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0032837: Documentation, Geom_Surface - add references to GeomLib::NormEstim() for Normal computations

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References to GeomLib::NormEstim() have been put to Geom_Surface, Adaptor3d_Surface and BRepAdaptor_Surface.
Improved documentation of GeomLib::NormEstim().
This commit is contained in:
kgv
2022-03-02 08:58:10 +03:00
committed by smoskvin
parent b9a372bbcd
commit a9e5f65041
5 changed files with 218 additions and 194 deletions
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236
src/GeomLib/GeomLib.cxx
View File

@@ -2371,119 +2371,143 @@ void GeomLib::CancelDenominatorDerivative(Handle(Geom_BSplineSurface) &
//=======================================================================
//function : NormEstim
//purpose :
//purpose :
//=======================================================================
Standard_Integer GeomLib::NormEstim(const Handle(Geom_Surface)& S,
const gp_Pnt2d& UV,
const Standard_Real Tol, gp_Dir& N)
Standard_Integer GeomLib::NormEstim (const Handle(Geom_Surface)& theSurf,
const gp_Pnt2d& theUV,
const Standard_Real theTol,
gp_Dir& theNorm)
{
const Standard_Real aTol2 = Square (theTol);
gp_Vec DU, DV;
gp_Pnt DummyPnt;
Standard_Real aTol2 = Square(Tol);
gp_Pnt aDummyPnt;
theSurf->D1 (theUV.X(), theUV.Y(), aDummyPnt, DU, DV);
S->D1(UV.X(), UV.Y(), DummyPnt, DU, DV);
Standard_Real MDU = DU.SquareMagnitude(), MDV = DV.SquareMagnitude();
if(MDU >= aTol2 && MDV >= aTol2) {
gp_Vec Norm = DU^DV;
Standard_Real Magn = Norm.SquareMagnitude();
if(Magn < aTol2) return 3;
//Magn = sqrt(Magn);
N.SetXYZ(Norm.XYZ());
return 0;
}
else {
gp_Vec D2U, D2V, D2UV;
Standard_Boolean isDone;
CSLib_NormalStatus aStatus;
gp_Dir aNormal;
S->D2(UV.X(), UV.Y(), DummyPnt, DU, DV, D2U, D2V, D2UV);
CSLib::Normal(DU, DV, D2U, D2V, D2UV, Tol, isDone, aStatus, aNormal);
if (isDone) {
Standard_Real Umin, Umax, Vmin, Vmax;
Standard_Real step = 1.0e-5;
Standard_Real eps = 1.0e-16;
Standard_Real sign = -1.0;
S->Bounds(Umin, Umax, Vmin, Vmax);
// check for cone apex singularity point
if ((UV.Y() > Vmin + step) && (UV.Y() < Vmax - step))
{
gp_Dir aNormal1, aNormal2;
Standard_Real aConeSingularityAngleEps = 1.0e-4;
S->D1(UV.X(), UV.Y() - sign * step, DummyPnt, DU, DV);
if ((DU.XYZ().SquareModulus() > eps) && (DV.XYZ().SquareModulus() > eps)) {
aNormal1 = DU^DV;
S->D1(UV.X(), UV.Y() + sign * step, DummyPnt, DU, DV);
if ((DU.XYZ().SquareModulus() > eps) && (DV.XYZ().SquareModulus() > eps)) {
aNormal2 = DU^DV;
if (aNormal1.IsOpposite(aNormal2, aConeSingularityAngleEps))
return 2;
}
}
}
// Along V
if(MDU < aTol2 && MDV >= aTol2) {
if ((Vmax - UV.Y()) > (UV.Y() - Vmin))
sign = 1.0;
S->D1(UV.X(), UV.Y() + sign * step, DummyPnt, DU, DV);
gp_Vec Norm = DU^DV;
if (Norm.SquareMagnitude() < eps) {
Standard_Real sign1 = -1.0;
if ((Umax - UV.X()) > (UV.X() - Umin))
sign1 = 1.0;
S->D1(UV.X() + sign1 * step, UV.Y() + sign * step, DummyPnt, DU, DV);
Norm = DU^DV;
}
if ((Norm.SquareMagnitude() >= eps) && (Norm.Dot(aNormal) < 0.0))
aNormal.Reverse();
}
// Along U
if(MDV < aTol2 && MDU >= aTol2) {
if ((Umax - UV.X()) > (UV.X() - Umin))
sign = 1.0;
S->D1(UV.X() + sign * step, UV.Y(), DummyPnt, DU, DV);
gp_Vec Norm = DU^DV;
if (Norm.SquareMagnitude() < eps) {
Standard_Real sign1 = -1.0;
if ((Vmax - UV.Y()) > (UV.Y() - Vmin))
sign1 = 1.0;
S->D1(UV.X() + sign * step, UV.Y() + sign1 * step, DummyPnt, DU, DV);
Norm = DU^DV;
}
if ((Norm.SquareMagnitude() >= eps) && (Norm.Dot(aNormal) < 0.0))
aNormal.Reverse();
}
// quasysingular
if ((aStatus == CSLib_D1NuIsNull) || (aStatus == CSLib_D1NvIsNull) ||
(aStatus == CSLib_D1NuIsParallelD1Nv)) {
N.SetXYZ(aNormal.XYZ());
return 1;
}
// conical
if (aStatus == CSLib_InfinityOfSolutions)
return 2;
}
// computation is impossible
else {
// conical
if (aStatus == CSLib_D1NIsNull) {
