3D Meshing

Mesh generators, CAD programs, and other tools
Andres29
Posts: 6
Joined: 20 Aug 2014, 16:25
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Re: 3D Meshing

Post by Andres29 »

Hello Matthias,

Let me explain to you why those lines are not included in the volume. Those lines are the ones that are between one building and other, that is to say, when 2 buildings are joined by a commom wall with irregular surfaces. Those lines are underneath the roof and inside the building. Therefore, the mesh is gonna touch the roof and the walls of the each building, nothing inside them. Is that an error as well?

Kind Regards,

Andres
mzenker
Posts: 1999
Joined: 07 Dec 2009, 11:49
Location: Germany

Re: 3D Meshing

Post by mzenker »

Hi,

all I can say is that each object not logically included in your volume, but physically being located inside or adjacent (=touching it) will lead to an overlapping mesh which will generate to an error. gmsh meshes everything there is, but cannot resolve overlapping meshes. So if you have a line inside the volume, it will try calculate one mesh for the line and one mesh for the volume which are independent of each other. The nodes will be at different locations. It will then detect two overlapping meshes and spit error messages.
So IMO the only way to proceed is to build your volume so that every object is contained in it (exception made for points, perhaps, e.g. the center of a circle or arc).
BTW you can see where the errors occur by merging the intersect.pos file written by gmsh to your geometry.

HTH,

Matthias

P.S.: I will now be off for a week... ;)
jesusnv
Posts: 7
Joined: 24 Sep 2014, 10:50
Antispam: Yes

Re: 3D Meshing

Post by jesusnv »

Hello;

I want to know which geometry files can load to gmsh??? Maybe autocad files or similar. I tried with .stl files and I only saw the mesh, I couldn´t saw the points, lines, surfaces etc... What its the problem?

can someone help me???

thanks and have a nice day
mzenker
Posts: 1999
Joined: 07 Dec 2009, 11:49
Location: Germany

Re: 3D Meshing

Post by mzenker »

Hi,

gmsh can load STEP files, AFAIR also IGES and BREP. I don't think it can load autocad files. Please refer to the documentation on the gmsh website (http://www.geuz.org/gmsh). The gmsh mailing list is the right place for more detailed questions.

HTH,

Matthias
jesusnv
Posts: 7
Joined: 24 Sep 2014, 10:50
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Re: 3D Meshing

Post by jesusnv »

Sorry by writting in different posts, I was not sure that anybody was answering myself and I wrote in diferent posts.

Thanks for your post, I am going to try with the formats that you have said to me. When it exports the geometries there is some option that it has to select?

thanks
mzenker
Posts: 1999
Joined: 07 Dec 2009, 11:49
Location: Germany

Re: 3D Meshing

Post by mzenker »

Hi,

I don't know what you have to select in your CAD when you export the geometry. When you export the mesh from gmsh, you should either define physical groups containing the entities you want to export, or select "export all" in the dialog box which pops up at export.

HTH,

Matthias
jesusnv
Posts: 7
Joined: 24 Sep 2014, 10:50
Antispam: Yes

Re: 3D Meshing

Post by jesusnv »

Hello :)

When I open mi stl file with gmsh, I only see the mesh surface, Can I see the elements of geometry? the points, lines, surfaces etc... .

Thanks
mzenker
Posts: 1999
Joined: 07 Dec 2009, 11:49
Location: Germany

Re: 3D Meshing

Post by mzenker »

Tools->Visibility
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