>>
>> -----Original Message-----
>> From: Christophe Geuzaine [mailto:cgeuzaine at uliege.be]
>> Sent: Thursday, October 11, 2018 3:29 PM
>> To: Jensen, Aaron J. [US-US]
>> Cc: gmsh at onelab.info
>> Subject: Re: EXTERNAL: Re: [Gmsh] Embedded Mesh
>>
>>
>> Here we go:
>>
>> Merge "square";
>>
>> Line Loop(1) = {1,2,3,4}; // fixed
>>
>> squareWidth = 1.5;
>> halfSquareWidth = squareWidth/2.0;
>>
>> lc = 0.3;
>> Point(1001) = {-halfSquareWidth,-halfSquareWidth,0.0,lc};
>> Point(1002) = {-halfSquareWidth, halfSquareWidth,0.0,lc};
>> Point(1003) = { halfSquareWidth, halfSquareWidth,0.0,lc};
>> Point(1004) = { halfSquareWidth,-halfSquareWidth,0.0,lc};
>> Line(1001) = {1004,1003};
>> Line(1002) = {1003,1002};
>> Line(1003) = {1002,1001};
>> Line(1004) = {1001,1004};
>>
>> Line Loop(1005) = {1002,1003,1004,1001};
>>
>> Plane Surface(1006) = {1005, 1}; // fixed
>>
>>
>>
>>> On 11 Oct 2018, at 19:25, Jensen, Aaron J. <Aaron.J.Jensen at leidos.com> wrote:
>>>
>>> Christophe,
>>>
>>> Thank you for the fast response. The latest snapshot works great and fixes the crash.
>>>
>>> I am still setting up the problem incorrectly. Here is what I have now:
>>>
>>>
>>> Merge "square";
>>> Line Loop(1) = {1};
>>>
>>> squareWidth = 1.5;
>>> halfSquareWidth = squareWidth/2.0;
>>>
>>> lc = 0.3;
>>> Point(1001) = {-halfSquareWidth,-halfSquareWidth,0.0,lc};
>>> Point(1002) = {-halfSquareWidth, halfSquareWidth,0.0,lc};
>>> Point(1003) = { halfSquareWidth, halfSquareWidth,0.0,lc};
>>> Point(1004) = { halfSquareWidth,-halfSquareWidth,0.0,lc};
>>> Line(1001) = {1004,1003};
>>> Line(1002) = {1003,1002};
>>> Line(1003) = {1002,1001};
>>> Line(1004) = {1001,1004};
>>>
>>> Line Loop(1005) = {1002,1003,1004,1001};
>>>
>>> Surface Loop(1006) = {1005, 1};
>>>
>>>
>>> I think it is close to working but I get the warning message: "1D mesh not forming a closed loop".
>>>
>>> Any help would be greatly appreciated.
>>>
>>> Thanks,
>>> Aaron
>>>
>>> -----Original Message-----
>>> From: Christophe Geuzaine [mailto:cgeuzaine at uliege.be]
>>> Sent: Thursday, October 11, 2018 8:11 AM
>>> To: Jensen, Aaron J. [US-US]
>>> Cc: gmsh at onelab.info
>>> Subject: EXTERNAL: Re: [Gmsh] Embedded Mesh
>>>
>>>
>>>
>>>> On 10 Oct 2018, at 21:12, Jensen, Aaron J. <Aaron.J.Jensen at leidos.com> wrote:
>>>>
>>>> Hello,
>>>>
>>>> I would like to merge an existing mesh into a geometry and then mesh the unmeshed region using gmsh (something like a boundary mesh around a pre-existing mesh generated externally by another program). Ideally, this would result in a mesh that was partially created in gmsh and partially created externally to gmsh. Ultimately, I would like to do this in both 2D and 3D but am starting with the following in 2D:
>>>>
>>>>
>>>>
>>>> Merge "square";
>>>>
>>>> SetFactory("OpenCASCADE");
>>>>
>>>> Surface Loop(1) = {1};
>>>> //sExternal = news;
>>>> //Rectangle(sExternal) = {0, 0, 0.0, 0.5, 0.5};
>>>>
>>>> s1 = news;
>>>> Rectangle(s1) = {-0.25, -0.25, 0.0, 1.0, 1.0};
>>>>
>>>> //BooleanDifference (2000) = { Surface{s1}; Delete; }{ Surface{sExternal}; };
>>>> BooleanDifference (2000) = { Surface{s1}; Delete; }{ Surface{1}; };
>>>>
>>>
>>> This cannot work: boolean operations can only be applied to CAD entities. It should not crash though - and it does not on my machine. Can you try with the latest snapshot?
>>>
>>> You can still produce a mesh like the one you want. With the built-in engine, simply
>>>
>>> - load the mesh, which should contain the bounding surface mesh
>>>
>>> - define the exterior "Surface Loop" where the interior surfaces are the bounding surfaces (discrete)
>>>
>>> Christophe
>>>
>>>
>>>>
>>>>
>>>> OpenCascade doesn’t recognize surface 1 and BooleanDifference causes gmsh to crash. I assume I am doing something wrong? Can gmsh embed an existing mesh into a gmsh geometry or CAD model?
>>>>
>>>> Thanks,
>>>> Aaron
>>>> <square>_______________________________________________
>>>> gmsh mailing list
>>>> gmsh at onelab.info
>>>> http://onelab.info/mailman/listinfo/gmsh
>>>
>>> —
>>> Prof. Christophe Geuzaine
>>> University of Liege, Electrical Engineering and Computer Science
>>> http://www.montefiore.ulg.ac.be/~geuzaine
>>>
>>> Free software: http://gmsh.info | http://getdp.info | http://onelab.info
>>>
>>
>> —
>> Prof. Christophe Geuzaine
>> University of Liege, Electrical Engineering and Computer Science
>> http://www.montefiore.ulg.ac.be/~geuzaine
>>
>> Free software: http://gmsh.info | http://getdp.info | http://onelab.info
>>
>> <Combined3D.GEO><cube>
>
> —
> Prof. Christophe Geuzaine
> University of Liege, Electrical Engineering and Computer Science
> http://www.montefiore.ulg.ac.be/~geuzaine
>
> Free software: http://gmsh.info | http://getdp.info | http://onelab.info
>
> _______________________________________________
> gmsh mailing list
> gmsh at onelab.info
> http://onelab.info/mailman/listinfo/gmsh
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