0024964: ThruSections crashes the DRAW.exe
[occt.git] / src / BRepOffsetAPI / BRepOffsetAPI_ThruSections.cxx
index 3f79ed9..29e3711 100644 (file)
 //=======================================================================
 
 static Standard_Real PreciseUpar(const Standard_Real anUpar,
-                                 const Handle(Geom_BSplineSurface)& aSurface)
+  const Handle(Geom_BSplineSurface)& aSurface)
 {
   Standard_Real Tol = Precision::PConfusion();
   Standard_Integer i1, i2;
@@ -126,17 +126,17 @@ static Standard_Real PreciseUpar(const Standard_Real anUpar,
 //=======================================================================
 
 static Standard_Boolean PerformPlan(const TopoDS_Wire& W,
-                                   const Standard_Real presPln,
-                                   TopoDS_Face& theFace)
+  const Standard_Real presPln,
+  TopoDS_Face& theFace)
 {
   Standard_Boolean isDegen = Standard_True;
   TopoDS_Iterator iter(W);
   for (; iter.More(); iter.Next())
-    {
-      const TopoDS_Edge& anEdge = TopoDS::Edge(iter.Value());
-      if (!BRep_Tool::Degenerated(anEdge))
-       isDegen = Standard_False;
-    }
+  {
+    const TopoDS_Edge& anEdge = TopoDS::Edge(iter.Value());
+    if (!BRep_Tool::Degenerated(anEdge))
+      isDegen = Standard_False;
+  }
   if (isDegen)
     return Standard_True;
 
@@ -144,22 +144,22 @@ static Standard_Boolean PerformPlan(const TopoDS_Wire& W,
   if (!W.IsNull()) {
     BRepBuilderAPI_FindPlane Searcher( W, presPln );
     if (Searcher.Found())
-      {
-       theFace = BRepBuilderAPI_MakeFace(Searcher.Plane(), W);
-       Ok = Standard_True;
-      }
+    {
+      theFace = BRepBuilderAPI_MakeFace(Searcher.Plane(), W);
+      Ok = Standard_True;
+    }
     else // try to find another surface
+    {
+      BRepBuilderAPI_MakeFace MF( W );
+      if (MF.IsDone())
       {
-       BRepBuilderAPI_MakeFace MF( W );
-       if (MF.IsDone())
-         {
-           theFace = MF.Face();
-           Ok = Standard_True;
-         }
+        theFace = MF.Face();
+        Ok = Standard_True;
       }
+    }
   }
 
- return Ok;
+  return Ok;
 }
 
 //=============================================================================
@@ -168,7 +168,7 @@ static Standard_Boolean PerformPlan(const TopoDS_Wire& W,
 //=============================================================================
 
 static Standard_Boolean IsSameOriented(const TopoDS_Shape& aFace,
-                                      const TopoDS_Shape& aShell)
+  const TopoDS_Shape& aShell)
 {
   TopExp_Explorer Explo(aFace, TopAbs_EDGE);
   TopoDS_Shape anEdge = Explo.Current();
@@ -180,11 +180,11 @@ static Standard_Boolean IsSameOriented(const TopoDS_Shape& aFace,
   const TopoDS_Shape& AdjacentFace = EFmap.FindFromKey(anEdge).First();
   TopoDS_Shape theEdge;
   for (Explo.Init(AdjacentFace, TopAbs_EDGE); Explo.More(); Explo.Next())
-    {
-      theEdge = Explo.Current();
-      if (theEdge.IsSame(anEdge))
-       break;
-    }
+  {
+    theEdge = Explo.Current();
+    if (theEdge.IsSame(anEdge))
+      break;
+  }
 
   TopAbs_Orientation Or2 = theEdge.Orientation();
   if (Or1 == Or2)
@@ -198,8 +198,8 @@ static Standard_Boolean IsSameOriented(const TopoDS_Shape& aFace,
 //=======================================================================
 
 static TopoDS_Solid MakeSolid(TopoDS_Shell& shell, const TopoDS_Wire& wire1,
-                             const TopoDS_Wire& wire2, const Standard_Real presPln,
-                             TopoDS_Face& face1, TopoDS_Face& face2)
+  const TopoDS_Wire& wire2, const Standard_Real presPln,
+  TopoDS_Face& face1, TopoDS_Face& face2)
 {
   if (shell.IsNull())
     StdFail_NotDone::Raise("Thrusections is not build");
@@ -207,31 +207,31 @@ static TopoDS_Solid MakeSolid(TopoDS_Shell& shell, const TopoDS_Wire& wire1,
   BRep_Builder BB;
 
   if (!B)
-    {
-      // It is necessary to close the extremities 
-      B =  PerformPlan(wire1, presPln, face1);
+  {
+    // It is necessary to close the extremities 
+    B =  PerformPlan(wire1, presPln, face1);
+    if (B) {
+      B =  PerformPlan(wire2, presPln, face2);
       if (B) {
-       B =  PerformPlan(wire2, presPln, face2);
-       if (B) {
-         if (!face1.IsNull() && !IsSameOriented( face1, shell ))
-           face1.Reverse();
-         if (!face2.IsNull() && !IsSameOriented( face2, shell ))
-           face2.Reverse();
-         
-         if (!face1.IsNull())
-           BB.Add(shell, face1);
-         if (!face2.IsNull())
-           BB.Add(shell, face2);
-         
-         shell.Closed(Standard_True);
-       }
+        if (!face1.IsNull() && !IsSameOriented( face1, shell ))
+          face1.Reverse();
+        if (!face2.IsNull() && !IsSameOriented( face2, shell ))
+          face2.Reverse();
+
+        if (!face1.IsNull())
+          BB.Add(shell, face1);
+        if (!face2.IsNull())
+          BB.Add(shell, face2);
+
+        shell.Closed(Standard_True);
       }
     }
+  }
 
