def test_mesh_sphere_quadrangle(self):
aShape = BRepPrimAPI_MakeSphere(10.).Shape()
# Create the Mesh
aMeshGen = SMESH_Gen()
aMesh = aMeshGen.CreateMesh(0, True)
# 1D
an1DHypothesis = StdMeshers_Arithmetic1D(
0, 0, aMeshGen) #discretization of the wire
an1DHypothesis.SetLength(
0.1, False) #the smallest distance between 2 points
an1DHypothesis.SetLength(0.5,
True) # the longest distance between 2 points
an1DAlgo = StdMeshers_Regular_1D(1, 0, aMeshGen) # interpolation
# 2D
a2dHypothseis = StdMeshers_TrianglePreference(
2, 0, aMeshGen) #define the boundary
a2dAlgo = StdMeshers_Quadrangle_2D(3, 0, aMeshGen) # the 2D mesh
#Calculate mesh
aMesh.ShapeToMesh(aShape)
#Assign hyptothesis to mesh
aMesh.AddHypothesis(aShape, 0)
aMesh.AddHypothesis(aShape, 1)
aMesh.AddHypothesis(aShape, 2)
aMesh.AddHypothesis(aShape, 3)
#Compute the data
aMeshGen.Compute(aMesh, aMesh.GetShapeToMesh())
def smesh_MEFISTO2D(event=None):
# Create the Mesh
aMeshGen = SMESH_Gen()
aMesh = aMeshGen.CreateMesh(0, True)
# 1D
an1DHypothesis = StdMeshers_Arithmetic1D(
0, 0, aMeshGen) # discretization of the wire
an1DHypothesis.SetLength(0.1,
False) # the smallest distance between 2 points
an1DHypothesis.SetLength(0.5,
True) # the longest distance between 2 points
an1DAlgo = StdMeshers_Regular_1D(1, 0, aMeshGen) # interpolation
# 2D
a2dHypothseis = StdMeshers_TrianglePreference(
2, 0, aMeshGen) # define the boundary
a2dAlgo = StdMeshers_MEFISTO_2D(3, 0, aMeshGen)
# alculate mesh
aMesh.ShapeToMesh(aShape)
# Assign hyptothesis to mesh
aMesh.AddHypothesis(aShape, 0)
aMesh.AddHypothesis(aShape, 1)
aMesh.AddHypothesis(aShape, 2)
aMesh.AddHypothesis(aShape, 3)
# Compute the data
aMeshGen.Compute(aMesh, aMesh.GetShapeToMesh())
# Display the data
display_mesh(aMesh)
def generate_stl(self, min_length=None, max_length=None, outfile_stl=None):
"""
Generate and export the .STL surface mesh for the blade as a whole,
including the upper face, lower face and tip. The method utilizes
modules from OCC SMESH which is standalone mesh framework based on
SALOME mesher project. Please refer to https://github.com/tpaviot
and http://docs.salome-platform.org/7/gui/SMESH/index.html for
further details.
This method requires PythonOCC and SMESH to be installed.
:param double min_length: smallest distance between two nodes. Default
value is None
:param double max_length: largest distance between two nodes. Default
value is None
:param string outfile_stl: if string is passed then the method exports
the generated 2D surface mesh into .stl file holding the name
<outfile_stl>.stl. Default value is None
We note that since the current implementation performs triangulation
based on a topological compound that combines the blade 3 generated
shapes without "fusion", it may happen that the generated triangulation
of the upper and lower blade faces do not share the same exact nodes
on the joint edge/wire resulting from the faces intersection. The
current implementation can be enough for visualization purpose. However
if the generated mesh is intended for computational analysis then a
manual mesh healing is recommended by the user (e.g. see
"Repair > Sewing" in SALOME GUI) for a proper mesh closure.
"""
from OCC.Core.SMESH import SMESH_Gen
from OCC.Core.StdMeshers import (StdMeshers_Arithmetic1D,
StdMeshers_TrianglePreference,
StdMeshers_Regular_1D,
StdMeshers_MEFISTO_2D)
from OCC.Core.BRep import BRep_Builder
from OCC.Core.TopoDS import TopoDS_Shape, TopoDS_Compound
if min_length <= 0 or max_length <= 0:
raise ValueError('min_length and max_length must be positive.')
