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Fix a problem with wrong curvature values

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This commit is contained in:
jfa 2022-08-04 00:54:59 +03:00
parent 6f7a37a47b
commit 55e7a4baa5
2 changed files with 41 additions and 38 deletions
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11
doc/salome/examples/curvature_face.py
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@ -29,14 +29,19 @@ Sphere_1 = geompy.MakeSphereR(R, 'Sphere_1')
curvature_1 = geompy.CurvatureOnFace(Sph, pXYZ, OX, 'curvature_sph_pXYZ_OX') curvature_1 = geompy.CurvatureOnFace(Sph, pXYZ, OX, 'curvature_sph_pXYZ_OX')
curvature_2 = geompy.CurvatureOnFace(Sph, pXYZ, vZ_XY, 'curvature_sph_pXYZ_vt') curvature_2 = geompy.CurvatureOnFace(Sph, pXYZ, vZ_XY, 'curvature_sph_pXYZ_vt')
curvature_3 = geompy.CurvatureOnFace(Sph, pY, OX, 'curvature_sph_pY_OX') curvature_3 = geompy.CurvatureOnFace(Sph, pY, OX, 'curvature_sph_pY_OX')
# Pole
curvature_p = geompy.CurvatureOnFace(Sph, pZ, OX, 'curvature_sph_pZ_OX')
# All sphere curvature radiuces = R # All sphere curvature radiuces = R
assert(abs(geompy.BasicProperties(curvature_1)[0] - R) < 1e-07) assert(abs(geompy.BasicProperties(curvature_1)[0] - R) < 1e-07)
assert(abs(geompy.BasicProperties(curvature_2)[0] - R) < 1e-07) assert(abs(geompy.BasicProperties(curvature_2)[0] - R) < 1e-07)
assert(abs(geompy.BasicProperties(curvature_3)[0] - R) < 1e-07) assert(abs(geompy.BasicProperties(curvature_3)[0] - R) < 1e-07)
assert(abs(geompy.BasicProperties(curvature_p)[0] - R) < 1e-07)
# Pole
isExcept = False
try:
geompy.CurvatureOnFace(Sph, pZ, OX)
except:
isExcept = True
assert(isExcept)
# Normal direction # Normal direction
isExcept = False isExcept = False

68
src/GEOMImpl/GEOMImpl_MeasureDriver.cxx
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@ -118,49 +118,47 @@ TopoDS_Shape EvaluateAlongCurvature(const TopoDS_Shape& theFace,
("Curvature calculation failed: normal direction is not defined"); ("Curvature calculation failed: normal direction is not defined");
// Get differential properties // Get differential properties
gp_Vec Xu = Props.D1U(); gp_Vec n = Props.Normal();
gp_Vec Xv = Props.D1V(); if (aV.IsParallel(n, Precision::Angular()))
gp_Vec Xuu = Props.D2U();
gp_Vec Xuv = Props.DUV();
gp_Vec Xvv = Props.D2V();
gp_Vec n = Props.Normal();
// Direction in 2d
gp_Dir aDirU (Xu);
gp_Dir aDirV (Xv);
gp_Vec2d T (aV.Dot(aDirU), aV.Dot(aDirV));
if (Abs(T.X()) < Precision::Confusion() &&
Abs(T.Y()) < Precision::Confusion())
Standard_ConstructionError::Raise Standard_ConstructionError::Raise
("Curvature calculation failed: direction is normal to the face"); ("Curvature calculation failed: direction is normal to the face");
// Coefficients of the FFF if (!Props.IsCurvatureDefined())
double E = Xu.Dot(Xu); Standard_ConstructionError::Raise
double F = Xu.Dot(Xv); ("Curvature calculation failed: curvature is not defined");
double G = Xv.Dot(Xv);
// Coefficients of the SFF // Curvature
double L = n.Dot(Xuu); Standard_Real k = 0.;
double M = n.Dot(Xuv);
double N = n.Dot(Xvv);
// Calculate radius (or -radius) of curvature if (Props.IsUmbilic()) {
// using the coefficients of both fundamental forms k = Props.MaxCurvature();
double r = 0.;
if (Abs(T.X()) < Precision::Confusion()) {
if (Abs(N) < Precision::Confusion())
Standard_Failure::Raise("ZERO_CURVATURE");
r = G / N;
} }
else { else {
double lambda = T.Y() / T.X(); gp_Dir aMaxDir, aMinDir;
double detE = E + 2*F*lambda + G*lambda*lambda; Props.CurvatureDirections(aMaxDir, aMinDir);
double detL = L + 2*M*lambda + N*lambda*lambda;
if (Abs(detL) < Precision::Confusion()) gp_Vec2d T (aV.Dot(aMinDir), aV.Dot(aMaxDir));
Standard_Failure::Raise("ZERO_CURVATURE"); if (Abs(T.X()) < Precision::Confusion() &&
r = detE / detL; Abs(T.Y()) < Precision::Confusion())
Standard_ConstructionError::Raise
("Curvature calculation failed: direction is normal to the face");
gp_Dir2d aDirT (T);
Standard_Real cosAlpha = aDirT.X();
Standard_Real aMinCurv = Props.MinCurvature();
Standard_Real aMaxCurv = Props.MaxCurvature();
// Euler formula: k = k1 * cos^2(alpha) + k2 * sin^2(alpha)
// k = k2 + (k1 - k2) * cos^2(alpha)
k = aMaxCurv + (aMinCurv - aMaxCurv) * cosAlpha * cosAlpha;
} }
if (Abs(k) < Precision::Confusion())
Standard_Failure::Raise("ZERO_CURVATURE");
// Radius or -radius of curvature
Standard_Real r = 1.0 / k;
// Result // Result
gp_Dir aNormal (n); gp_Dir aNormal (n);
gp_Pnt aPntEnd (aPnt.XYZ() + aNormal.XYZ() * r); gp_Pnt aPntEnd (aPnt.XYZ() + aNormal.XYZ() * r);