[Gmsh] Unable to create 3D mesh

[Christophe Geuzaine]

> On 28 Feb 2017, at 22:33, Christophe Geuzaine <cgeuzaine at ulg.ac.be> wrote:
> 
> 
> See attached corrected file and comments therein. Basically:
> 
> 1) embedded lines/surfaces are not a substitute for correct topology! they are only provided to embed 0D/1D/2D meshes in 1D/2D/3D ones (not e.g. 1D in 1D, or 2D in 2D, or 3D in 3D)
> 
> 2) to do the intersections automatically you will want to use the new SetFactory("OpenCASCADE") mode in recent nightly builds, and the "BooleanFragments" operation. See gmsh/demos/boolean for examples (there is no official documentation yet).

PS : here's how your geometry could be defined using the new tools:

SetFactory("OpenCASCADE");
Mesh.CharacteristicLengthMin = 2;
Mesh.CharacteristicLengthMax = 2;
Block(1) = {0,0,0, 64,60,40};
Cylinder(2) = {2,0,3, 2,60,3, 1};
Cylinder(3) = {2,0,18, 2,60,18, 1};
Cylinder(4) = {62,32,40, 62,32,0, 1};
v() = BooleanFragments{ Volume{1}; Delete; }{ Volume{2,3,4}; Delete; };


> 
> 
> <fixed.geo>
> 
>> On 28 Feb 2017, at 18:54, adhitomo sulistyo <adhitomo1 at gmail.com> wrote:
>> 
>> Hi, I am trying to create a reservoir model with unstructured grids. The reservoir is box shaped, with two horizontal wells on one side, and one vertical well on the other side. The model is basically a box with three cylinders inside.
>> 
>> Initially I succeeded in creating the 3D mesh. However, later I found that the mesh from the cylinder and the box were different and intersecting with each other. Based on the information from the web, I need to embed the surfaces inside the volume.
>> 
>> After successfully embedding the surfaces, the 2D mesh looks good. There are no longer intersecting grids However, when I try to run the 3D mesh, it fails. I get the following error message:
>> 
>> Info    : Done meshing 2D (0.715054 s)
>> Info    : Meshing 3D...
>> Info    : Delaunay Meshing 4 volumes with 4 connected components
>> Info    : Meshing volume 227 (Delaunay)
>> Info    : 7174 points 36783 edges and 14324 faces in the initial mesh
>> Info    : Found void region
>> Info    : Found void region
>> Info    : Found void region
>> Info    : Found void region
>> Error   : No tetrahedra in region 227 0
>> Info    : 3D point insertion terminated (7204 points created):
>> Info    :  - 0 Delaunay cavities modified for star shapeness
>> Info    :  - 0 points could not be inserted
>> Info    :  - 0 tetrahedra created in 0.010615 sec. (0 tets/sec.)
>> Info    : Meshing volume 228 (Delaunay)
>> Info    : 155 points 592 edges and 280 faces in the initial mesh
>> Info    : Found region 228
>> Info    : 0 points created - Worst tet radius is 1.10375 (PTS removed 0 0)
>> Info    : 3D point insertion terminated (7185 points created):
>> Info    :  - 0 Delaunay cavities modified for star shapeness
>> Info    :  - 0 points could not be inserted
>> Info    :  - 308 tetrahedra created in 0.004804 sec. (64113 tets/sec.)
>> Info    : Meshing volume 229 (Delaunay)
>> 
>> I have also attached the gmsh file. 
>> 
>> Thank you for your help.
>> 
>> Kind regards,
>> Adhitomo
>> 
>> 
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> 
> -- 
> 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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-- 
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