# correct test cases

Let's we have a spline having fit points located on a direct line (let's number them 1, 2, 3), but they are located in order 1, 3, 2. There was a bug in GCPnts_TangentialDeflection that only first and last points were put in the result. Now more point is put, so that the result polygon made back movement.

The command crvtpoints has been made to accept angular value in degrees instead of radians.

src/BRepMesh/BRepMesh_DiscretFactory.hxx

@@ -89,9 +89,11 @@ public:
   //! @param theShape shape to be meshed.
   //! @param theLinDeflection linear deflection to be used for meshing.
   //! @param theAngDeflection angular deflection to be used for meshing.
+  //! @param theTDOldBehavior tangential deflection behavior for default algorithm.
   Standard_EXPORT Handle(BRepMesh_DiscretRoot) Discret(const TopoDS_Shape& theShape,
                                                        const Standard_Real theLinDeflection,
-                                                       const Standard_Real theAngDeflection);
+                                                       const Standard_Real theAngDeflection,
+                                                       const Standard_Boolean theTDOldBehavior = Standard_True);
 
 protected:
   

src/BRepMesh/BRepMesh_FastDiscret.hxx

@@ -68,7 +68,8 @@ public:
      Relative(Standard_False),
      AdaptiveMin(Standard_False),
      InternalVerticesMode(Standard_True),
-     ControlSurfaceDeflection(Standard_True)
+     ControlSurfaceDeflection(Standard_True),
+     TDOldBehavior(Standard_True)
      {
      }
     
@@ -103,6 +104,10 @@ public:
     //! Prameter to check the deviation of triangulation and interior of
     //! the face
     Standard_Boolean                                 ControlSurfaceDeflection;
+
+    //! Prameter to set tangential deflection behavior
+    //! (old - for backward compatibility, may produce incorrect results in several cases)
+    Standard_Boolean                                 TDOldBehavior;
   };
 
 public:

src/BRepMesh/BRepMesh_IncrementalMesh.cxx

@@ -84,7 +84,8 @@ BRepMesh_IncrementalMesh::BRepMesh_IncrementalMesh( const TopoDS_Shape&    theSh
                                                     const Standard_Boolean isRelative,
                                                     const Standard_Real    theAngDeflection,
                                                     const Standard_Boolean isInParallel,
-                                                    const Standard_Boolean adaptiveMin)
+                                                    const Standard_Boolean adaptiveMin,
+                                                    const Standard_Boolean theTdOldBehavior)
 : myMaxShapeSize(0.),
   myModified(Standard_False),
   myStatus(0)
@@ -94,6 +95,7 @@ BRepMesh_IncrementalMesh::BRepMesh_IncrementalMesh( const TopoDS_Shape&    theSh
   myParameters.Angle = theAngDeflection;
   myParameters.InParallel = isInParallel;
   myParameters.AdaptiveMin = adaptiveMin;
+  myParameters.TDOldBehavior = theTdOldBehavior;
 
   myShape = theShape;
   Perform();
@@ -262,7 +264,7 @@ void BRepMesh_IncrementalMesh::discretizeFreeEdges()
     BRepAdaptor_Curve aCurve(aEdge);
     GCPnts_TangentialDeflection aDiscret(aCurve, aCurve.FirstParameter(),
       aCurve.LastParameter(), myParameters.Angle, aEdgeDeflection, 2,
-      Precision::PConfusion(), myParameters.MinSize);
+      Precision::PConfusion(), myParameters.MinSize, myParameters.TDOldBehavior);
 
     Standard_Integer aNodesNb = aDiscret.NbPoints();
     TColgp_Array1OfPnt   aNodes  (1, aNodesNb);
@@ -572,6 +574,23 @@ Standard_Integer BRepMesh_IncrementalMesh::Discret(
   return 0; // no error
 }
 
