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("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()
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)
print("not implemented")
def project_mesh_to_cad_3d(mesh, cad):
from OCC.Core.BRepAdaptor import BRepAdaptor_Surface, BRepAdaptor_Curve
from OCC.Core.gp import gp_Pnt
from OCC.Core.GeomAPI import GeomAPI_ProjectPointOnSurf, GeomAPI_ProjectPointOnCurve
coorddata = mesh.coordinates.dat.data
ids = mesh.exterior_facets.unique_markers
filt = lambda arr: arr[numpy.where(arr < mesh.coordinates.dof_dset.size)[0]
]
boundary_nodes = {
id: filt(mesh.coordinates.function_space().boundary_nodes(
int(id), "topological"))
for id in ids
}
for (id, face) in zip(ids, cad.faces()):
owned_nodes = boundary_nodes[id]
for other_id in ids:
if id == other_id:
continue
owned_nodes = numpy.setdiff1d(owned_nodes,
boundary_nodes[other_id])
surf = BRepAdaptor_Surface(face)
for node in owned_nodes:
pt = gp_Pnt(*coorddata[node, :])
proj = GeomAPI_ProjectPointOnSurf(pt, surf.Surface().Surface())
if proj.NbPoints() > 0:
projpt = proj.NearestPoint()
coorddata[node, :] = projpt.Coord()
else:
warnings.warn("Projection of point %s onto face %d failed" %
(coorddata[node, :], id))
edges = set(cad.edges_from_face(face))
for (other_id, other_face) in zip(ids, cad.faces()):
if other_id <= id:
continue
intersecting_nodes = numpy.intersect1d(boundary_nodes[id],
boundary_nodes[other_id])
if len(intersecting_nodes) == 0:
continue
other_edges = set(cad.edges_from_face(other_face))
intersecting_edges = []
for edge in edges:
s = str(
edge
) # FIXME: is there a more elegant way to get the OCC id?
for other_edge in other_edges:
other_s = str(other_edge)
if s == other_s:
intersecting_edges.append(edge)
if len(intersecting_edges) == 0:
warnings.warn(
"face: %s other_face: %s intersecting_edges: %s" %
(face, other_face, intersecting_edges))
warnings.warn(
"Warning: no intersecting edges in CAD, even though vertices on both faces?"
)
continue
for node in intersecting_nodes:
pt = gp_Pnt(*coorddata[node, :])
projections = []
for edge in intersecting_edges:
curve = BRepAdaptor_Curve(edge)
proj = GeomAPI_ProjectPointOnCurve(pt,
curve.Curve().Curve())
if proj.NbPoints() > 0:
projpt = proj.NearestPoint()
sqdist = projpt.SquareDistance(pt)
projections.append((projpt, sqdist))
else:
warnings.warn(
"Projection of point %s onto curve failed" %
coorddata[node, :])
(projpt, sqdist) = min(projections, key=lambda x: x[1])
coorddata[node, :] = projpt.Coord()