if min_length >= max_length:
raise ValueError('min_length can not be greater than max_length')
# First we check that blade shapes are generated, otherwise we generate
# them. After that we combine the generated_upper_face,
# generated_lower_face, and generated_tip into a topological compound
# that we use to compute the surface mesh
if (self.generated_upper_face is None) or not isinstance(
self.generated_upper_face, TopoDS_Shape):
# Upper face is generated with a maximal U degree = 1
self._generate_upper_face(maxDeg=1)
if (self.generated_lower_face is None) or not isinstance(
self.generated_lower_face, TopoDS_Shape):
# Upper face is generated with a maximal U degree = 1
self._generate_lower_face(maxDeg=1)
if (self.generated_tip is None) or not isinstance(
self.generated_tip, TopoDS_Shape):
# Upper face is generated with a maximal U degree = 1
self._generate_tip(maxDeg=1)
# Now we regroup all the shapes into a TopoDS_Compound
aCompound = TopoDS_Compound()
aBuilder = BRep_Builder()
aBuilder.MakeCompound(aCompound)
# Add shapes
aBuilder.Add(aCompound, self.generated_upper_face)
aBuilder.Add(aCompound, self.generated_lower_face)
aBuilder.Add(aCompound, self.generated_tip)
# In the following we build the surface mesh according to the given
# hypotheses
aMeshGen = SMESH_Gen()
aMesh = aMeshGen.CreateMesh(0, True)
# Adding 1D hypothesis and algorithms
# Wire discretization. Nodes are distributed based on Arithmetic1D
# hypothesis which allows to split edges into segments with a length
# that changes in arithmetic progression (Lk = Lk-1 + d) beginning
# from a given min length and up to a given max length. More about
# 1D hypotheses can be viewed through:
# http://docs.salome-platform.org/7/gui/SMESH/a1d_meshing_hypo_page.html
an1DHypothesis = StdMeshers_Arithmetic1D(0, 0, aMeshGen)
# Smallest distance between 2 points
an1DHypothesis.SetLength(min_length, False)
# Longest distance between 2 points
an1DHypothesis.SetLength(max_length, True)
# Regular Interpolation
an1DAlgo = StdMeshers_Regular_1D(1, 0, aMeshGen)
# Adding 2D hypothesis and algorithms
# 2D surface mesh -- Triangulations
a2dHypothseis = StdMeshers_TrianglePreference(2, 0, aMeshGen)
a2dAlgo = StdMeshers_MEFISTO_2D(3, 0, aMeshGen)
#Calculate mesh for the topological compound containing the 3 shapes
aMesh.ShapeToMesh(aCompound)
#Assign hyptothesis to mesh
aMesh.AddHypothesis(aCompound, 0)
aMesh.AddHypothesis(aCompound, 1)
aMesh.AddHypothesis(aCompound, 2)
aMesh.AddHypothesis(aCompound, 3)
if outfile_stl is not None:
if not isinstance(outfile_stl, str):
raise ValueError('outfile_stl must be a valid string.')
#Compute the data
aMeshGen.Compute(aMesh, aMesh.GetShapeToMesh())
# Export STL
aMesh.ExportSTL(outfile_stl + '.stl', False)
from OCC.Core.SMDSAbs import SMDSAbs_Face
from OCC.Display.SimpleGui import init_display
display, start_display, add_menu, add_function_to_menu = init_display()
# First create a 'complex' shape (actually a boolean op between a box and a cylinder)
print('Creating geometry ...', end='')
box = BRepPrimAPI_MakeBox(200, 30, 30).Shape()
sphere = BRepPrimAPI_MakeSphere(gp_Pnt(150, 20, 20), 80).Shape()
aShape = BRepAlgoAPI_Cut(box, sphere).Shape()
print('Done.')
# Create the Mesh
print('Creating mesh ...', end='')
aMeshGen = SMESH_Gen()
aMesh = aMeshGen.CreateMesh(0, True)
print('Done.')
print('Adding hypothesis and algorithms ...', end='')
# 1D
an1DHypothesis = StdMeshers_Arithmetic1D(
0, 0, aMeshGen) # discretization of the wire
an1DHypothesis.SetLength(5., False) # the smallest distance between 2 points
an1DHypothesis.SetLength(10., True) # the longest distance between 2 points
an1DAlgo = StdMeshers_Regular_1D(1, 0, aMeshGen) # interpolation
# 2D
a2dHypothseis = StdMeshers_QuadranglePreference(
2, 0, aMeshGen) # define the boundary
a2dAlgo = StdMeshers_Quadrangle_2D(3, 0, aMeshGen) # the 2D mesh