+Standard_Integer BRepMesh_IncrementalMesh::Discret(
+  const TopoDS_Shape&    theShape,
+  const Standard_Real    theDeflection,
+  const Standard_Real    theAngle,
+  const Standard_Boolean theTdOldBehavior,
+  BRepMesh_DiscretRoot* &theAlgo)
+{
+    BRepMesh_IncrementalMesh* anAlgo = new BRepMesh_IncrementalMesh();
+    anAlgo->ChangeParameters().Deflection = theDeflection;
+    anAlgo->ChangeParameters().Angle = theAngle;
+    anAlgo->ChangeParameters().InParallel = IS_IN_PARALLEL;
+    anAlgo->ChangeParameters().TDOldBehavior = theTdOldBehavior;
+    anAlgo->SetShape(theShape);
+    theAlgo = anAlgo;
+    return 0; // no error
+}
+
 //=======================================================================
 //function : IsParallelDefault
 //purpose  :

src/BRepMesh/BRepMesh_IncrementalMesh.hxx

@@ -57,7 +57,8 @@ public: //! @name mesher API
     const Standard_Boolean isRelative = Standard_False,
     const Standard_Real    theAngDeflection = 0.5,
     const Standard_Boolean isInParallel = Standard_False,
-    const Standard_Boolean adaptiveMin = Standard_False);  
+    const Standard_Boolean adaptiveMin = Standard_False,
+    const Standard_Boolean theTdOldBehavior = Standard_True);
 
   //! Constructor.
   //! Automatically calls method Perform.
@@ -108,6 +109,19 @@ public: //! @name plugin API
                                                   const Standard_Real    theLinDeflection,
                                                   const Standard_Real    theAngDeflection,
                                                   BRepMesh_DiscretRoot* &theAlgo);
+
+  //! Plugin interface for the Mesh Factories.
+  //! Initializes meshing algorithm with the given parameters.
+  //! @param theShape shape to be meshed.
+  //! @param theLinDeflection linear deflection.
+  //! @param theAngDeflection angular deflection.
+  //! @param theTdOldBehavior angle comparison mode for tangential deflection
+  //! @param[out] theAlgo pointer to initialized algorithm.
+  Standard_EXPORT static Standard_Integer Discret(const TopoDS_Shape&    theShape,
+                                                  const Standard_Real    theLinDeflection,
+                                                  const Standard_Real    theAngDeflection,
+                                                  const Standard_Boolean theTdOldBehavior,
+                                                  BRepMesh_DiscretRoot* &theAlgo);
   
   //! Returns multi-threading usage flag set by default in 
   //! Discret() static method (thus applied only to Mesh Factories).

src/GCPnts/GCPnts_TangentialDeflection.cxx

@@ -67,11 +67,26 @@ static void D2 (const Adaptor2d_Curve2d& C, const Standard_Real U,
 static Standard_Real EstimAngl(const gp_Pnt& P1, const gp_Pnt& Pm, const gp_Pnt& P2)
 {
   gp_Vec V1(P1, Pm), V2(Pm, P2);
-  Standard_Real L = V1.Magnitude() * V2.Magnitude();
+  Standard_Real L = Sqrt(V1.SquareMagnitude() * V2.SquareMagnitude());
   //
   if(L > gp::Resolution())
   {
-    return V1.CrossMagnitude(V2)/L;
+    return V1.Dot(V2) / L;
+  }
+  else
+  {
+    return 0.;
+  }
+}
+
+static Standard_Real EstimAnglOld(const gp_Pnt& P1, const gp_Pnt& Pm, const gp_Pnt& P2)
+{
+    gp_Vec V1(P1, Pm), V2(Pm, P2);
+    Standard_Real L = Sqrt(V1.SquareMagnitude() * V2.SquareMagnitude());
+    //
+    if(L > gp::Resolution())
+    {
+        return V1.CrossMagnitude(V2) / L;
   }
   else
   {

src/GCPnts/GCPnts_TangentialDeflection.hxx

@@ -75,21 +75,21 @@ public:
   
   Standard_EXPORT GCPnts_TangentialDeflection();
   
-  Standard_EXPORT GCPnts_TangentialDeflection(const Adaptor3d_Curve& C, const Standard_Real AngularDeflection, const Standard_Real CurvatureDeflection, const Standard_Integer MinimumOfPoints = 2, const Standard_Real UTol = 1.0e-9, const Standard_Real theMinLen = 1.0e-7);
+  Standard_EXPORT GCPnts_TangentialDeflection(const Adaptor3d_Curve& C, const Standard_Real AngularDeflection, const Standard_Real CurvatureDeflection, const Standard_Integer MinimumOfPoints = 2, const Standard_Real UTol = 1.0e-9, const Standard_Real theMinLen = 1.0e-7, const Standard_Boolean ACompOldBehavior = Standard_False);
   
