0026736: Errors in BRepOffsetAPI_MakeOffset: overlapping arcs are processed incorrect in mode GeomAbs_Intersection

Test cases for issue CR26736

src/BRepFill/BRepFill_OffsetWire.cxx

@@ -938,7 +938,8 @@ void BRepFill_OffsetWire::PerformWithBiLo
     // Construction of vertices on edges parallel to the spine.
     //-----------------------------------------------------------
 
-    Trim.IntersectWith(E [0], E [1], myJoinType, Params);
+    Trim.IntersectWith(E[0], E[1], S[0], S[1], Ends[0], Ends[1],
+                       myJoinType, myIsOpenResult, Params);
 
     for (Standard_Integer s = 1; s <= Params.Length(); s++) {
       TopoDS_Vertex VC;
@@ -1291,10 +1292,22 @@ void BRepFill_OffsetWire::UpdateDetromp (BRepFill_DataMapOfOrientedShapeListOfSh
                                          const BRepFill_TrimEdgeTool&    Trim) const
 {
   Standard_Integer ii = 1;
+
+  if (myJoinType == GeomAbs_Intersection)
+  {
+    for (; ii <= Vertices.Length(); ii++)
+    {
+      const TopoDS_Vertex& aVertex = TopoDS::Vertex(Vertices.Value(ii));
+      Detromp(Shape1).Append(aVertex);
+      Detromp(Shape2).Append(aVertex);
+    }
+  }
+  else //myJoinType == GeomAbs_Arc
+  {
     Standard_Real    U1,U2;
     TopoDS_Vertex    V1,V2;
     
-  Handle(Geom2d_Curve) Bis (Bisec.Value());
+    const Handle(Geom2d_Curve)& Bis = Bisec.Value();
     
     U1 = Bis->FirstParameter();
     
@@ -1309,10 +1322,7 @@ void BRepFill_OffsetWire::UpdateDetromp (BRepFill_DataMapOfOrientedShapeListOfSh
       V2 = TopoDS::Vertex(Vertices.Value(ii));
       
       gp_Pnt2d P = Bis->Value((U2 + U1)*0.5);
-    Standard_Boolean IsP_inside = Standard_True;
+      if (!Trim.IsInside(P)) {
-    if ((myJoinType != GeomAbs_Intersection) || EOnE)
-      IsP_inside = Trim.IsInside(P);
-    if (!IsP_inside) {
         if (!V1.IsNull()) {
           Detromp(Shape1).Append(V1);
           Detromp(Shape2).Append(V1);
@@ -1330,10 +1340,7 @@ void BRepFill_OffsetWire::UpdateDetromp (BRepFill_DataMapOfOrientedShapeListOfSh
     if (!EOnE) {
       if (!Precision::IsInfinite(U2)) {
         gp_Pnt2d P = Bis->Value((U2 + U1)*0.5);
-      Standard_Boolean IsP_inside = Standard_False;
+        if (!Trim.IsInside(P)) {
-      if (myJoinType == GeomAbs_Arc)
-        IsP_inside = Trim.IsInside(P);
-      if (!IsP_inside) {
           if (!V1.IsNull()) {
             Detromp(Shape1).Append(V1);
             Detromp(Shape2).Append(V1);
@@ -1354,6 +1361,7 @@ void BRepFill_OffsetWire::UpdateDetromp (BRepFill_DataMapOfOrientedShapeListOfSh
     //    Detromp(Shape2).Append(V1);
     //  }
     //}
+  } //end of else (myJoinType==GeomAbs_Arc)
 }
 
 //=======================================================================

src/BRepFill/BRepFill_TrimEdgeTool.cxx

@@ -38,6 +38,9 @@
 #include <TopLoc_Location.hxx>
 #include <TopoDS.hxx>
 #include <TopoDS_Edge.hxx>
+#include <TopoDS_Vertex.hxx>
+#include <TopExp.hxx>
+#include <BRepAdaptor_Curve.hxx>
 
 #ifdef OCCT_DEBUG
 //#define DRAW
@@ -311,7 +314,12 @@ static void EvalParametersBis(const Geom2dAdaptor_Curve& Bis,
 
 void BRepFill_TrimEdgeTool::IntersectWith(const TopoDS_Edge& Edge1,
                                           const TopoDS_Edge& Edge2,
+                                          const TopoDS_Shape& InitShape1,
+                                          const TopoDS_Shape& InitShape2,
+                                          const TopoDS_Vertex& End1,
+                                          const TopoDS_Vertex& End2,
                                           const GeomAbs_JoinType theJoinType,
+                                          const Standard_Boolean IsOpenResult,
                                           TColgp_SequenceOfPnt& Params)
 {
   Params.Clear();
@@ -563,19 +571,75 @@ void BRepFill_TrimEdgeTool::IntersectWith(const TopoDS_Edge& Edge1,
 
   NbPoints = Params.Length();
 
