// ----------------------------------------------------------------------------- // // Gmsh C++ tutorial 4 // // Holes in surfaces, annotations, entity colors // // ----------------------------------------------------------------------------- #include <set> #include <cmath> #include <gmsh.h> double hypoth(double a, double b) { return sqrt(a * a + b * b); } int main(int argc, char **argv) { gmsh::initialize(argc, argv); gmsh::model::add("t4"); double cm = 1e-02; double e1 = 4.5 * cm, e2 = 6 * cm / 2, e3 = 5 * cm / 2; double h1 = 5 * cm, h2 = 10 * cm, h3 = 5 * cm, h4 = 2 * cm, h5 = 4.5 * cm; double R1 = 1 * cm, R2 = 1.5 * cm, r = 1 * cm; double Lc1 = 0.01; double Lc2 = 0.003; double ccos = (-h5 * R1 + e2 * hypot(h5, hypot(e2, R1))) / (h5 * h5 + e2 * e2); double ssin = sqrt(1 - ccos * ccos); // We start by defining some points and some lines. To make the code shorter // we can redefine a namespace: namespace factory = gmsh::model::geo; factory::addPoint(-e1 - e2, 0, 0, Lc1, 1); factory::addPoint(-e1 - e2, h1, 0, Lc1, 2); factory::addPoint(-e3 - r, h1, 0, Lc2, 3); factory::addPoint(-e3 - r, h1 + r, 0, Lc2, 4); factory::addPoint(-e3, h1 + r, 0, Lc2, 5); factory::addPoint(-e3, h1 + h2, 0, Lc1, 6); factory::addPoint(e3, h1 + h2, 0, Lc1, 7); factory::addPoint(e3, h1 + r, 0, Lc2, 8); factory::addPoint(e3 + r, h1 + r, 0, Lc2, 9); factory::addPoint(e3 + r, h1, 0, Lc2, 10); factory::addPoint(e1 + e2, h1, 0, Lc1, 11); factory::addPoint(e1 + e2, 0, 0, Lc1, 12); factory::addPoint(e2, 0, 0, Lc1, 13); factory::addPoint(R1 / ssin, h5 + R1 * ccos, 0, Lc2, 14); factory::addPoint(0, h5, 0, Lc2, 15); factory::addPoint(-R1 / ssin, h5 + R1 * ccos, 0, Lc2, 16); factory::addPoint(-e2, 0.0, 0, Lc1, 17); factory::addPoint(-R2, h1 + h3, 0, Lc2, 18); factory::addPoint(-R2, h1 + h3 + h4, 0, Lc2, 19); factory::addPoint(0, h1 + h3 + h4, 0, Lc2, 20); factory::addPoint(R2, h1 + h3 + h4, 0, Lc2, 21); factory::addPoint(R2, h1 + h3, 0, Lc2, 22); factory::addPoint(0, h1 + h3, 0, Lc2, 23); factory::addPoint(0, h1 + h3 + h4 + R2, 0, Lc2, 24); factory::addPoint(0, h1 + h3 - R2, 0, Lc2, 25); factory::addLine(1, 17, 1); factory::addLine(17, 16, 2); // Gmsh provides other curve primitives than straight lines: splines, // B-splines, circle arcs, ellipse arcs, etc. Here we define a new circle arc, // starting at point 14 and ending at point 16, with the circle's center being // the point 15: factory::addCircleArc(14, 15, 16, 3); // Note that, in Gmsh, circle arcs should always be smaller than Pi. The // OpenCASCADE geometry kernel does not have this limitation. // We can then define additional lines and circles, as well as a new surface: factory::addLine(14, 13, 4); factory::addLine(13, 12, 5); factory::addLine(12, 11, 6); factory::addLine(11, 10, 7); factory::addCircleArc(8, 9, 10, 8); factory::addLine(8, 7, 9); factory::addLine(7, 6, 10); factory::addLine(6, 5, 11); factory::addCircleArc(3, 4, 5, 12); factory::addLine(3, 2, 13); factory::addLine(2, 1, 14); factory::addLine(18, 19, 15); factory::addCircleArc(21, 20, 24, 16); factory::addCircleArc(24, 20, 19, 17); factory::addCircleArc(18, 23, 25, 18); factory::addCircleArc(25, 23, 22, 19); factory::addLine(21, 22, 20); factory::addCurveLoop({17, -15, 18, 19, -20, 16}, 21); factory::addPlaneSurface({21}, 22); // But we still need to define the exterior surface. Since this surface has a // hole, its definition now requires two curves loops: factory::addCurveLoop({11, -12, 13, 14, 1, 2, -3, 4, 5, 6, 7, -8, 9, 10}, 23); factory::addPlaneSurface({23, 21}, 24); // As a general rule, if a surface has N holes, it is defined by N+1 curve // loops: the first loop defines the exterior boundary; the other loops define // the boundaries of the holes. factory::synchronize(); // Finally, we can add some comments by creating a post-processing view // containing some strings: int v = gmsh::view::add("comments"); // Add a text string in window coordinates, 10 pixels from the left and 10 // pixels from the bottom: gmsh::view::addListDataString(v, {10, -10}, {"Created with Gmsh"}); // Add a text string in model coordinates centered at (X,Y,Z) = (0, 0.11, 0), // with some style attributes: gmsh::view::addListDataString(v, {0, 0.11, 0}, {"Hole"}, {"Align", "Center", "Font", "Helvetica"}); // If a string starts with `file://', the rest is interpreted as an image // file. For 3D annotations, the size in model coordinates can be specified // after a `@' symbol in the form `widthxheight' (if one of `width' or // `height' is zero, natural scaling is used; if both are zero, original image // dimensions in pixels are used): gmsh::view::addListDataString( v, {0, 0.09, 0}, {"file://../t4_image.png@0.01x0"}, {"Align", "Center"}); // The 3D orientation of the image can be specified by proving the direction // of the bottom and left edge of the image in model space: gmsh::view::addListDataString(v, {-0.01, 0.09, 0}, {"file://../t4_image.png@0.01x0,0,0,1,0,1,0"}); // The image can also be drawn in "billboard" mode, i.e. always parallel to // the camera, by using the `#' symbol: gmsh::view::addListDataString( v, {0, 0.12, 0}, {"file://../t4_image.png@0.01x0#"}, {"Align", "Center"}); // The size of 2D annotations is given directly in pixels: gmsh::view::addListDataString(v, {150, -7}, {"file://../t4_image.png@20x0"}); // These annotations are handled by a list-based post-processing view. For // large post-processing datasets, that contain actual field values defined on // a mesh, you should use model-based post-processing views instead, which // allow to efficiently store continuous or discontinuous scalar, vector and // tensor fields, or arbitrary polynomial order. // Views and geometrical entities can be made to respond to double-click // events, here to print some messages to the console: gmsh::option::setString("View[0].DoubleClickedCommand", "Printf('View[0] has been double-clicked!');"); gmsh::option::setString("Geometry.DoubleClickedLineCommand", "Printf('Curve %g has been double-clicked!', " "Geometry.DoubleClickedEntityTag);"); // We can also change the color of some entities: gmsh::model::setColor({{2, 22}}, 127, 127, 127); // Gray50 gmsh::model::setColor({{2, 24}}, 160, 32, 240); // Purple for(int i = 1; i <= 14; i++) gmsh::model::setColor({{1, i}}, 255, 0, 0); // Red for(int i = 15; i <= 20; i++) gmsh::model::setColor({{1, i}}, 255, 255, 0); // Yellow gmsh::model::mesh::generate(2); gmsh::write("t4.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; }