-  Standard_EXPORT GCPnts_TangentialDeflection(const Adaptor3d_Curve& C, const Standard_Real FirstParameter, const Standard_Real LastParameter, const Standard_Real AngularDeflection, const Standard_Real CurvatureDeflection, const Standard_Integer MinimumOfPoints = 2, const Standard_Real UTol = 1.0e-9, const Standard_Real theMinLen = 1.0e-7);
+  Standard_EXPORT GCPnts_TangentialDeflection(const Adaptor3d_Curve& C, const Standard_Real FirstParameter, const Standard_Real LastParameter, const Standard_Real AngularDeflection, const Standard_Real CurvatureDeflection, const Standard_Integer MinimumOfPoints = 2, const Standard_Real UTol = 1.0e-9, const Standard_Real theMinLen = 1.0e-7, const Standard_Boolean ACompOldBehavior = Standard_False);
   
-  Standard_EXPORT GCPnts_TangentialDeflection(const Adaptor2d_Curve2d& C, const Standard_Real AngularDeflection, const Standard_Real CurvatureDeflection, const Standard_Integer MinimumOfPoints = 2, const Standard_Real UTol = 1.0e-9, const Standard_Real theMinLen = 1.0e-7);
+  Standard_EXPORT GCPnts_TangentialDeflection(const Adaptor2d_Curve2d& C, const Standard_Real AngularDeflection, const Standard_Real CurvatureDeflection, const Standard_Integer MinimumOfPoints = 2, const Standard_Real UTol = 1.0e-9, const Standard_Real theMinLen = 1.0e-7, const Standard_Boolean ACompOldBehavior = Standard_False);
   
-  Standard_EXPORT GCPnts_TangentialDeflection(const Adaptor2d_Curve2d& C, const Standard_Real FirstParameter, const Standard_Real LastParameter, const Standard_Real AngularDeflection, const Standard_Real CurvatureDeflection, const Standard_Integer MinimumOfPoints = 2, const Standard_Real UTol = 1.0e-9, const Standard_Real theMinLen = 1.0e-7);
+  Standard_EXPORT GCPnts_TangentialDeflection(const Adaptor2d_Curve2d& C, const Standard_Real FirstParameter, const Standard_Real LastParameter, const Standard_Real AngularDeflection, const Standard_Real CurvatureDeflection, const Standard_Integer MinimumOfPoints = 2, const Standard_Real UTol = 1.0e-9, const Standard_Real theMinLen = 1.0e-7, const Standard_Boolean ACompOldBehavior = Standard_False);
   
-  Standard_EXPORT void Initialize (const Adaptor3d_Curve& C, const Standard_Real AngularDeflection, const Standard_Real CurvatureDeflection, const Standard_Integer MinimumOfPoints = 2, const Standard_Real UTol = 1.0e-9, const Standard_Real theMinLen = 1.0e-7);
+  Standard_EXPORT void Initialize (const Adaptor3d_Curve& C, const Standard_Real AngularDeflection, const Standard_Real CurvatureDeflection, const Standard_Integer MinimumOfPoints = 2, const Standard_Real UTol = 1.0e-9, const Standard_Real theMinLen = 1.0e-7, const Standard_Boolean ACompOldBehavior = Standard_False);
   
-  Standard_EXPORT void Initialize (const Adaptor3d_Curve& C, const Standard_Real FirstParameter, const Standard_Real LastParameter, const Standard_Real AngularDeflection, const Standard_Real CurvatureDeflection, const Standard_Integer MinimumOfPoints = 2, const Standard_Real UTol = 1.0e-9, const Standard_Real theMinLen = 1.0e-7);
+  Standard_EXPORT void Initialize (const Adaptor3d_Curve& C, const Standard_Real FirstParameter, const Standard_Real LastParameter, const Standard_Real AngularDeflection, const Standard_Real CurvatureDeflection, const Standard_Integer MinimumOfPoints = 2, const Standard_Real UTol = 1.0e-9, const Standard_Real theMinLen = 1.0e-7, const Standard_Boolean ACompOldBehavior = Standard_False);
   
