[Gmsh] Swiss cheese with filled cavities

Fri Mar 31 08:59:57 CEST 2017

Dear Achille,

As is, your script is already meshing the hole/inclusion volumes. Do you wish to produce two mesh files, one with the "cheese" mesh and the other with the inclusion mesh ? If that is the case, you can comment out the line Physical Volume (t) = thehole ; run the model once, save the mesh, this will give you the "cheese" mesh. Then uncomment that line and comment out Physical Volume (10) = 100 ; and you should get the inclusions only.

Faithfully yours,

Guillaume DILASSER
Doctorant SACM / LEAS
CEA - Centre de Saclay - Bât.123 - PC 319c
91191 Gif sur Yvette Cedex - France -

guillaume.dilasser at cea.fr<mailto:guillaume.dilasser at cea.fr>

-----Message d'origine-----
De : gmsh [mailto:gmsh-bounces at ace20.montefiore.ulg.ac.be] De la part de Achille Pluplu
Envoyé : jeudi 30 mars 2017 18:44
À : gmsh at onelab.info
Objet : [Gmsh] Swiss cheese with filled cavities

Dear all,

I'm quite new to GMSH so, please, be patient.

I need to create a 3D mesh of a cube that include some inclusions

(spheres) of a different material.

I could find the following script that generates a cube with 5 cavities, but how can I mesh also the inclusions? In particular I need two well separated meshes, one for the "cheese" the other for the inclusions

Thanks a lot for helping!

Function CheeseHole

   // In the following commands we use the reserved variable name

   // `newp', which automatically selects a new point number. This

   // number is chosen as the highest current point number, plus

   // one. (Note that, analogously to `newp', the variables `newc',

   // `news', `newv' and `newreg' select the highest number amongst

   // currently defined curves, surfaces, volumes and `any entities

   // other than points', respectively.)

   p1 = newp; Point(p1) = {x,  y,  z,  lcar3} ;

   p2 = newp; Point(p2) = {x+r,y,  z,  lcar3} ;

   p3 = newp; Point(p3) = {x,  y+r,z,  lcar3} ;

   p4 = newp; Point(p4) = {x,  y,  z+r,lcar3} ;

   p5 = newp; Point(p5) = {x-r,y,  z,  lcar3} ;

   p6 = newp; Point(p6) = {x,  y-r,z,  lcar3} ;

   p7 = newp; Point(p7) = {x,  y,  z-r,lcar3} ;

   c1 = newreg; Circle(c1) = {p2,p1,p7};

   c2 = newreg; Circle(c2) = {p7,p1,p5};

   c3 = newreg; Circle(c3) = {p5,p1,p4};

   c4 = newreg; Circle(c4) = {p4,p1,p2};

   c5 = newreg; Circle(c5) = {p2,p1,p3};

   c6 = newreg; Circle(c6) = {p3,p1,p5};

   c7 = newreg; Circle(c7) = {p5,p1,p6};

   c8 = newreg; Circle(c8) = {p6,p1,p2};

   c9 = newreg; Circle(c9) = {p7,p1,p3};

   c10 = newreg; Circle(c10) = {p3,p1,p4};

   c11 = newreg; Circle(c11) = {p4,p1,p6};

   c12 = newreg; Circle(c12) = {p6,p1,p7};

   // We need non-plane surfaces to define the spherical holes. Here we

   // use ruled surfaces, which can have 3 or 4 sides:

   l1 = newreg; Line Loop(l1) = {c5,c10,c4};   Ruled Surface(newreg) = {l1};

   l2 = newreg; Line Loop(l2) = {c9,-c5,c1};   Ruled Surface(newreg) = {l2};

   l3 = newreg; Line Loop(l3) = {c12,-c8,-c1}; Ruled Surface(newreg) = {l3};

   l4 = newreg; Line Loop(l4) = {c8,-c4,c11};  Ruled Surface(newreg) = {l4};

   l5 = newreg; Line Loop(l5) = {-c10,c6,c3};  Ruled Surface(newreg) = {l5};

   l6 = newreg; Line Loop(l6) = {-c11,-c3,c7}; Ruled Surface(newreg) = {l6};

   l7 = newreg; Line Loop(l7) = {-c2,-c7,-c12};Ruled Surface(newreg) = {l7};

   l8 = newreg; Line Loop(l8) = {-c6,-c9,c2};  Ruled Surface(newreg) = {l8};

   // We then store the surface loops identification numbers in a list

   // for later reference (we will need these to define the final

   // volume):

   theloops[t] = newreg ;

   Surface Loop(theloops[t]) = {l8+1,l5+1,l1+1,l2+1,l3+1,l7+1,l6+1,l4+1};

   thehole = newreg ;

   Volume(thehole) = theloops[t] ;

Return

lcar3 = .055;

hloc = 0.1;

Point(1) = {0, 0, 0, hloc};

Point(2) = {1, 0, 0, hloc};

Point(3) = {1, 1, 0, hloc};

Point(4) = {0, 1, 0, hloc};

Point(5) = {0, 0, 1, hloc};

Point(6) = {1, 0, 1, hloc};

Point(7) = {1, 1, 1, hloc};

Point(8) = {0, 1, 1, hloc};

Line(1) = {1,2};

Line(2) = {2,3};

Line(3) = {3,4};

Line(4) = {4,1};

Line(5) = {5,6};

Line(6) = {6,7};

Line(7) = {7,8};

Line(8) = {8,5};

Line(9)  = {1,5};

Line(10) = {2,6};

Line(11) = {3,7};

Line(12) = {4,8};

// bottom

Line Loop(21) = {-1,-4,-3,-2};

Plane Surface(31) = {21} ;

// top

Line Loop(22) = {5,6,7,8};

Plane Surface(32) = {22} ;

// left

Line Loop(23) = {1,10,-5,-9};

Plane Surface(33) = {23} ;

// right

Line Loop(24) = {12,-7,-11,3};

Plane Surface(34) = {24} ;

// front

Line Loop(25) = {2,11,-6,-10};

Plane Surface(35) = {25} ;

// back

Line Loop(26) = {9,-8,-12,4};

Plane Surface(36) = {26} ;

// We can use a `For' loop to generate five holes in the cube:

x = 0 ; y = 0.75 ; z = 0 ; r = 0.09 ;

For t In {1:5}

   x += 0.166 ;

   z += 0.166 ;

   // We call the `CheeseHole' function:

   Call CheeseHole ;

   // We define a physical volume for each hole:

   Physical Volume (t) = thehole ;

   // We also print some variables on the terminal (note that, since

   // all variables are treated internally as floating point numbers,

   // the format string should only contain valid floating point format

   // specifiers like `%g', `%f', '%e', etc.):

   Printf("Hole %g (center = {%g,%g,%g}, radius = %g) has number %g!", t, x, y, z, r, thehole) ;

EndFor

theloops[0] = newreg ;

Surface Loop(theloops[0]) = {31,32,33,34,35,36};

Volume(100) = {theloops[]};

Physical Volume (10) = 100 ;

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