def rebuild_wing_solid(srfs, divide_closed=True, reloft=False, tol=0.01):
"""
Rebuild a solid shape from the OpenVSP wing surface(s). If only one
surface is provided then it is assumed that a single surface models the
OML and it will be split and modified at the root, tip, and trailing
edge. This single surface should have similar form and
parametrization as the original OpenVSP surface. If more than once
surface is provided then it is assumed that the surfaces were split
during OpenVSP export and are simply sewn together to form the solid.
:param srfs: The wing surface(s) used to rebuild the solid.
:type srfs: collections.Sequence(afem.geometry.entities.Surface)
:param bool divide_closed: Option to divide closed faces.
:param bool reloft: For wings that are not split, this option will
extract isocurves at each spanwise cross section, tessellate the
curve using *tol*, and then approximate the section using a C1
continuous curve. These curves are then used to generate a new
wing surface. This method is experimental.
:param float tol: Tolerance for approximation if
*bspline_restrict* or *reloft* is *True*.
:return: The new solid.
:rtype: afem.topology.entities.Solid
:raise ValueError: If no surfaces are provided.
"""
faces = [Face.by_surface(s) for s in srfs]
compound = Compound.by_shapes(faces)
nsrfs = len(srfs)
if nsrfs == 1:
solid, _ = _process_unsplit_wing(compound, divide_closed, reloft,
tol)
return solid
elif nsrfs > 1:
solid, _ = _build_solid(compound, divide_closed)
return solid
else:
raise ValueError('No surfaces provided.')
def _process_unsplit_wing(compound, divide_closed, reloft, tol):
# Process a wing that was generated without "Split Surfs" option.
faces = compound.faces
if len(faces) != 1:
return None, None
face = faces[0]
# Get the surface.
master_surf = face.surface
# master_surf = NurbsSurface(master_surf.object)
uknots, vknots = master_surf.uknots, master_surf.vknots
vsplit = master_surf.local_to_global_param('v', 0.5)
# Segment off the end caps and the trailing edges.
u1, u2 = uknots[1], uknots[-2]
v1, v2 = vknots[1], vknots[-2]
s1 = master_surf.copy()
s1.segment(u1, u2, v1, v2)
# Reloft the surface by tessellating a curve at each spanwise knot. This
# enforces C1 continuity but assumes linear spanwise wing which may not
# support blending wing sections in newer versions of OpenVSP. Also, since
# the tessellated curves may not match up to the wing end caps making
# sewing unreliable, flat end caps are assumed.
if reloft:
s1 = _reloft_wing_surface(s1, tol)
# Generate new flat end caps using isocurves at the root and tip of
# this new surface
c0 = s1.v_iso(s1.v1)
c1 = s1.v_iso(s1.v2)
e0 = Edge.by_curve(c0)
e1 = Edge.by_curve(c1)
w0 = Wire.by_edge(e0)
w1 = Wire.by_edge(e1)
f0 = Face.by_wire(w0)
f1 = Face.by_wire(w1)
# Make faces of surfaces
f = Face.by_surface(s1)
new_faces = [f, f0, f1]
else:
# Reparamterize knots in spanwise direction to be chord length instead
# of uniform. Use isocurve at quarter-chord to determine knot values.
# This only works as long as surfaces are linear.
c0 = s1.u_iso(s1.u1)
c0.segment(vsplit, c0.u2)
qc_u = PointFromParameter(c0, vsplit, 0.25 * c0.length).parameter
c = s1.v_iso(qc_u)
pnts = [c.eval(u) for u in c.knots]
new_uknots = geom_utils.chord_parameters(pnts, 0., 1.)
s1.set_uknots(new_uknots)
# Segment off end caps
u1, u2 = uknots[0], uknots[1]
v1, v2 = vknots[1], vsplit
s2 = master_surf.copy()
s2.segment(u1, u2, v1, v2)
u1, u2 = uknots[0], uknots[1]
v1, v2 = vsplit, vknots[-2]
s3 = master_surf.copy()
s3.segment(u1, u2, v1, v2)
u1, u2 = uknots[-2], uknots[-1]
v1, v2 = vknots[1], vsplit
s4 = master_surf.copy()
s4.segment(u1, u2, v1, v2)
u1, u2 = uknots[-2], uknots[-1]
v1, v2 = vsplit, vknots[-2]
s5 = master_surf.copy()
s5.segment(u1, u2, v1, v2)
# Make faces of surfaces
new_faces = []
for s in [s1, s2, s3, s4, s5]:
f = Face.by_surface(s)
new_faces.append(f)
# Segment off TE.
u1, u2 = uknots[0], uknots[-1]
v1, v2 = vknots[0], vknots[1]
s6 = master_surf.copy()
s6.segment(u1, u2, v1, v2)
u1, u2 = uknots[0], uknots[-1]
v1, v2 = vknots[-2], vknots[-1]
s7 = master_surf.copy()
s7.segment(u1, u2, v1, v2)
# Split the TE surface at each u-knot.
usplits = occ_utils.to_tcolstd_hseq_real(uknots[1:-1])
split = ShapeUpgrade_SplitSurface()
split.Init(s6.object)
split.SetUSplitValues(usplits)
split.Perform()
comp_surf1 = split.ResSurfaces()
split = ShapeUpgrade_SplitSurface()
split.Init(s7.object)
split.SetUSplitValues(usplits)
split.Perform()
comp_surf2 = split.ResSurfaces()
# For each patch in the composite surfaces create a face.
for i in range(1, comp_surf1.NbUPatches() + 1):
for j in range(1, comp_surf1.NbVPatches() + 1):
hpatch = comp_surf1.Patch(i, j)
f = BRepBuilderAPI_MakeFace(hpatch, 0.).Face()
new_faces.append(f)
for i in range(1, comp_surf2.NbUPatches() + 1):
for j in range(1, comp_surf2.NbVPatches() + 1):
hpatch = comp_surf2.Patch(i, j)
f = BRepBuilderAPI_MakeFace(hpatch, 0.).Face()
new_faces.append(f)
# Put all faces into a compound a generate solid.
new_compound = Compound.by_shapes(new_faces)
return _build_solid(new_compound, divide_closed)