-  Standard_EXPORT void Initialize (const Adaptor2d_Curve2d& C, const Standard_Real AngularDeflection, const Standard_Real CurvatureDeflection, const Standard_Integer MinimumOfPoints = 2, const Standard_Real UTol = 1.0e-9, const Standard_Real theMinLen = 1.0e-7);
+  Standard_EXPORT void Initialize (const Adaptor2d_Curve2d& C, const Standard_Real AngularDeflection, const Standard_Real CurvatureDeflection, const Standard_Integer MinimumOfPoints = 2, const Standard_Real UTol = 1.0e-9, const Standard_Real theMinLen = 1.0e-7, const Standard_Boolean ACompOldBehavior = Standard_False);
   
-  Standard_EXPORT void Initialize (const Adaptor2d_Curve2d& C, const Standard_Real FirstParameter, const Standard_Real LastParameter, const Standard_Real AngularDeflection, const Standard_Real CurvatureDeflection, const Standard_Integer MinimumOfPoints = 2, const Standard_Real UTol = 1.0e-9, const Standard_Real theMinLen = 1.0e-7);
+  Standard_EXPORT void Initialize (const Adaptor2d_Curve2d& C, const Standard_Real FirstParameter, const Standard_Real LastParameter, const Standard_Real AngularDeflection, const Standard_Real CurvatureDeflection, const Standard_Integer MinimumOfPoints = 2, const Standard_Real UTol = 1.0e-9, const Standard_Real theMinLen = 1.0e-7, const Standard_Boolean ACompOldBehavior = Standard_False);
   
   //! Add point to already calculated points (or replace existing)
   //! Returns index of new added point
@@ -110,6 +110,12 @@ public:
   {
     return points.Value (I);
   }
+
+  //! Returns if the old behavior for angle comparison (based on sin) or the new one (based on cos) should be used.
+  Standard_Boolean ACompOldBehavior()
+  {
+      return aCompOldBehavior;
+  }
   
   //! Computes angular step for the arc using the given parameters.
   Standard_EXPORT static Standard_Real ArcAngularStep (const Standard_Real theRadius, const Standard_Real theLinearDeflection, const Standard_Real theAngularDeflection, const Standard_Real theMinLength);
@@ -148,6 +154,7 @@ private:
   Standard_Real firstu;
   TColgp_SequenceOfPnt points;
   TColStd_SequenceOfReal parameters;
+  Standard_Boolean aCompOldBehavior;
 };
 
 #endif // _GCPnts_TangentialDeflection_HeaderFile

src/GCPnts/GCPnts_TangentialDeflection.pxx

@@ -42,7 +42,7 @@ void GCPnts_TangentialDeflection::EvaluateDu (
     Standard_Real Lc = N.CrossMagnitude (T);
     Standard_Real Ln = Lc/Lt;
     if (Ln > LTol) {
-      Du = sqrt (8.0 * Max(curvatureDeflection, myMinLen) / Ln);
+      Du = Sqrt (8.0 * Max(curvatureDeflection, myMinLen) / Ln);
       NotDone = Standard_False;
     }
   }
@@ -60,10 +60,11 @@ GCPnts_TangentialDeflection::GCPnts_TangentialDeflection (
  const Standard_Real    CurvatureDeflection,
  const Standard_Integer MinimumOfPoints,
  const Standard_Real    UTol,
- const Standard_Real    theMinLen)
+ const Standard_Real    theMinLen, 
+ const Standard_Boolean ACompOldBehavior)
 
 { 
-  Initialize (C,AngularDeflection,CurvatureDeflection,MinimumOfPoints,UTol,theMinLen); 
+  Initialize (C,AngularDeflection,CurvatureDeflection,MinimumOfPoints,UTol,theMinLen, ACompOldBehavior);
 }
 
 
@@ -80,7 +81,8 @@ GCPnts_TangentialDeflection::GCPnts_TangentialDeflection (
  const Standard_Real    CurvatureDeflection,
  const Standard_Integer MinimumOfPoints,
  const Standard_Real    UTol,
- const Standard_Real    theMinLen)
+ const Standard_Real    theMinLen,
+ const Standard_Boolean ACompOldBehavior)
 
 { 
   Initialize (C, 
@@ -89,7 +91,8 @@ GCPnts_TangentialDeflection::GCPnts_TangentialDeflection (
         AngularDeflection, 
         CurvatureDeflection, 
         MinimumOfPoints,
-        UTol, theMinLen);
+        UTol, theMinLen,
+        ACompOldBehavior);
 }
 