-  if (NbPoints > 0 && theJoinType == GeomAbs_Intersection)
+  //Now we define: if there are more than one point of intersection
+  //is it Ok ?
+  Standard_Real init_fpar = RealFirst(), init_lpar = RealLast();
+  if (NbPoints > 1 &&
+      theJoinType == GeomAbs_Intersection &&
+      InitShape1.ShapeType() != TopAbs_VERTEX &&
+      InitShape2.ShapeType() != TopAbs_VERTEX)
+  {
+    //definition of initial first and last parameters:
+    //this is inverse procedure to extension of parameters
+    //(see BRepFill_OffsetWire, function MakeOffset, case of Circle)
+    const TopoDS_Edge& InitEdge1 = TopoDS::Edge(InitShape1);
+    Standard_Boolean ToExtendFirstPar = Standard_True;
+    Standard_Boolean ToExtendLastPar  = Standard_True;
+    if (IsOpenResult)
+    {
+      TopoDS_Vertex V1, V2;
+      TopExp::Vertices(InitEdge1, V1, V2);
+      if (V1.IsSame(End1) ||
+          V1.IsSame(End2))
+        ToExtendFirstPar = Standard_False;
+      if (V2.IsSame(End1) ||
+          V2.IsSame(End2))
+        ToExtendLastPar  = Standard_False;
+    }
+    BRepAdaptor_Curve IC1(InitEdge1);
+    if (IC1.GetType() == GeomAbs_Circle)
+    {
+      Standard_Real Delta = 2*M_PI - IC1.LastParameter() + IC1.FirstParameter();
+      if (ToExtendFirstPar && ToExtendLastPar)
+        init_fpar = AC1.FirstParameter() + Delta/2;
+      else if (ToExtendFirstPar)
+        init_fpar = AC1.FirstParameter() + Delta;
+      else if (ToExtendLastPar)
+        init_fpar = AC1.FirstParameter();
+      init_lpar = init_fpar + IC1.LastParameter() - IC1.FirstParameter();
+    }
+  }
+  
+  
+  if (NbPoints > 1 && theJoinType == GeomAbs_Intersection)
   {
     //Remove all vertices with non-minimal parameter
+    //if they are out of initial range
     Standard_Integer imin = 1;
     for (i = 2; i <= NbPoints; i++)
       if (Params(i).X() < Params(imin).X())
         imin = i;
+
+    TColgp_SequenceOfPnt ParamsCopy = Params;
+    TColgp_SequenceOfPnt Points2Copy = Points2;
+    Params.Clear();
+    Points2.Clear();
+    for (i = 1; i <= ParamsCopy.Length(); i++)
+      if (imin == i ||
+          (ParamsCopy(i).Y() >= init_fpar && ParamsCopy(i).Y() <= init_lpar))
+      {
+        Params.Append(ParamsCopy(i));
+        Points2.Append(Points2Copy(i));
+      }
+
+    /*
     gp_Pnt Pnt1 = Params(imin);
     gp_Pnt Pnt2 = Points2(imin);
     Params.Clear();
     Points2.Clear();
     Params.Append(Pnt1);
     Points2.Append(Pnt2);
+    */
   }
   
   NbPoints = Params.Length();

src/BRepFill/BRepFill_TrimEdgeTool.hxx

@@ -32,6 +32,8 @@ class Geom2d_Curve;
 class Bisector_Bisec;
 class Geom2d_Geometry;
 class TopoDS_Edge;
+class TopoDS_Shape;
+class TopoDS_Vertex;
 class gp_Pnt2d;
 
 
@@ -47,7 +49,7 @@ public:
   
   Standard_EXPORT BRepFill_TrimEdgeTool(const Bisector_Bisec& Bisec, const Handle(Geom2d_Geometry)& S1, const Handle(Geom2d_Geometry)& S2, const Standard_Real Offset);
   
-  Standard_EXPORT void IntersectWith (const TopoDS_Edge& Edge1, const TopoDS_Edge& Edge2, const GeomAbs_JoinType theJoinType, TColgp_SequenceOfPnt& Params);
+  Standard_EXPORT   void IntersectWith (const TopoDS_Edge& Edge1, const TopoDS_Edge& Edge2, const TopoDS_Shape& InitShape1, const TopoDS_Shape& InitShape2, const TopoDS_Vertex& End1, const TopoDS_Vertex& End2, const GeomAbs_JoinType theJoinType, const Standard_Boolean IsOpenResult, TColgp_SequenceOfPnt& Params) ;
   
   Standard_EXPORT void AddOrConfuse (const Standard_Boolean Start, const TopoDS_Edge& Edge1, const TopoDS_Edge& Edge2, TColgp_SequenceOfPnt& Params) const;
   

tests/bugs/modalg_6/bug26736_1

@@ -0,0 +1,18 @@
+puts "============"
+puts "OCC26736"
+puts "============"
+puts ""
+##################################
+# Errors in BRepOffsetAPI_MakeOffset: overlapping arcs are processed incorrect in mode GeomAbs_Intersection
+##################################
+
+smallview
+
+restore [locate_data_file bug26736_arc1.brep] a
+wire ww a
+donly ww
+fit
+mkoffset result ww 10 8 i
+fit
+
+set only_screen_axo 1

tests/bugs/modalg_6/bug26736_2

@@ -0,0 +1,26 @@
+puts "============"
+puts "OCC26736"
+puts "============"
+puts ""
+##################################
+# Errors in BRepOffsetAPI_MakeOffset: overlapping arcs are processed incorrect in mode GeomAbs_Intersection
+##################################
+
+circle c1 7 0 0 5
+circle c2 -7 0 0 0 0 1 0 1 0 5
+trim c1 c1 pi/2 3*pi/2
+trim c2 c2 pi 2*pi
+mkedge e1 c1
+mkedge e2 c2
+polyline pp1 -7 5 0 -7 30 0 7 30 0 7 5 0
+polyline pp2 7 -5 0 7 -30 0 -7 -30 0 -7 -5 0
+wire ww pp1 e1 pp2 e2
+
+smallview
+donly ww
+fit
+
+mkoffset result ww 1 -3. i
+fit
+
+set only_screen_axo 1