def second_derivative(h_surf, u=0, v=0):
p1 = gp_Pnt()
pu, pv = gp_Vec(), gp_Vec()
puu, pvv = gp_Vec(), gp_Vec()
puv = gp_Vec()
prop = GeomLProp_SLProps(h_surf, u, v, 1, 1)
GeomLProp_SurfaceTool.D2(h_surf, u, v, p1, pu, pv, puu, pvv, puv)
e0 = pu.Crossed(pv)
pu.Normalize()
pv.Normalize()
e0.Normalize()
puu.Normalize()
pvv.Normalize()
puv.Normalize()
print(p1)
print("pu", pu)
print("pv", pv)
print("e0", e0)
print("puu", puu)
print("pvv", pvv)
print("puv", puv)
first_form = np.array([[pu.Dot(pu), pu.Dot(pv)], [pv.Dot(pu), pv.Dot(pv)]])
secnd_form = np.array([[e0.Dot(puu), e0.Dot(puv)],
[e0.Dot(puv), e0.Dot(pvv)]])
print(first_form)
print(secnd_form)
print(prop.GaussianCurvature())
print(prop.MeanCurvature())
d1, d2 = gp_Dir(), gp_Dir()
prop.CurvatureDirections(d1, d2)
a1 = gp_Ax3()
v1 = dir_to_vec(d1)
v2 = dir_to_vec(d2)
if pu.IsParallel(v1, 1 / 1000):
c1 = prop.MaxCurvature()
c2 = prop.MinCurvature()
print(v1.Dot(pu), v1.Dot(pv))
print(v2.Dot(pu), v2.Dot(pv))
else:
c1 = prop.MinCurvature()
c2 = prop.MaxCurvature()
print(v1.Dot(pu), v1.Dot(pv))
print(v2.Dot(pu), v2.Dot(pv))
print(c1, 1 / c1)
print(c2, 1 / c2)
px = np.linspace(-1, 1, 100) * 100
p1_y = px**2 / c1
p2_y = px**2 / c1
curv1 = curv_spl(px, p1_y)
curv2 = curv_spl(px, p2_y)
def radius_at_uv(face, u, v):
'''
returns the mean radius at a u,v coordinate
@param face: surface input
@param u,v: u,v coordinate
'''
h_srf = BRep_Tool().Surface(face)
uv_domain = GeomLProp_SurfaceTool().Bounds(h_srf)
curvature = GeomLProp_SLProps(h_srf, u, v, 1, 1e-6)
try:
_crv_min = 1. / curvature.MinCurvature()
except ZeroDivisionError:
_crv_min = 0.
try:
_crv_max = 1. / curvature.MaxCurvature()
except ZeroDivisionError:
_crv_max = 0.
return abs((_crv_min + _crv_max) / 2.)