[Gmsh] Boolean Fragments. Créate 3d mesh from surfaces. Surface Loop creates aditional surfaces

Wed Feb 7 19:41:33 CET 2018

Use the latest automatic snapshot: it contains many improvements w.r.t. opencascade.

> On 7 Feb 2018, at 19:26, Jacob Abdelfatah Ndioubnane <jacoban90 at outlook.es> wrote:
> 
> Thank you for your answer. I tried your boolean fragments command and gets me in that line the following error:
>  
> Info    : Reading 'C:\Users\Jacob\Documents\Cube\Cube.geo'...
> Info    : Reading 'C:\Users\Jacob\Documents\Cube\Inlet.brep'...
> Info    : Done reading 'C:\Users\Jacob\Documents\Cube\Inlet.brep'
> Info    : Reading 'C:\Users\Jacob\Documents\Cube\Walls.brep'...
> Info    : Done reading 'C:\Users\Jacob\Documents\Cube\Walls.brep'
> Info    : Reading 'C:\Users\Jacob\Documents\Cube\Outlet.brep'...
> Info    : Done reading 'C:\Users\Jacob\Documents\Cube\Outlet.brep'
> Error   : 'C:\Users\Jacob\Documents\Cube\Cube.geo', line 7 : syntax error (:)
> Error   : 'C:\Users\Jacob\Documents\Cube\Cube.geo', line 7 : syntax error (;)
> Error   : 'C:\Users\Jacob\Documents\Cube\Cube.geo', line 7 : syntax error (})
> Info    : Done reading 'C:\Users\Jacob\Documents\Cube\Cube.geo'
> Info    : Writing 'C:\Users\Jacob\Documents\Cube\cube.log'...
>  
> Instead of that I proved to use BooleanFragments{ Surface{1:6}; Delete; }{ }, but when apply the Surface loop appears 6 more surfaces and the volumen is referenced to them.
>  
> <77EC94B488A34710A037994804FB02A5.png>
>  
> I also tried to use Geometry.OCCAutoFix = 0, and gets me the output:
>  
> Info    : Reading 'C:\Users\Jacob\Documents\Cube\Cube.geo'...
> Error   : Unknown number option 'Geometry.OCCAutoFix'
> Info    : Reading 'C:\Users\Jacob\Documents\Cube\Inlet.brep'...
> Info    : Done reading 'C:\Users\Jacob\Documents\Cube\Inlet.brep'
> Info    : Reading 'C:\Users\Jacob\Documents\Cube\Walls.brep'...
> Info    : Done reading 'C:\Users\Jacob\Documents\Cube\Walls.brep'
> Info    : Reading 'C:\Users\Jacob\Documents\Cube\Outlet.brep'...
> Info    : Done reading 'C:\Users\Jacob\Documents\Cube\Outlet.brep'
> Info    : Done reading 'C:\Users\Jacob\Documents\Cube\Cube.geo'
> Info    : Writing 'C:\Users\Jacob\Documents\Cube\Cube2.log'...
>  
> I attach the script what I used to do that.
>  
> Best Regards 
> Jacob
>  
> Enviado desde Correo <https://go.microsoft.com/fwlink/?LinkId=550986> para Windows 10
>  
> De: Christophe Geuzaine <mailto:cgeuzaine at uliege.be>
> Enviado: miércoles, 7 de febrero de 2018 17:21
> Para: Jacob Abdelfatah Ndioubnane <mailto:jacoban90 at outlook.es>
> CC: Christophe Geuzaine <mailto:cgeuzaine at ulg.ac.be>; gmsh at onelab.info <mailto:gmsh at onelab.info>; G. D. McBain <mailto:gdmcbain at protonmail.com>
> Asunto: Re: [Gmsh] Boolean Fragments. Créate 3d mesh from surfaces. Surface Loop creates aditional surfaces
>  
>  
> 
> 
> On 7 Feb 2018, at 09:07, Jacob Abdelfatah Ndioubnane <jacoban90 at outlook.es <mailto:jacoban90 at outlook.es>> wrote:
>  
> Is thiis would be related to the normals of the surfaces?. I noticed that the normals is oriented outward. So i tried to invert the normals but i cannt find a way to do this.
>  
>  
> This works fine here:
>  
> SetFactory("OpenCASCADE");
> Merge "Inlet.brep";
> Merge "Walls.brep";
> Merge "Outlet.brep";
> BooleanFragments{ Surface{:}; Delete; }{ }
> Surface Loop(1) = {1, 5, 2, 3, 6, 4};
> Volume(1) = {1};
> 
> 
> When the orientation of surfaces is inconsistent open cascade will by default automatically reorient the surfaces; unless you set Geomtry.OCCAutoFix = 0.
>  
> 
> 
> I attach a figure below.
>  
> Best Regards
> Jacob<02951EDB824840E597D871724BDD93AD.png>
>  
> Enviado desde Correo <https://go.microsoft.com/fwlink/?LinkId=550986> para Windows 10
>  
> De: Jacob Abdelfatah Ndioubnane <mailto:jacoban90 at outlook.es>
> Enviado: martes, 6 de febrero de 2018 22:36
> Para: Christophe Geuzaine <mailto:cgeuzaine at ulg.ac.be>; gmsh at onelab.info <mailto:gmsh at onelab.info>; gmsh-owner at onelab.info <mailto:gmsh-owner at onelab.info>; gmsh-request at ace20.montefiore.ulg.ac.be <mailto:gmsh-request at ace20.montefiore.ulg.ac.be>; G. D. McBain <mailto:gdmcbain at protonmail.com>
> Asunto: Boolean Fragments. Créate 3d mesh from surfaces. Surface Loop creates aditional surfaces
>  
> Hi gmsh users:
>  
> I’m trying to créate a 3d mesh of a cube from a merged 3d surfaces to apply physical groups easily. I applied the booleanFragments operator, and it removes the aditional edges and vértices. However, when I créate a Surface loop, automatically generates aditional surfaces(when i go to tools;vissibility;tree appears 12 surfaces) it creates a , and the volume is referenced to the dupplicate surfaces. Im able to créate both 2d and 3d meses, but when i export into freefem as .mesh or .msh is not loaded correctly. Is there any way to solve this problem.  I attach the .geo script below and also the .brep surfaces and the generated .mesh and .msh meses.
>  
> // Gmsh project created on Tue Feb 06 20:13:28 2018
> SetFactory("OpenCASCADE");
>  
> Merge "Inlet.brep";
> Merge "Walls.brep";
> Merge "Outlet.brep";
>  
> s() = Surface "*";
> BooleanFragments{ Surface{s(0)}; Delete; }{ Surface{s({0:#s()-1})}; Delete; }//+
>  
>  
>  
>  
> //+
> Surface Loop(1) = {1, 5, 2, 3, 6, 4};
>  
> Volume(1) = {1};
>  
> Thank you very much in advance.
>  
> Best Regards 
> Jacob
>  
> Enviado desde Correo <https://go.microsoft.com/fwlink/?LinkId=550986> para Windows 10
>  
>  
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>  
> — 
> Prof. Christophe Geuzaine
> University of Liege, Electrical Engineering and Computer Science 
> http://www.montefiore.ulg.ac.be/~geuzaine <http://www.montefiore.ulg.ac.be/~geuzaine>
> 
> Free software: http://gmsh.info | http://getdp.info | http://onelab.info
>  
>  
> <Dupplicate surfaces.PNG><Cube.geo>

— 
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

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