 
@@ -105,7 +108,8 @@ void GCPnts_TangentialDeflection::Initialize (
  const Standard_Real    CurvatureDeflection,
  const Standard_Integer MinimumOfPoints,
  const Standard_Real    UTol,
- const Standard_Real    theMinLen)
+ const Standard_Real    theMinLen,
+ const Standard_Boolean ACompOldBehavior)
 
 {
   Initialize (C, 
@@ -114,7 +118,8 @@ void GCPnts_TangentialDeflection::Initialize (
               AngularDeflection, 
               CurvatureDeflection,
               MinimumOfPoints,
-              UTol, theMinLen);
+              UTol, theMinLen,
+              ACompOldBehavior);
 }
 
 
@@ -131,12 +136,14 @@ void GCPnts_TangentialDeflection::Initialize (
  const Standard_Real    CurvatureDeflection,
  const Standard_Integer MinimumOfPoints,
  const Standard_Real    UTol,
- const Standard_Real    theMinLen)
+ const Standard_Real    theMinLen,
+ const Standard_Boolean ACompOldBehavior)
 
 {
   
   Standard_ConstructionError_Raise_if (CurvatureDeflection <= Precision::Confusion () || AngularDeflection   <= Precision::Angular (), "GCPnts_TangentialDeflection::Initialize - Zero Deflection")
 
+ aCompOldBehavior = ACompOldBehavior;
  parameters.Clear ();
  points    .Clear ();
  if (FirstParameter < LastParameter) {
@@ -195,9 +202,9 @@ void GCPnts_TangentialDeflection::PerformLinear (const TheCurve& C) {
   parameters.Append (firstu);
   points    .Append (P);
   if (minNbPnts > 2) {
-    Standard_Real Du = (lastu - firstu) / minNbPnts;
+    Standard_Real Du = (lastu - firstu) / (minNbPnts - 1);
     Standard_Real U = firstu + Du;
-    for (Standard_Integer i = 2; i <= minNbPnts; i++) {
+    for (Standard_Integer i = 2; i < minNbPnts; i++) {
       D0 (C, U, P);
       parameters.Append (U);
       points    .Append (P);
@@ -287,18 +294,19 @@ void GCPnts_TangentialDeflection::PerformCurve (const TheCurve& C)
     {
       //Si c'est une droite on verifie en calculant minNbPoints :
       Standard_Boolean IsLine   = Standard_True;
+      Standard_Boolean IsSequential = Standard_True;
       Standard_Integer NbPoints = (minNbPnts > 3) ? minNbPnts : 3;
       switch (C.GetType()) {
       case GeomAbs_BSplineCurve:
         {
           Handle_TheBSplineCurve BS = C.BSpline() ;
-          NbPoints = Max(BS->Degree() + 1, NbPoints);
+          NbPoints = Max(BS->NbPoles(), Max(BS->Degree() + 1, NbPoints));
           break;
         }
       case GeomAbs_BezierCurve:
         {
           Handle_TheBezierCurve  BZ = C.Bezier();
-          NbPoints = Max(BZ->Degree() + 1, NbPoints);
+          NbPoints = Max(BZ->NbPoles(), Max(BZ->Degree() + 1, NbPoints));
           break;
         }
       default:
@@ -308,8 +316,8 @@ void GCPnts_TangentialDeflection::PerformCurve (const TheCurve& C)
       for (i = 1; i <= NbInterv && IsLine; ++i)
       {
         // Avoid usage intervals out of [firstu, lastu].
-        if ((Intervs(i+1) < firstu) ||
-            (Intervs(i)   > lastu))
+        if ((Intervs(i+1) <= firstu) ||
+            (Intervs(i)   >= lastu))
         {
           continue;
         }
@@ -325,8 +333,8 @@ void GCPnts_TangentialDeflection::PerformCurve (const TheCurve& C)
           Intervs(i + 1) = lastu;
         }
 
