def write_stl_file(compound, filename, tolerance=None, angular_tolerance=None):
# Remove previous mesh data
BRepTools.Clean_s(compound)
mesh = BRepMesh_IncrementalMesh(compound, tolerance, True, angular_tolerance)
mesh.Perform()
writer = StlAPI_Writer()
result = writer.Write(compound, filename)
# Remove the mesh data again
BRepTools.Clean_s(compound)
return result
def compute(
self,
shape,
quality,
angular_tolerance,
tessellate=True,
compute_edges=True,
normals_len=0,
debug=False,
):
self.shape = shape
self.normals_len = normals_len
self.edges = []
count = self.number_solids(shape)
with Timer(debug, "", f"mesh incrementally {'(parallel)' if count > 1 else ''}", 3):
# Remove previous mesh data
BRepTools.Clean_s(shape)
BRepMesh_IncrementalMesh(shape, quality, False, angular_tolerance, count > 1)
if tessellate:
with Timer(debug, "", "get nodes, triangles and normals", 3):
self.tessellate()
if compute_edges:
with Timer(debug, "", "get edges", 3):
self.compute_edges()
def _fromTopoDS(
cls: Type["BoundBox"],
shape: TopoDS_Shape,
tol: Optional[float] = None,
optimal: bool = True,
):
"""
Constructs a bounding box from a TopoDS_Shape
"""
tol = TOL if tol is None else tol # tol = TOL (by default)
bbox = Bnd_Box()
if optimal:
BRepBndLib.AddOptimal_s(
shape, bbox
) # this is 'exact' but expensive - not yet wrapped by PythonOCC
else:
mesh = BRepMesh_IncrementalMesh(shape, tol, True)
mesh.Perform()
# this is adds +margin but is faster
BRepBndLib.Add_s(shape, bbox, True)
return cls(bbox)
def tessellate(shape, tolerance: float, angularTolerance: float = 0.1):
# Remove previous mesh data
BRepTools.Clean_s(shape)
triangulated = BRepTools.Triangulation_s(shape, tolerance)
if not triangulated:
# this will add mesh data to the shape and prevent calculating an exact bounding box after this call
BRepMesh_IncrementalMesh(shape, tolerance, True, angularTolerance)
vertices = []
triangles = []
normals = []
offset = 0
for face in get_faces(shape):
loc = TopLoc_Location()
poly = BRep_Tool.Triangulation_s(face, loc)
Trsf = loc.Transformation()
reverse = face.Orientation() == TopAbs_Orientation.TopAbs_REVERSED
internal = face.Orientation() == TopAbs_Orientation.TopAbs_INTERNAL
# add vertices
if poly is not None:
vertices += [(v.X(), v.Y(), v.Z())
for v in (v.Transformed(Trsf) for v in poly.Nodes())]
# add triangles
triangles += [(
t.Value(1) + offset - 1,
t.Value(3 if reverse else 2) + offset - 1,
t.Value(2 if reverse else 3) + offset - 1,
) for t in poly.Triangles()]
# add normals
if poly.HasUVNodes():
prop = BRepGProp_Face(face)
uvnodes = poly.UVNodes()
for uvnode in uvnodes:
p = gp_Pnt()
n = gp_Vec()
prop.Normal(uvnode.X(), uvnode.Y(), p, n)
if n.SquareMagnitude() > 0:
n.Normalize()
if internal:
n.Reverse()
normals.append((n.X(), n.Y(), n.Z()))
offset += poly.NbNodes()
if not triangulated:
# Remove the mesh data again
BRepTools.Clean_s(shape)
return (
np.asarray(vertices, dtype=np.float32),
np.asarray(triangles, dtype=np.uint32),
np.asarray(normals, dtype=np.float32),
)