0032833: Shape Healing - FixShape needs to be improved

Additional check before adding degenerated edge

src/ShapeAnalysis/ShapeAnalysis_Wire.cxx

@@ -1504,7 +1504,8 @@ Standard_Boolean ShapeAnalysis_Wire::CheckIntersectingEdges (const Standard_Inte
 
 Standard_Boolean ShapeAnalysis_Wire::CheckLacking (const Standard_Integer num,
 						   const Standard_Real Tolerance,
-						   gp_Pnt2d &p2d1, gp_Pnt2d &p2d2) 
+						   gp_Pnt2d &p2d1, gp_Pnt2d &p2d2,
+                                                   gp_Vec2d& theTangent1, gp_Vec2d& theTangent2)
 {
   myStatus = ShapeExtend::EncodeStatus (ShapeExtend_OK);
   if ( ! IsReady() ) return Standard_False;
@@ -1529,22 +1530,24 @@ Standard_Boolean ShapeAnalysis_Wire::CheckLacking (const Standard_Integer num,
   }
 
   Standard_Real a, b;
-  gp_Vec2d v1, v2, v12;
+  gp_Vec2d /*v1, v2,*/ v12;
   Handle(Geom2d_Curve) c2d;
   if ( ! sae.PCurve ( E1, myFace, c2d, a, b, Standard_True ) ) {
     myStatus |= ShapeExtend::EncodeStatus (ShapeExtend_FAIL3);
     return Standard_False;
   }
   Geom2dAdaptor_Curve anAdapt(c2d);
-  anAdapt.D1(b, p2d1, v1);
-  if ( E1.Orientation() == TopAbs_REVERSED ) v1.Reverse();
+  anAdapt.D1(b, p2d1, theTangent1);
+  if ( E1.Orientation() == TopAbs_REVERSED )
+    theTangent1.Reverse();
   if ( ! sae.PCurve ( E2, myFace, c2d, a, b, Standard_True ) ) {
     myStatus |= ShapeExtend::EncodeStatus (ShapeExtend_FAIL3);
     return Standard_False;
   }
   anAdapt.Load(c2d);
-  anAdapt.D1(a, p2d2, v2);
-  if ( E2.Orientation() == TopAbs_REVERSED ) v2.Reverse();
+  anAdapt.D1(a, p2d2, theTangent2);
+  if ( E2.Orientation() == TopAbs_REVERSED )
+    theTangent2.Reverse();
   v12 = p2d2.XY() - p2d1.XY();
   myMax2d = v12.SquareMagnitude();
 
@@ -1561,8 +1564,8 @@ Standard_Boolean ShapeAnalysis_Wire::CheckLacking (const Standard_Integer num,
   myStatus |= ShapeExtend::EncodeStatus ( ShapeExtend_DONE1 );
 
   if ( myMax2d < Precision::PConfusion() || //:abv 03.06.02 CTS21866.stp
-       ( v1.SquareMagnitude() > gp::Resolution() && Abs ( v12.Angle ( v1 ) ) > 0.9 * M_PI ) ||
-       ( v2.SquareMagnitude() > gp::Resolution() && Abs ( v12.Angle ( v2 ) ) > 0.9 * M_PI ) ) 
+       ( theTangent1.SquareMagnitude() > gp::Resolution() && Abs ( v12.Angle ( theTangent1 ) ) > 0.9 * M_PI ) ||
+       ( theTangent2.SquareMagnitude() > gp::Resolution() && Abs ( v12.Angle ( theTangent2 ) ) > 0.9 * M_PI ) ) 
        myStatus |= ShapeExtend::EncodeStatus ( ShapeExtend_DONE2 );
   return Standard_True;
 }
@@ -1577,7 +1580,8 @@ Standard_Boolean ShapeAnalysis_Wire::CheckLacking (const Standard_Integer num,
 						   const Standard_Real Tolerance)
 {
   gp_Pnt2d p1, p2;
-  return CheckLacking (num, Tolerance, p1, p2);
+  gp_Vec2d aTangent1, aTangent2;
+  return CheckLacking (num, Tolerance, p1, p2, aTangent1, aTangent2);
 }
 