-        Standard_Real delta = (Intervs(i+1) - Intervs(i))/NbPoints;
-        for (j = 1; j <= NbPoints && IsLine; ++j)
+        Standard_Real delta = (Intervs(i+1) - Intervs(i))/(NbPoints-1);
+        for (j = 1; j < NbPoints && IsLine; ++j)
         {
           param = Intervs(i) + j*delta;
           D0 (C, param, MiddlePoint);
@@ -336,6 +344,13 @@ void GCPnts_TangentialDeflection::PerformCurve (const TheCurve& C)
           {
             const Standard_Real aAngle = V2.CrossMagnitude(V1)/(L1*L2);
             IsLine = (aAngle < ATol);
+
+            // Check if points on line are subsequent
+            if(IsLine && IsSequential)
+            {
+                gp_XYZ V3 = LastPoint.XYZ() - MiddlePoint.XYZ();
+                IsSequential = (V3.Dot(V2) >= 0.0);
+            }
           }
         }
       }
@@ -345,7 +360,18 @@ void GCPnts_TangentialDeflection::PerformCurve (const TheCurve& C)
         parameters.Clear();
         points    .Clear();
 
+        const Standard_Integer oldMinNbPoints = minNbPnts;
+        if(!IsSequential)
+        {
+            minNbPnts = NbPoints;
+        }
+
         PerformLinear(C);
+
+        if(!IsSequential)
+        {
+            minNbPnts = oldMinNbPoints;
+        }
         return;
       }
       else
@@ -389,6 +415,7 @@ void GCPnts_TangentialDeflection::PerformCurve (const TheCurve& C)
   Standard_Boolean MorePoints = Standard_True;
   Standard_Real U2            = firstu;   
   Standard_Real AngleMax      = angularDeflection * 0.5;  //car on prend le point milieu
+  Standard_Real MinLen2       = myMinLen * myMinLen;
   Standard_Integer aIdx[2] = {Intervs.Lower(), Intervs.Lower()}; // Indexes of intervals of U1 and U2, used to handle non-uniform case.
   Standard_Boolean isNeedToCheck = Standard_False;
   gp_Pnt aPrevPoint = points.Last();
@@ -432,17 +459,17 @@ void GCPnts_TangentialDeflection::PerformCurve (const TheCurve& C)
 
       V1 = (CurrentPoint.XYZ() - aPrevPoint.XYZ()); //Critere de fleche
       V2 = (MiddlePoint.XYZ()  - aPrevPoint.XYZ());
-      L1 = V1.Modulus ();
+      L1 = V1.SquareModulus ();
 
-      FCoef = (L1 > myMinLen) ? 
-        V1.CrossMagnitude(V2)/(L1*curvatureDeflection) : 0.0;
+      FCoef = (L1 > MinLen2) ?
+        V1.CrossMagnitude(V2)/(Sqrt(L1)*curvatureDeflection) : 0.0;
 
       V1 = (CurrentPoint.XYZ() - MiddlePoint.XYZ()); //Critere d'angle
-      L1 = V1.Modulus ();
-      L2 = V2.Modulus ();
-      if (L1 > myMinLen && L2 > myMinLen)
+      L1 = V1.SquareModulus ();
+      L2 = V2.SquareModulus ();
+      if (L1 > MinLen2 && L2 > MinLen2)
       {
-        Standard_Real angg = V1.CrossMagnitude(V2) / (L1 * L2);
+        Standard_Real angg = V1.CrossMagnitude(V2) / Sqrt(L1 * L2);
         ACoef = angg / AngleMax;
       }
       else
@@ -585,8 +612,10 @@ void GCPnts_TangentialDeflection::PerformCurve (const TheCurve& C)
     }
   }
   //Additional check for intervals
-  Standard_Real MinLen2 = myMinLen * myMinLen;
   Standard_Integer MaxNbp = 10 * Nbp;
+
+  const Standard_Real AngleMaxFixed = aCompOldBehavior ? AngleMax : Sqrt(1.0 - AngleMax * AngleMax);
+
   for(i = 1; i < Nbp; ++i)
   {
     U1 = parameters(i);
@@ -594,14 +623,16 @@ void GCPnts_TangentialDeflection::PerformCurve (const TheCurve& C)
     // Check maximal deflection on interval;
     Standard_Real dmax = 0.;
     Standard_Real umax = 0.;
-    Standard_Real amax = 0.;
     EstimDefl(C, U1, U2, dmax, umax);
     const gp_Pnt& P1 = points(i);
     const gp_Pnt& P2 = points(i+1);
     D0(C, umax, MiddlePoint);
-    amax = EstimAngl(P1, MiddlePoint, P2);
-    if(dmax > curvatureDeflection || amax > AngleMax)
+
+    Standard_Real amax = aCompOldBehavior ? EstimAnglOld(P1, MiddlePoint, P2) : EstimAngl(P1, MiddlePoint, P2);
+
+    if(dmax > curvatureDeflection || (aCompOldBehavior ? amax - AngleMaxFixed : AngleMaxFixed - amax) > ATol)
     {
+      
       if(umax - U1 > uTol && U2 - umax > uTol)
       {
         if (P1.SquareDistance(MiddlePoint) > MinLen2 && P2.SquareDistance(MiddlePoint) > MinLen2)
@@ -638,7 +669,7 @@ void GCPnts_TangentialDeflection::EstimDefl (const TheCurve& C,
   Standard_Real reltol = Max(1.e-3, 2.*uTol/((Abs(U1) + Abs(U2))));
   //
   math_BrentMinimum anOptLoc(reltol, aNbIter, uTol);
-  anOptLoc.Perform(aFunc, U1, (U1+U2)/2., U2);
+  anOptLoc.Perform(aFunc, U1, (U1+U2)*0.5, U2);
   if(anOptLoc.IsDone())
   {
     MaxDefl = Sqrt(-anOptLoc.Minimum());

