[Gmsh] Line loop and Open cascade

Thu Feb 22 17:32:06 CET 2018

Is it possible to extract associated line loop with each rectangle command so that I can define a plane surface with line loops that forms holes of first ones ?

________________________________
Best Regards,

Sathyanarayan Rao, PhD student
Earth and Life Institute/Environmental Sciences (ELI-e)
Université catholique de Louvain
c.037, Croix du Sud 2, Louvain-la-Neuve, Belgium
Phone: 010473827 ( intercom 73827)

________________________________

________________________________
From: Christophe Geuzaine <cgeuzaine at uliege.be>
Sent: 22 February 2018 17:25:27
To: Sathyanarayan Rao
Cc: gmsh at onelab.info
Subject: Re: [Gmsh] Line loop and Open cascade

On 22 Feb 2018, at 16:47, Sathyanarayan Rao <sathyanarayan.rao at uclouvain.be<mailto:sathyanarayan.rao at uclouvain.be>> wrote:

If I put
SetFactory("OpenCASCADE");

in the first line, then it gives me different error saying "unknown line loop with tag1"

Yes, there is no line loop 1 in your geometry... Only a surface 1 ("Rectangle" creates a surface...)

// mesh size description
SetFactory("OpenCASCADE");

cl_1   =  0.3;
cl_2   =  0.02;
cl3    =  0.02;
Mesh.CharacteristicLengthMax = 40;
extend = 15;

// define inversion region

Point(1) = {-0.05, 0.005, 0, cl_2};
Point(2) = {7.25, 0.005, 0, cl_2};
Point(3) = {7.25, -1.45, 0, cl_2};
Point(4) = {-0.05, -1.45, 0, cl_2};

// define bounding box

Point(5) = {-0.05-extend, 0.005, 0, cl_1};
Point(6) = {7.25+extend, 0.005, 0, cl_1};
Point(7) = {7.25+extend, -1.45-extend, 0, cl_1};
Point(8) = {-0.05-extend, -1.45-extend, 0, cl_1};

Line(1) = {1, 2};
Line(2) = {2, 6};
Line(3) = {6, 7};
Line(4) = {7, 8};
Line(5) = {8, 5};
Line(6) = {5, 1};
Line(7) = {1, 4};
Line(8) = {4, 3};
Line(9) = {3, 2};

// Definition of regions
Line Loop(101) = {2, 3, 4, 5, 6, 7, 8, 9};
Plane Surface(102) = {101}; // Outer box
Line Loop(105) = {1, -9, -8, -7};

// geological body

Rectangle(1) = {0.1, -0.2, 0, 0.5, 0.1, 0};
Rectangle(2) = {0.1, -1.0, 0, 0.3, 0.7, 0};
Rectangle(3) = {3.1, -0.6, 0, 1, 0.5, 0};
Rectangle(4) = {4.2, -1.2, 0, 1, 0.5, 0};
Rectangle(5) = {5.6, -0.9, 0, 1, 0.5, 0};
Plane Surface(110) = {105,1,2,3,4,5}; // Inner box without geological body

// Definition of boundaries
Physical Line(1) = {6, 2, 1}; // Free surface
Physical Line(2) = {3,4, 5}; // Mixed boundary conditions

// Definition of physical regions
Physical Surface(1)  = {102}; // No-inversion region
Physical Surface(2)  = {110}; // Inversion region
Physical Surface(3)  = {1}; // Geological body 1
Physical Surface(4)  = {2}; // Geological body 2
Physical Surface(5)  = {3}; // Geological body 3
Physical Surface(6)  = {4}; // Geological body 4
Physical Surface(7)  = {5}; // Geological body 5

________________________________
Best Regards,

Sathyanarayan Rao, PhD student
Earth and Life Institute/Environmental Sciences (ELI-e)
Université catholique de Louvain
c.037, Croix du Sud 2, Louvain-la-Neuve, Belgium
Phone: 010473827 ( intercom 73827)

________________________________

________________________________
From: Christophe Geuzaine <cgeuzaine at uliege.be<mailto:cgeuzaine at uliege.be>>
Sent: 22 February 2018 16:36:35
To: Sathyanarayan Rao
Cc: gmsh at onelab.info<mailto:gmsh at onelab.info>
Subject: Re: [Gmsh] Line loop and Open cascade

On 22 Feb 2018, at 12:56, Sathyanarayan Rao <sathyanarayan.rao at uclouvain.be<mailto:sathyanarayan.rao at uclouvain.be>> wrote:

Dear gmsh team,

Is it not possible to use both line loop type surface definition and open cascade rectangle. I always have problem with using both.

Sure you can: but you need to put SetFactory("OpenCASCADE") at the begining of your file: otherwise you create the first entities with the built-in CAD kernel ; and the rest (after SetFactory) with open cascade.

For example in the below code, surface 105 is unrecognized !

// mesh size description

cl_1   =  0.3;
cl_2   =  0.02;
cl3    =  0.02;
Mesh.CharacteristicLengthMax = 40;
extend = 15;

// define inversion region

Point(1) = {-0.05, 0.005, 0, cl_2};
Point(2) = {7.25, 0.005, 0, cl_2};
Point(3) = {7.25, -1.45, 0, cl_2};
Point(4) = {-0.05, -1.45, 0, cl_2};

// define bounding box

Point(5) = {-0.05-extend, 0.005, 0, cl_1};
Point(6) = {7.25+extend, 0.005, 0, cl_1};
Point(7) = {7.25+extend, -1.45-extend, 0, cl_1};
Point(8) = {-0.05-extend, -1.45-extend, 0, cl_1};

Line(1) = {1, 2};
Line(2) = {2, 6};
Line(3) = {6, 7};
Line(4) = {7, 8};
Line(5) = {8, 5};
Line(6) = {5, 1};
Line(7) = {1, 4};
Line(8) = {4, 3};
Line(9) = {3, 2};

// Definition of regions
Line Loop(101) = {2, 3, 4, 5, 6, 7, 8, 9};
Plane Surface(102) = {101}; // Outer box
Line Loop(105) = {1, -9, -8, -7};

// geological body

SetFactory("OpenCASCADE");
Rectangle(1) = {0.1, -0.2, 0, 0.5, 0.1, 0};
Rectangle(2) = {0.1, -1.0, 0, 0.3, 0.7, 0};
Rectangle(3) = {3.1, -0.6, 0, 1, 0.5, 0};
Rectangle(4) = {4.2, -1.2, 0, 1, 0.5, 0};
Rectangle(5) = {5.6, -0.9, 0, 1, 0.5, 0};
Plane Surface(110) = {105,1,2,3,4,5}; // Inner box without geological body

// Definition of boundaries
Physical Line(1) = {6, 2, 1}; // Free surface
Physical Line(2) = {3,4, 5}; // Mixed boundary conditions

// Definition of physical regions
Physical Surface(1)  = {102}; // No-inversion region
Physical Surface(2)  = {110}; // Inversion region
Physical Surface(3)  = {1}; // Geological body 1
Physical Surface(4)  = {2}; // Geological body 2
Physical Surface(5)  = {3}; // Geological body 3
Physical Surface(6)  = {4}; // Geological body 4
Physical Surface(7)  = {5}; // Geological body 5

________________________________
Best Regards,

Sathyanarayan Rao, PhD student
Earth and Life Institute/Environmental Sciences (ELI-e)
Université catholique de Louvain
c.037, Croix du Sud 2, Louvain-la-Neuve, Belgium
Phone: 010473827 ( intercom 73827)

________________________________

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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

—
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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