First of all see Example of 3d mesh generation, which is an example of good python script style for Mesh module.
import geompy import smesh # create a box box = geompy.MakeBox(0., 0., 0., 100., 200., 300.) idbox = geompy.addToStudy(box, "box") # create a mesh tetra = smesh.Mesh(box, "MeshBox") algo1D = tetra.Segment() algo1D.NumberOfSegments(7) algo2D = tetra.Triangle() algo2D.MaxElementArea(800.) algo3D = tetra.Tetrahedron(smesh.NETGEN) algo3D.MaxElementVolume(900.) # compute the mesh ret = tetra.Compute() if ret == 0: print "problem when computing the mesh" else: print "mesh computed" pass
from geompy import * import smesh # create a box box = MakeBoxDXDYDZ(10., 10., 10.) addToStudy(box, "Box") # select one edge of the box for definition of a local hypothesis p5 = MakeVertex(5., 0., 0.) EdgeX = GetEdgeNearPoint(box, p5) addToStudyInFather(box, EdgeX, "Edge [0,0,0 - 10,0,0]") # create a hexahedral mesh on the box quadra = smesh.Mesh(box, "Box : quadrangle 2D mesh") # create a regular 1D algorithm for the faces algo1D = quadra.Segment() # define "NumberOfSegments" hypothesis to cut # all the edges in a fixed number of segments algo1D.NumberOfSegments(4) # create a quadrangle 2D algorithm for the faces quadra.Quadrangle() # construct a submesh on the edge with a local hypothesis algo_local = quadra.Segment(EdgeX) # define "Arithmetic1D" hypothesis to cut the edge in several segments with increasing arithmetic length algo_local.Arithmetic1D(1, 4) # define "Propagation" hypothesis that propagates all other hypotheses # on all edges of the opposite side in case of quadrangular faces algo_local.Propagation() # compute the mesh quadra.Compute()
import geompy import smesh def PrintMeshInfo(theMesh): aMesh = theMesh.GetMesh() print "Information about mesh:" print "Number of nodes : ", aMesh.NbNodes() print "Number of edges : ", aMesh.NbEdges() print "Number of faces : ", aMesh.NbFaces() print "Number of volumes : ", aMesh.NbVolumes() pass # create a box box = geompy.MakeBox(0., 0., 0., 20., 20., 20.) geompy.addToStudy(box, "box") # select one edge of the box for definition of a local hypothesis subShapeList = geompy.SubShapeAll(box, geompy.ShapeType["EDGE"]) edge = subShapeList[0] name = geompy.SubShapeName(edge, box) geompy.addToStudyInFather(box, edge, name) # create a mesh tria = smesh.Mesh(box, "Mesh 2D") algo1D = tria.Segment() hyp1 = algo1D.NumberOfSegments(3) algo2D = tria.Triangle() hyp2 = algo2D.MaxElementArea(10.) # create a sub-mesh algo_local = tria.Segment(edge) hyp3 = algo_local.Arithmetic1D(1, 6) hyp4 = algo_local.Propagation() # compute the mesh tria.Compute() PrintMeshInfo(tria) # remove a local hypothesis mesh = tria.GetMesh() mesh.RemoveHypothesis(edge, hyp4) # compute the mesh tria.Compute() PrintMeshInfo(tria) # change the value of the 2D hypothesis hyp2.SetMaxElementArea(2.) # compute the mesh tria.Compute() PrintMeshInfo(tria)
import geompy import smesh # create a box box = geompy.MakeBox(0., 0., 0., 100., 200., 300.) idbox = geompy.addToStudy(box, "box") # create a mesh tetra = smesh.Mesh(box, "MeshBox") algo1D = tetra.Segment() algo1D.NumberOfSegments(7) algo2D = tetra.Triangle() algo2D.MaxElementArea(800.) algo3D = tetra.Tetrahedron(smesh.NETGEN) algo3D.MaxElementVolume(900.) # compute the mesh tetra.Compute() # export the mesh in a MED file tetra.ExportMED("/tmp/meshMED.med", 0)
Here you can see an example of python script, creating a hexahedral mesh on a cylinder. And a picture below the source code of the script, demonstrating the resulting mesh.
