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// -----------------------------------------------------------------------------
//
// Gmsh C++ tutorial 17
//
// Anisotropic background mesh
//
// -----------------------------------------------------------------------------
// As seen in `t7.cpp', mesh sizes can be specified very accurately by providing
// a background mesh, i.e., a post-processing view that contains the target mesh
// sizes.
// Here, the background mesh is represented as a metric tensor field defined on
// a square. One should use bamg as 2d mesh generator to enable anisotropic
// meshes in 2D.
#include <set>
#include <cmath>
#include <gmsh.h>
int main(int argc, char **argv)
{
gmsh::initialize();
gmsh::model::add("t17");
// Create a square
gmsh::model::occ::addRectangle(-2, -2, 0, 4, 4);
gmsh::model::occ::synchronize();
// Merge a post-processing view containing the target anisotropic mesh sizes
try {
gmsh::merge("../t17_bgmesh.pos");
} catch(...) {
gmsh::logger::write("Could not load background mesh: bye!");
gmsh::finalize();
return 0;
}
// Apply the view as the current background mesh
int bg_field = gmsh::model::mesh::field::add("PostView");
gmsh::model::mesh::field::setNumber(bg_field, "ViewIndex", 0);
gmsh::model::mesh::field::setAsBackgroundMesh(bg_field);
// Use bamg
gmsh::option::setNumber("Mesh.SmoothRatio", 3);
gmsh::option::setNumber("Mesh.AnisoMax", 1000);
gmsh::option::setNumber("Mesh.Algorithm", 7);
gmsh::model::mesh::generate(2);
gmsh::write("t17.msh");
// Launch the GUI to see the results:
std::set<std::string> args(argv, argv + argc);
if(!args.count("-nopopup")) gmsh::fltk::run();
gmsh::finalize();
return 0;
}
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