def simple_mesh(occshape, mesh_incremental_float=0.8):
#TODO: figure out why is it that some surfaces do not work
occshape = TopoDS_Shape(occshape)
bt = BRep_Tool()
BRepMesh_IncrementalMesh(occshape, mesh_incremental_float)
occshape_face_list = fetch.geom_explorer(occshape, "face")
occface_list = []
for occshape_face in occshape_face_list:
location = TopLoc_Location()
#occshape_face = modify.fix_face(occshape_face)
facing = bt.Triangulation(occshape_face, location).GetObject()
if facing:
tab = facing.Nodes()
tri = facing.Triangles()
for i in range(1, facing.NbTriangles() + 1):
trian = tri.Value(i)
index1, index2, index3 = trian.Get()
#print index1, index2, index3
pypt1 = fetch.occpt2pypt(tab.Value(index1))
pypt2 = fetch.occpt2pypt(tab.Value(index2))
pypt3 = fetch.occpt2pypt(tab.Value(index3))
#print pypt1, pypt2, pypt3
occface = make_polygon([pypt1, pypt2, pypt3])
occface_list.append(occface)
return occface_list
def simple_mesh():
#
# Create the shape
#
shape = BRepPrimAPI_MakeBox(200, 200, 200).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)
def __init__(self, shape):
from OCC.BRep import BRep_Tool
from OCC.BRepMesh import BRepMesh_IncrementalMesh
from OCC.TopAbs import TopAbs_FACE, TopAbs_VERTEX
from OCC.TopExp import TopExp_Explorer
from OCC.TopLoc import TopLoc_Location
from OCC.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)).GetObject()
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