# -*- coding: iso-8859-1 -*- # Copyright (C) 2007-2008 CEA/DEN, EDF R&D, OPEN CASCADE # # Copyright (C) 2003-2007 OPEN CASCADE, EADS/CCR, LIP6, CEA/DEN, # CEDRAT, EDF R&D, LEG, PRINCIPIA R&D, BUREAU VERITAS # # This library is free software; you can redistribute it and/or # modify it under the terms of the GNU Lesser General Public # License as published by the Free Software Foundation; either # version 2.1 of the License. # # This library is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU # Lesser General Public License for more details. # # You should have received a copy of the GNU Lesser General Public # License along with this library; if not, write to the Free Software # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA # # See http://www.salome-platform.org/ or email : webmaster.salome@opencascade.com # # ================================== # import math import geompy import smesh geo = geompy # Parameters # ---------- radius = 50 height = 200 # Build a cylinder # ---------------- base = geo.MakeVertex(0, 0, 0) direction = geo.MakeVectorDXDYDZ(0, 0, 1) cylinder = geo.MakeCylinder(base, direction, radius, height) geo.addToStudy(cylinder, "cylinder") # Build blocks # ------------ size = radius/2.0 box_rot = geo.MakeBox(-size, -size, 0, +size, +size, height) box_axis = geo.MakeLine(base, direction) box = geo.MakeRotation(box_rot, box_axis, math.pi/4) hole = geo.MakeCut(cylinder, box) plane_trim = 2000 plane_a = geo.MakePlane(base, geo.MakeVectorDXDYDZ(1, 0, 0), plane_trim) plane_b = geo.MakePlane(base, geo.MakeVectorDXDYDZ(0, 1, 0), plane_trim) blocks_part = geo.MakePartition([hole], [plane_a, plane_b], [], [], geo.ShapeType["SOLID"]) blocks_list = [box] + geo.SubShapeAll(blocks_part, geo.ShapeType["SOLID"]) blocks_all = geo.MakeCompound(blocks_list) blocks = geo.MakeGlueFaces(blocks_all, 0.0001) geo.addToStudy(blocks, "cylinder:blocks") # Build geometric groups # ---------------------- def group(name, shape, type, base=None, direction=None): t = geo.ShapeType[type] g = geo.CreateGroup(shape, t) geo.addToStudy(g, name) g.SetName(name) if base!=None: l = geo.GetShapesOnPlaneWithLocationIDs(shape, t, direction, base, geo.GEOM.ST_ON) geo.UnionIDs(g, l) return g group_a = group("baseA", blocks, "FACE", base, direction) base_b = geo.MakeVertex(0, 0, height) group_b = group("baseB", blocks, "FACE", base_b, direction) group_1 = group("limit", blocks, "SOLID") group_1_all = geo.SubShapeAllIDs(blocks, geo.ShapeType["SOLID"]) geo.UnionIDs(group_1, group_1_all) group_1_box = geo.GetBlockNearPoint(blocks, base) geo.DifferenceList(group_1, [group_1_box]) # Mesh the blocks with hexahedral # ------------------------------- def discretize(x, y, z, n, s=blocks): p = geo.MakeVertex(x, y, z) e = geo.GetEdgeNearPoint(s, p) a = hexa.Segment(e) a.NumberOfSegments(n) a.Propagation() hexa = smesh.Mesh(blocks) hexa_1d = hexa.Segment() hexa_1d.NumberOfSegments(1) discretize(+radius , +radius, 0, 5) discretize(-radius , +radius, 0, 8) discretize((radius+size)/2, 0, 0, 10) discretize( +radius, 0, height/2, 20) hexa.Quadrangle() hexa.Hexahedron() hexa.Compute() hexa.Group(group_a) hexa.Group(group_b) hexa.Group(group_1)
import geompy import smesh ## create a bottom box Box_inf = geompy.MakeBox(0., 0., 0., 200., 200., 50.) # get a top face Psup1=geompy.MakeVertex(100., 100., 50.) Fsup1=geompy.GetFaceNearPoint(Box_inf, Psup1) # get a bottom face Pinf1=geompy.MakeVertex(100., 100., 0.) Finf1=geompy.GetFaceNearPoint(Box_inf, Pinf1) ## create a top box Box_sup = geompy.MakeBox(100., 100., 50., 200., 200., 100.) # get a top face Psup2=geompy.MakeVertex(150., 150., 100.) Fsup2=geompy.GetFaceNearPoint(Box_sup, Psup2) # get a bottom face Pinf2=geompy.MakeVertex(150., 150., 50.) Finf2=geompy.GetFaceNearPoint(Box_sup, Pinf2) ## Publish in the study geompy.addToStudy(Box_inf, "Box_inf") geompy.addToStudyInFather(Box_inf, Fsup1, "Fsup") geompy.addToStudyInFather(Box_inf, Finf1, "Finf") geompy.addToStudy(Box_sup, "Box_sup") geompy.addToStudyInFather(Box_sup, Fsup2, "Fsup") geompy.addToStudyInFather(Box_sup, Finf2, "Finf") ## create a bottom mesh Mesh_inf = smesh.Mesh(Box_inf, "Mesh_inf") algo1D_1=Mesh_inf.Segment() algo1D_1.NumberOfSegments(10) algo2D_1=Mesh_inf.Quadrangle() algo3D_1=Mesh_inf.Hexahedron() Mesh_inf.Compute() # create a group on the top face Gsup1=Mesh_inf.Group(Fsup1, "Sup") # create a group on the bottom face Ginf1=Mesh_inf.Group(Finf1, "Inf") ## create a top mesh Mesh_sup = smesh.Mesh(Box_sup, "Mesh_sup") algo1D_2=Mesh_sup.Segment() algo1D_2.NumberOfSegments(5) algo2D_2=Mesh_sup.Quadrangle() algo3D_2=Mesh_sup.Hexahedron() Mesh_sup.Compute() # create a group on the top face Gsup2=Mesh_sup.Group(Fsup2, "Sup") # create a group on the bottom face Ginf2=Mesh_sup.Group(Finf2, "Inf") ## create compounds # create a compound of two meshes with renaming groups with the same names and # merging of elements with the given tolerance Compound1 = smesh.smesh.Concatenate([Mesh_inf.GetMesh(), Mesh_sup.GetMesh()], 0, 1, 1e-05) smesh.SetName(Compound1, 'Compound_with_RenamedGrps_and_MergeElems') # create a compound of two meshes with uniting groups with the same names and # creating groups of all elements Compound2 = smesh.smesh.Concatenate([Mesh_inf.GetMesh(), Mesh_sup.GetMesh()], 1, 0, 1e-05, True) smesh.SetName(Compound2, 'Compound_with_UniteGrps_and_GrpsOfAllElems') #end