Creating Meshes

First of all see Example of 3d mesh generation, which is an example of good python script style for Mesh module.

Other examples of python scripts will be also updated soon to use smesh package instead of direct usage of idl interface.

Construction of a Mesh

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

Construction of a Submesh

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()

Editing of a mesh

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)

Export of a Mesh

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)