def face_mesh_triangle(comp=TopoDS_Shape(), isR=0.1, thA=0.1):
# Mesh the shape
BRepMesh_IncrementalMesh(comp, isR, True, thA, True)
bild1 = BRep_Builder()
comp1 = TopoDS_Compound()
bild1.MakeCompound(comp1)
bt = BRep_Tool()
ex = TopExp_Explorer(comp, TopAbs_FACE)
while ex.More():
face = topods_Face(ex.Current())
location = TopLoc_Location()
facing = bt.Triangulation(face, location)
tab = facing.Nodes()
tri = facing.Triangles()
print(facing.NbTriangles(), facing.NbNodes())
for i in range(1, facing.NbTriangles() + 1):
trian = tri.Value(i)
index1, index2, index3 = trian.Get()
for j in range(1, 4):
if j == 1:
m = index1
n = index2
elif j == 2:
n = index3
elif j == 3:
m = index2
me = BRepBuilderAPI_MakeEdge(tab.Value(m), tab.Value(n))
if me.IsDone():
bild1.Add(comp1, me.Edge())
ex.Next()
return comp1
def triangle_mesh_solid(solid, lin_tol=1e-2, ang_tol=0.5):
"""Computes a triangular mesh for a solid using BRepMesh.
The resolution or quality of the mesh approximation can be
adjusted with lin_tol and ang_tol (linear and angular tolerances).
The computed mesh is returned as a tuple of lists:
triangles - a list of each triangles' 3x vertices
represented as indexes into the vertices list
vertices - a list of the mesh's 3D vertices
"""
if isinstance(solid, Solid):
obj = [solid.wrapped]
elif isinstance(solid, list):
obj = [x.wrapped for x in solid]
else:
obj = [solid]
vertices = []
triangles = []
for o in obj:
mesh = BRepMesh_IncrementalMesh(o, lin_tol, False, ang_tol)
mesh.Perform()
ms = Shape.cast(mesh.Shape())
bt = BRep_Tool()
mesh_faces = ms.Faces()
for mesh_face in mesh_faces:
face = mesh_face.wrapped
location = TopLoc_Location()
facing = bt.Triangulation(face, location)
tri = facing.Triangles()
num_tri = facing.NbTriangles()
vtx = facing.Nodes()
txf = face.Location().Transformation()
rev = (True if face.Orientation()
== TopAbs_Orientation.TopAbs_REVERSED else False)
for i in range(1, num_tri + 1):
idx = list(tri.Value(i).Get())
ci = [0, 2, 1] if rev else [0, 1, 2]
for j in ci:
pt = [
vtx.Value(idx[j]).Transformed(txf).X(),
vtx.Value(idx[j]).Transformed(txf).Y(),
vtx.Value(idx[j]).Transformed(txf).Z(),
]
if pt not in vertices:
vertices.append(pt)
idx[j] = vertices.index(pt)
triangles.append(idx)
return triangles, vertices
def simple_mesh():
#
# Create the shape
#
theBox = BRepPrimAPI_MakeBox(200, 60, 60).Shape()
theSphere = BRepPrimAPI_MakeSphere(gp_Pnt(100, 20, 20), 80).Shape()
shape = BRepAlgoAPI_Fuse(theSphere, theBox).Shape()
#
# Mesh the shape
#
BRepMesh_IncrementalMesh(shape, 0.8)
builder = BRep_Builder()
comp = TopoDS_Compound()
builder.MakeCompound(comp)
bt = BRep_Tool()
ex = TopExp_Explorer(shape, TopAbs_FACE)
while ex.More():
face = topods_Face(ex.Current())
location = TopLoc_Location()
facing = (bt.Triangulation(face, location)).GetObject()
tab = facing.Nodes()
tri = facing.Triangles()
for i in range(1, facing.NbTriangles() + 1):
trian = tri.Value(i)
index1, index2, index3 = trian.Get()
for j in range(1, 4):
if j == 1:
m = index1
n = index2
elif j == 2:
n = index3
elif j == 3:
m = index2
me = BRepBuilderAPI_MakeEdge(tab.Value(m), tab.Value(n))
if me.IsDone():
builder.Add(comp, me.Edge())
ex.Next()
display.EraseAll()
display.DisplayShape(shape)
display.DisplayShape(comp, update=True)
# BRep
# ==============================================================================
brep = BRep()
brep.shape = face
# mesh = brep.to_tesselation()
BRepMesh_IncrementalMesh(brep.shape, 0.1, False, 0.1, False)
bt = BRep_Tool()
ex = TopExp_Explorer(brep.shape, TopAbs_FACE)
while ex.More():
face = topods_Face(ex.Current())
location = TopLoc_Location()
facing = (bt.Triangulation(face, location))
tab = facing.Nodes()
tri = facing.Triangles()
for i in range(1, facing.NbTriangles() + 1):
trian = tri.Value(i)
index1, index2, index3 = trian.Get()
# for j in range(1, 4):
# if j == 1:
# m = index1
# n = index2
# elif j == 2:
# n = index3
# elif j == 3:
# m = index2
# me = BRepBuilderAPI_MakeEdge(tab.Value(m), tab.Value(n))
# if me.IsDone():
def __init__(self, shape):
from OCC.Core.BRep import BRep_Tool
from OCC.Core.BRepMesh import BRepMesh_IncrementalMesh
from OCC.Core.TopAbs import TopAbs_FACE, TopAbs_VERTEX
from OCC.Core.TopExp import TopExp_Explorer
from OCC.Core.TopLoc import TopLoc_Location
from OCC.Core.TopoDS import topods_Face, topods_Vertex, TopoDS_Iterator
vertices = [] # a (nested) list of vec3
triangles = [] # a (flat) list of integers
normals = []
uv = []
# Mesh the shape
linDeflection = 0.8
BRepMesh_IncrementalMesh(shape, linDeflection)
bt = BRep_Tool()
# Explore the faces of the shape
# each face is triangulated, we need to collect all the parts
expFac = TopExp_Explorer(shape, TopAbs_FACE)
while expFac.More():
face = topods_Face(expFac.Current())
location = TopLoc_Location()
facing = (bt.Triangulation(face, location))
try:
tri = facing.Triangles()
nTri = facing.NbTriangles()
ver = facing.Nodes()
except:
tri = None
nTri = None
ver = None
# store origin of the face's local coordinates
transf = face.Location().Transformation()
# iterate over triangles and store indices of vertices defining each triangle
# OCC uses one-based indexing
for i in range(1, nTri + 1):
# each triangle is defined by three points
# each point is defined by its index in the list of vertices
index1, index2, index3 = tri.Value(i).Get()
indices = [index1, index2, index3]
# python uses zero-based indexing
# for each vertex of a triangle, check whether it is already known
# then store it (or not) and update the index
for idx in [0, 1, 2]:
# read global coordinates of each point
vec3 = [
ver.Value(indices[idx]).Transformed(transf).X(),
ver.Value(indices[idx]).Transformed(transf).Y(),
ver.Value(indices[idx]).Transformed(transf).Z()
]
if vec3 not in vertices:
vertices.append(vec3)
indices[idx] = vertices.index(vec3)
triangles.extend(indices)
expFac.Next()
self.shape = shape
self.vertices = vertices
self.triangles = triangles
self.normals = normals
self.uv = uv