def recognize_face(a_face):
""" Takes a TopoDS shape and tries to identify its nature
whether it is a plane a cylinder a torus etc.
if a plane, returns the normal
if a cylinder, returns the radius
"""
surf = BRepAdaptor_Surface(a_face, True)
surf_type = surf.GetType()
if surf_type == GeomAbs_Plane:
print("--> plane")
# look for the properties of the plane
# first get the related gp_Pln
gp_pln = surf.Plane()
location = gp_pln.Location() # a point of the plane
normal = gp_pln.Axis().Direction() # the plane normal
# then export location and normal to the console output
print("--> Location (global coordinates)", location.X(), location.Y(), location.Z())
print("--> Normal (global coordinates)", normal.X(), normal.Y(), normal.Z())
elif surf_type == GeomAbs_Cylinder:
print("--> cylinder")
# look for the properties of the cylinder
# first get the related gp_Cyl
gp_cyl = surf.Cylinder()
location = gp_cyl.Location() # a point of the axis
axis = gp_cyl.Axis().Direction() # the cylinder axis
# then export location and normal to the console output
print("--> Location (global coordinates)", location.X(), location.Y(), location.Z())
print("--> Axis (global coordinates)", axis.X(), axis.Y(), axis.Z())
else:
# TODO there are plenty other type that can be checked
# see documentation for the BRepAdaptor class
# https://www.opencascade.com/doc/occt-6.9.1/refman/html/class_b_rep_adaptor___surface.html
print("not implemented")
def adaptor(self):
if self._adaptor is not None and not self.is_dirty:
pass
else:
self._adaptor = BRepAdaptor_Surface(self)
self._adaptor_handle = BRepAdaptor_HSurface()
self._adaptor_handle.Set(self._adaptor)
return self._adaptor
def recognize_face(a_face):
""" Takes a TopoDS shape and tries to identify its nature
whether it is a plane a cylinder a torus etc.
if a plane, returns the normal
if a cylinder, returns the radius
"""
if not type(a_face) is TopoDS_Face:
print("Please hit the 'G' key to switch to face selection mode")
return False
surf = BRepAdaptor_Surface(a_face, True)
surf_type = surf.GetType()
if surf_type == GeomAbs_Plane:
print("Identified Plane Geometry")
# look for the properties of the plane
# first get the related gp_Pln
gp_pln = surf.Plane()
location = gp_pln.Location() # a point of the plane
normal = gp_pln.Axis().Direction() # the plane normal
# then export location and normal to the console output
print("--> Location (global coordinates)", location.X(), location.Y(),
location.Z())
print("--> Normal (global coordinates)", normal.X(), normal.Y(),
normal.Z())
elif surf_type == GeomAbs_Cylinder:
print("Identified Cylinder Geometry")
# look for the properties of the cylinder
# first get the related gp_Cyl
gp_cyl = surf.Cylinder()
location = gp_cyl.Location() # a point of the axis
axis = gp_cyl.Axis().Direction() # the cylinder axis
# then export location and normal to the console output
print("--> Location (global coordinates)", location.X(), location.Y(),
location.Z())
print("--> Axis (global coordinates)", axis.X(), axis.Y(), axis.Z())
elif surf_type == GeomAbs_BSplineSurface:
print("Identified BSplineSurface Geometry")
#gp_bsrf = surf.Surface()
#degree = gp_bsrf.NbUKnots()
# TODO use a model that provided BSplineSurfaces, as1_pe_203.stp only contains
# planes and cylinders
else:
# TODO there are plenty other type that can be checked
# see documentation for the BRepAdaptor class
# https://www.opencascade.com/doc/occt-6.9.1/refman/html/class_b_rep_adaptor___surface.html
print(surf_type, "recognition not implemented")
def by_face(cls, face, restrict=True):
"""
Create by a face.
:param afem.topology.entities.Face face: The face.
:param bool restrict: Option to restruct the uv-domain of the surface
to the boundary of the face.
:return: The adaptor surface.
:rtype: afem.adaptor.entities.FaceAdaptorSurface
"""
adp_srf = BRepAdaptor_Surface(face.object, restrict)
return cls(adp_srf)
def cast_surface(cls, shape, expected_type=None):
""" Attempt to cast the shape (a face) to a surface
Parameters
----------
shape: TopoDS_Face
The shape to cast
expected_type: GeomAbs_SurfaceType
The type to restrict
Returns
-------
surface: BRepAdaptor_Surface or None
The surface or None if it could not be created or did not
match the expected type (if given).
"""
if isinstance(shape, TopoDS_Face):
face = shape
else:
face = TopoDS.Face_(shape)
surface = BRepAdaptor_Surface(face, True)
if expected_type is not None and surface.GetType() != expected_type:
return None
return surface
# conversion to a nurbs representation
nurbs_converter = BRepBuilderAPI_NurbsConvert(base_shape, True)
#nurbs_converter.Perform()
converted_shape = nurbs_converter.Shape()
# now, all edges should be BSpline curves and surfaces BSpline surfaces
# see https://www.opencascade.com/doc/occt-7.4.0/refman/html/class_b_rep_builder_a_p_i___nurbs_convert.html#details
expl = TopologyExplorer(converted_shape)
# loop over faces
fc_idx = 1
for face in expl.faces():
print("=== Face %i ===" % fc_idx)
surf = BRepAdaptor_Surface(face, True)
surf_type = surf.GetType()
# check each of the is a BSpline surface
# it should be, since we used the nurbs converter before
if not surf_type == GeomAbs_BSplineSurface:
raise AssertionError("the face was not converted to a GeomAbs_BSplineSurface")
# get the nurbs
bsrf = surf.BSpline()
print("UDegree:", bsrf.UDegree())
print("VDegree:", bsrf.VDegree())
# uknots array
uknots = bsrf.UKnots()
print("Uknots:", end="")
for i in range(bsrf.NbUKnots()):
print(uknots.Value(i + 1), end=" ")
# vknots array