julia version

demos/api/terrain_bspline.jl

+import gmsh
+
+gmsh.initialize()
+
+gmsh.model.add("terrain")
+
+# create the terrain surface from N x N input data points (here simulated using
+# a simple function):
+N = 100
+ps = []
+
+# create a bspline surface
+for i in 0:N
+    for j in 0:N
+        push!(ps, gmsh.model.occ.addPoint(float(i) / N, float(j) / N,
+                                          0.05 * sin(10 * float(i + j) / N)))
+    end
+end
+s = gmsh.model.occ.addBSplineSurface(ps, N+1)
+
+# create a box
+v = gmsh.model.occ.addBox(0, 0, -0.5, 1, 1, 1)
+
+# fragment the box with the bspline surface
+gmsh.model.occ.fragment([(2, s)], [(3, v)])
+gmsh.model.occ.synchronize()
+
+# define a parameter to select the mesh type interactively
+gmsh.onelab.set("""[
+  {
+    "type":"number",
+    "name":"Parameters/Full-hex mesh?",
+    "values":[0],
+    "choices":[0, 1]
+  }
+]""")
+
+
+function setMeshConstraint()
+    if gmsh.onelab.getNumber("Parameters/Full-hex mesh?")[1] == 1
+        NN = 30
+        for c in gmsh.model.getEntities(1)
+            gmsh.model.mesh.setTransfiniteCurve(c[2], NN)
+            for s in gmsh.model.getEntities(2)
+                gmsh.model.mesh.setTransfiniteSurface(s[2])
+                gmsh.model.mesh.setRecombine(s[1], s[2])
+                gmsh.model.mesh.setSmoothing(s[1], s[2], 100)
+            end
+        end
+        gmsh.model.mesh.setTransfiniteVolume(1)
+        gmsh.model.mesh.setTransfiniteVolume(2)
+    else
+        gmsh.model.mesh.removeConstraints()
+        gmsh.option.setNumber("Mesh.MeshSizeMin", 0.05)
+        gmsh.option.setNumber("Mesh.MeshSizeMax", 0.05)
+    end
+end
+
+setMeshConstraint()
+
+function checkForEvent()
+    action = gmsh.onelab.getString("ONELAB/Action")
+    if length(action) > 0 && action[1] == "check"
+        gmsh.onelab.setString("ONELAB/Action", [""])
+        setMeshConstraint()
+    end
+    return true
+end
+
+if !("-nopopup" in ARGS)
+    gmsh.fltk.initialize()
+    while gmsh.fltk.isAvailable() == 1 && checkForEvent()
+        gmsh.fltk.wait()
+    end
+end
+
+gmsh.finalize()