 //=======================================================================

src/ShapeAnalysis/ShapeAnalysis_Wire.hxx

@@ -403,7 +403,10 @@ public:
   //! DONE2: is set (together with DONE1) if gap is detected and the
   //! vector (p2d2 - p2d1) goes in direction opposite to the pcurves
   //! of the edges (if angle is more than 0.9*PI).
-  Standard_EXPORT Standard_Boolean CheckLacking (const Standard_Integer num, const Standard_Real Tolerance, gp_Pnt2d& p2d1, gp_Pnt2d& p2d2);
+  Standard_EXPORT Standard_Boolean CheckLacking (const Standard_Integer num,
+                                                 const Standard_Real Tolerance,
+                                                 gp_Pnt2d& p2d1, gp_Pnt2d& p2d2,
+                                                 gp_Vec2d& theTangent1, gp_Vec2d& theTangent2);
   
   //! Checks if there is a gap in 2D between edges and not comprised by vertex tolerance
   //! The value of SBWD.thepreci is used.

src/ShapeFix/ShapeFix_Wire.cxx

@@ -2930,7 +2930,8 @@ Standard_Boolean ShapeFix_Wire::FixLacking (const Standard_Integer num,
   //=============
   // First phase: analysis whether the problem (gap) exists
   gp_Pnt2d p2d1, p2d2;
-  myAnalyzer->CheckLacking ( num, ( force ? Precision() : 0. ), p2d1, p2d2 );
+  gp_Vec2d aTangent1, aTangent2;
+  myAnalyzer->CheckLacking (num, ( force ? Precision() : 0. ), p2d1, p2d2, aTangent1, aTangent2);
   if ( myAnalyzer->LastCheckStatus ( ShapeExtend_FAIL ) ) {
     myLastFixStatus |= ShapeExtend::EncodeStatus ( ShapeExtend_FAIL1 );
   }
@@ -3052,8 +3053,28 @@ Standard_Boolean ShapeFix_Wire::FixLacking (const Standard_Integer num,
       gp_Pnt pV = 0.5 * ( BRep_Tool::Pnt(V1).XYZ() + BRep_Tool::Pnt(V2).XYZ() );
       gp_Pnt pm = myAnalyzer->Surface()->Value ( 0.5 * ( p2d1.XY() + p2d2.XY() ) );
 
+      //Additional check
+      //const Standard_Real anAngularTol = 1.e-5;
+      const Standard_Real aMaxAngle = 7*M_PI/8;
+      Standard_Boolean anIsGoodConnection = Standard_True;
+      gp_Vec2d aVecP1P2 (p2d1, p2d2);
+      if (aVecP1P2.SquareMagnitude() > Precision::SquareConfusion() &&
+          aTangent1.SquareMagnitude() > Precision::SquareConfusion() &&
+          aTangent2.SquareMagnitude() > Precision::SquareConfusion())
+      {
+        Standard_Real anAngle1 = aTangent1.Angle (aVecP1P2);
+        Standard_Real anAngle2 = aVecP1P2.Angle (aTangent2);
+        if (Abs(anAngle1) > aMaxAngle ||
+            Abs(anAngle2) > aMaxAngle)
+          anIsGoodConnection = Standard_False;
+      }
+
       Standard_Real dist = pV.Distance ( pm );
-      if ( dist <= tol ) doAddDegen = Standard_True;
+      if ( dist <= tol )
+      {
+        if (anIsGoodConnection)
+          doAddDegen = Standard_True;
+      }
       else if ( myTopoMode ) doAddClosed = Standard_True;
       else if ( dist <= MaxTolerance() ) { //:r7 abv 12 Apr 99: t3d_opt.stp #14245 after S4136
 	doAddDegen = Standard_True;