src/GeometryTest/GeometryTest_CurveCommands.cxx

@@ -1032,7 +1032,7 @@ static Standard_Integer crvtpoints (Draw_Interpretor& di, Standard_Integer n, co
   defl = Draw::Atof(a[3]);
 
   if(n > 3)
-    angle = Draw::Atof(a[4]);
+    angle = Draw::Atof(a[4]) * M_PI / 180;
 
   GCPnts_TangentialDeflection PntGen(aHCurve->Curve(), angle, defl, 2);
   

src/IVtkOCC/IVtkOCC_ShapeMesher.cxx

@@ -128,7 +128,8 @@ void IVtkOCC_ShapeMesher::meshShape()
     Handle(BRepMesh_DiscretRoot) anAlgo;
     anAlgo = BRepMesh_DiscretFactory::Get().Discret (anOcctShape,
                                                      aDeflection,
-                                                     GetDeviationAngle());
+                                                     GetDeviationAngle(),
+                                                     GetTDOldBehavior());
     if (!anAlgo.IsNull())
     {
       anAlgo->Perform();
@@ -455,12 +456,13 @@ static void FindLimits (const Adaptor3d_Curve& theCurve,
 //! @param [in] theU2 maximal curve parameter value
 //! @param [out] thePoints the container for generated polyline
 //================================================================
-static void DrawCurve (Adaptor3d_Curve&    theCurve,
-                       const Standard_Real theDeflection,
-                       const Standard_Real theAngle,
-                       const Standard_Real theU1,
-                       const Standard_Real theU2,
-                       IVtk_Polyline&      thePoints)
+static void DrawCurve (Adaptor3d_Curve&       theCurve,
+                       const Standard_Real    theDeflection,
+                       const Standard_Real    theAngle,
+                       const Standard_Boolean theTDOldBehavior,
+                       const Standard_Real    theU1,
+                       const Standard_Real    theU2,
+                       IVtk_Polyline&         thePoints)
 {
   switch (theCurve.GetType())
   {
@@ -493,7 +495,7 @@ static void DrawCurve (Adaptor3d_Curve&    theCurve,
           anU1 = Max(anU1, anU1);
           anU2 = Min(anU2, anU2);
 
-          GCPnts_TangentialDeflection anAlgo (theCurve, anU1, anU2, theAngle, theDeflection);
+          GCPnts_TangentialDeflection anAlgo (theCurve, anU1, anU2, theAngle, theDeflection, theTDOldBehavior);
           NumberOfPoints = anAlgo.NbPoints();
 