return 2;
}
const Standard_Real MDU = DU.SquareMagnitude(), MDV = DV.SquareMagnitude();
if (MDU >= aTol2
&& MDV >= aTol2)
{
gp_Vec aNorm = DU ^ DV;
Standard_Real aMagn = aNorm.SquareMagnitude();
if (aMagn < aTol2)
{
return 3;
}
theNorm.SetXYZ (aNorm.XYZ());
return 0;
}
return 3;
gp_Vec D2U, D2V, D2UV;
Standard_Boolean isDone = false;
CSLib_NormalStatus aStatus;
gp_Dir aNormal;
theSurf->D2 (theUV.X(), theUV.Y(), aDummyPnt, DU, DV, D2U, D2V, D2UV);
CSLib::Normal (DU, DV, D2U, D2V, D2UV, theTol, isDone, aStatus, aNormal);
if (!isDone)
{
// computation is impossible
return aStatus == CSLib_D1NIsNull ? 2 : 3;
}
Standard_Real Umin, Umax, Vmin, Vmax;
Standard_Real step = 1.0e-5;
Standard_Real eps = 1.0e-16;
Standard_Real sign = -1.0;
theSurf->Bounds (Umin, Umax, Vmin, Vmax);
// check for cone apex singularity point
if ((theUV.Y() > Vmin + step)
&& (theUV.Y() < Vmax - step))
{
gp_Dir aNormal1, aNormal2;
Standard_Real aConeSingularityAngleEps = 1.0e-4;
theSurf->D1(theUV.X(), theUV.Y() - sign * step, aDummyPnt, DU, DV);
if ((DU.XYZ().SquareModulus() > eps) && (DV.XYZ().SquareModulus() > eps))
{
aNormal1 = DU ^ DV;
theSurf->D1 (theUV.X(), theUV.Y() + sign * step, aDummyPnt, DU, DV);
if ((DU.XYZ().SquareModulus() > eps)
&& (DV.XYZ().SquareModulus() > eps))
{
aNormal2 = DU^DV;
if (aNormal1.IsOpposite (aNormal2, aConeSingularityAngleEps))
{
return 2;
}
}
}
}
// Along V
if (MDU < aTol2
&& MDV >= aTol2)
{
if ((Vmax - theUV.Y()) > (theUV.Y() - Vmin))
{
sign = 1.0;
}
theSurf->D1 (theUV.X(), theUV.Y() + sign * step, aDummyPnt, DU, DV);
gp_Vec Norm = DU ^ DV;
if (Norm.SquareMagnitude() < eps)
{
Standard_Real sign1 = -1.0;
if ((Umax - theUV.X()) > (theUV.X() - Umin))
{
sign1 = 1.0;
}
theSurf->D1 (theUV.X() + sign1 * step, theUV.Y() + sign * step, aDummyPnt, DU, DV);
Norm = DU ^ DV;
}
if (Norm.SquareMagnitude() >= eps
&& Norm.Dot (aNormal) < 0.0)
{
aNormal.Reverse();
}
}
// Along U
if (MDV < aTol2
&& MDU >= aTol2)
{
if ((Umax - theUV.X()) > (theUV.X() - Umin))
{
sign = 1.0;
}
theSurf->D1 (theUV.X() + sign * step, theUV.Y(), aDummyPnt, DU, DV);
gp_Vec Norm = DU ^ DV;
if (Norm.SquareMagnitude() < eps)
{
Standard_Real sign1 = -1.0;
if ((Vmax - theUV.Y()) > (theUV.Y() - Vmin))
{
sign1 = 1.0;
}
theSurf->D1 (theUV.X() + sign * step, theUV.Y() + sign1 * step, aDummyPnt, DU, DV);
Norm = DU ^ DV;
}
if (Norm.SquareMagnitude() >= eps
&& Norm.Dot (aNormal) < 0.0)
{
aNormal.Reverse();
}
}
// quasysingular
if (aStatus == CSLib_D1NuIsNull
|| aStatus == CSLib_D1NvIsNull
|| aStatus == CSLib_D1NuIsParallelD1Nv)
{
theNorm.SetXYZ (aNormal.XYZ());
return 1;
}
return aStatus == CSLib_InfinityOfSolutions ? 2 : 3;
}
//=======================================================================

15
src/GeomLib/GeomLib.hxx
View File

@@ -183,8 +183,19 @@ public:
//! Cancel,on the boundaries,the denominator first derivative
//! in the directions wished by the user and set its value to 1.
Standard_EXPORT static void CancelDenominatorDerivative (Handle(Geom_BSplineSurface)& BSurf, const Standard_Boolean UDirection, const Standard_Boolean VDirection);
Standard_EXPORT static Standard_Integer NormEstim (const Handle(Geom_Surface)& S, const gp_Pnt2d& UV, const Standard_Real Tol, gp_Dir& N);
//! Estimate surface normal at the given (U, V) point.
//! @param[in] theSurf input surface
//! @param[in] theUV (U, V) point coordinates on the surface
//! @param[in] theTol estimation tolerance
//! @param[out] theNorm computed normal
//! @return 0 if normal estimated from D1,
//! 1 if estimated from D2 (quasysingular),
//! >=2 in case of failure (undefined or infinite solutions)
Standard_EXPORT static Standard_Integer NormEstim (const Handle(Geom_Surface)& theSurf,
const gp_Pnt2d& theUV,
const Standard_Real theTol,
gp_Dir& theNorm);
//! This method defines if opposite boundaries of surface
//! coincide with given tolerance