           if (NumberOfPoints > 0)
@@ -766,7 +768,7 @@ void IVtkOCC_ShapeMesher::buildIsoLines (const Handle(BRepAdaptor_HSurface)& the
         if (aB2 - aB1 > Precision::Confusion())
         {
           IVtk_Polyline aPoints;
-          DrawCurve (aGeomCurve, aDeflection, anAngle, aB1, aB2, aPoints);
+          DrawCurve (aGeomCurve, aDeflection, anAngle, GetTDOldBehavior(), aB1, aB2, aPoints);
           thePolylines.Append (aPoints);
         }
       }
@@ -784,7 +786,7 @@ void IVtkOCC_ShapeMesher::buildIsoLines (const Handle(BRepAdaptor_HSurface)& the
         if (aB2 - aB1>Precision::Confusion())
         {
           IVtk_Polyline aPoints;
-          DrawCurve (anIso, aDeflection, anAngle, aB1, aB2, aPoints);
+          DrawCurve (anIso, aDeflection, anAngle, GetTDOldBehavior(), aB1, aB2, aPoints);
           thePolylines.Append (aPoints);
         }
       }

src/IVtkOCC/IVtkOCC_ShapeMesher.hxx

@@ -50,9 +50,11 @@ public:
   IVtkOCC_ShapeMesher (const Standard_Real& theDevCoeff = 0.0001,
                        const Standard_Real& theDevAngle = 12.0 * M_PI / 180.0,
                        const Standard_Integer theNbUIsos = 1,
-                       const Standard_Integer theNbVIsos = 1)
+                       const Standard_Integer theNbVIsos = 1,
+                       const Standard_Boolean theTDOldBehavior = Standard_True)
  : myDevCoeff (theDevCoeff),
    myDevAngle (theDevAngle),
+   myTDOldBehavior(theTDOldBehavior),
    myDeflection (0.0)
   {
     myNbIsos[0] = theNbUIsos;
@@ -85,6 +87,13 @@ public:
     return myDevAngle;
   }
 
+  //! Returns tangential deflection behavior used in the algorithm
+  //! @return tangential deflection behavior
+  Standard_Boolean GetTDOldBehavior() const
+  {
+      return myTDOldBehavior;
+  }
+
 protected:
   //! Executes the mesh generation algorithms. To be defined in implementation class.
   Standard_EXPORT virtual void internalBuild() Standard_OVERRIDE;
@@ -186,6 +195,7 @@ private:
   Standard_Real         myDevAngle;
   mutable Standard_Real myDeflection;
   Standard_Integer      myNbIsos[2];
+  Standard_Boolean      myTDOldBehavior;
 };
 
 #endif //  __IVTKOCC_SHAPEMESHER_H__

tests/bugs/modalg_7/bug30020

@@ -0,0 +1,19 @@
+puts "========"
+puts "0030020: Incorrect bspline visualization"
+puts "========\n"
+
+set F [open $imagedir/pnts w]
+puts $F "3 3d"
+puts $F "0 0 0"
+puts $F "2 0 0"
+puts $F "1 0 0"
+close $F
+interpol c $imagedir/pnts
+file delete $imagedir/pnts
+
+set out [crvtpoints r c 0.1 1]
+if {[lindex $out 3] != 3} {
+  puts "Error: number of points is not equal to 3"
+}
+
+checklength r -l 3

tests/bugs/moddata_3/bug25489

@@ -12,7 +12,7 @@ subshape a e 8
 mkcurve c a_8
 
 set deflection 0.001
-set info [crvtpoints r c ${deflection} pi/6]
+set info [crvtpoints r c ${deflection} 30]
 
 set str1 "Nb points +: +(\[-0-9.+eE\]+)\n"
 set str2 "Max defl: +(\[-0-9.+eE\]+) +(\[-0-9.+eE\]+) +(\[-0-9.+eE\]+) +(\[-0-9.+eE\]+)"

tests/bugs/moddata_3/bug25737_2

@@ -16,7 +16,7 @@ donly a_1
 fit
 
 set deflection 1.
-set angular_deflection 0.349
+set angular_deflection 20
 set info [crvtpoints r c ${deflection} ${angular_deflection}]
 
 set str1 "Nb points +: +(\[-0-9.+eE\]+)\n"

tests/bugs/moddata_3/bug27108

@@ -12,7 +12,7 @@ restore [locate_data_file bug27108_Left.brep] a
 
 explode a e
 mkcurve c a_1
-set bug_info [crvtpoints result c $bug27108_requested_deflection 20*pi/180]
+set bug_info [crvtpoints result c $bug27108_requested_deflection 20]
 
 smallview
 donly c result