   TopoDS_Solid solid;
   BB.MakeSolid(solid); 
   BB.Add(solid, shell);
-  
+
   // verify the orientation the solid
   BRepClass3d_SolidClassifier clas3d(solid);
   clas3d.PerformInfinitePoint(Precision::Confusion());
@@ -239,7 +239,7 @@ static TopoDS_Solid MakeSolid(TopoDS_Shell& shell, const TopoDS_Wire& wire1,
     BB.MakeSolid(solid); 
     TopoDS_Shape aLocalShape = shell.Reversed();
     BB.Add(solid, TopoDS::Shell(aLocalShape));
-//    B.Add(solid, TopoDS::Shell(newShell.Reversed()));
+    //    B.Add(solid, TopoDS::Shell(newShell.Reversed()));
   }
 
   solid.Closed(Standard_True);
@@ -253,11 +253,11 @@ static TopoDS_Solid MakeSolid(TopoDS_Shell& shell, const TopoDS_Wire& wire1,
 //=======================================================================
 
 BRepOffsetAPI_ThruSections::BRepOffsetAPI_ThruSections(const Standard_Boolean isSolid, const Standard_Boolean ruled,
-                                            const Standard_Real pres3d):
-                                            myIsSolid(isSolid), myIsRuled(ruled), myPres3d(pres3d)
+  const Standard_Real pres3d):
+myIsSolid(isSolid), myIsRuled(ruled), myPres3d(pres3d)
 {
   myWCheck = Standard_True;
-//----------------------------
+  //----------------------------
   myParamType = Approx_ChordLength; 
   myDegMax    = 8; 
   myContinuity = GeomAbs_C2;
@@ -274,13 +274,13 @@ BRepOffsetAPI_ThruSections::BRepOffsetAPI_ThruSections(const Standard_Boolean is
 //=======================================================================
 
 void BRepOffsetAPI_ThruSections::Init(const Standard_Boolean isSolid, const Standard_Boolean ruled,
-                                const Standard_Real pres3d)
+  const Standard_Real pres3d)
 {
   myIsSolid = isSolid;
   myIsRuled = ruled;
   myPres3d = pres3d;
   myWCheck = Standard_True;
-//----------------------------
+  //----------------------------
   myParamType = Approx_ChordLength; 
   myDegMax    = 6; 
   myContinuity = GeomAbs_C2;
@@ -348,39 +348,39 @@ void BRepOffsetAPI_ThruSections::Build()
   Standard_Integer i;
   TopExp_Explorer explo;
   for (i = 2; i <= myWires.Length()-1; i++)
+  {
+    Standard_Boolean wdeg = Standard_True;
+    for (explo.Init(myWires(i), TopAbs_EDGE); explo.More(); explo.Next())
     {
-      Standard_Boolean wdeg = Standard_True;
-      for (explo.Init(myWires(i), TopAbs_EDGE); explo.More(); explo.Next())
-       {
-         const TopoDS_Edge& anEdge = TopoDS::Edge(explo.Current());
-         wdeg = wdeg && (BRep_Tool::Degenerated(anEdge));
-       }
-      if (wdeg)
-       Standard_Failure::Raise("Wrong usage of punctual sections");
+      const TopoDS_Edge& anEdge = TopoDS::Edge(explo.Current());
+      wdeg = wdeg && (BRep_Tool::Degenerated(anEdge));
     }
+    if (wdeg)
+      Standard_Failure::Raise("Wrong usage of punctual sections");
+  }
   if (myWires.Length() <= 2)
-    {
-      Standard_Boolean wdeg = Standard_True;
-      for (i = 1; i <= myWires.Length(); i++)
-       for (explo.Init(myWires(i), TopAbs_EDGE); explo.More(); explo.Next())
-         {
-           const TopoDS_Edge& anEdge = TopoDS::Edge(explo.Current());
-           wdeg = wdeg && (BRep_Tool::Degenerated(anEdge));
-         }
+  {
+    Standard_Boolean wdeg = Standard_True;
+    for (i = 1; i <= myWires.Length(); i++)
+      for (explo.Init(myWires(i), TopAbs_EDGE); explo.More(); explo.Next())
+      {
+        const TopoDS_Edge& anEdge = TopoDS::Edge(explo.Current());
+        wdeg = wdeg && (BRep_Tool::Degenerated(anEdge));
+      }
       if (wdeg)
-       Standard_Failure::Raise("Wrong usage of punctual sections");
-    }
+        Standard_Failure::Raise("Wrong usage of punctual sections");
+  }
 
   if (myWCheck) {
     // compute origin and orientation on wires to avoid twisted results
     // and update wires to have same number of edges
-    
+
     // use BRepFill_CompatibleWires
     TopTools_SequenceOfShape WorkingSections;
     WorkingSections.Clear();
     TopTools_DataMapOfShapeListOfShape WorkingMap;
     WorkingMap.Clear();
-    
+
     // Calculate the working sections
     BRepFill_CompatibleWires Georges(myWires);
     Georges.Perform();
@@ -402,7 +402,7 @@ void BRepOffsetAPI_ThruSections::Build()
   }
   // Encode the Regularities
   BRepLib::EncodeRegularity(myShape);
-  
+
 }
 
 
@@ -415,7 +415,7 @@ void BRepOffsetAPI_ThruSections::CreateRuled()
 {
   Standard_Integer nbSects = myWires.Length();
   BRepFill_Generator aGene;
-//  for (Standard_Integer i=1; i<=nbSects; i++) {
+  //  for (Standard_Integer i=1; i<=nbSects; i++) {
   Standard_Integer i;
   for (i=1; i<=nbSects; i++) {
     aGene.AddWire(TopoDS::Wire(myWires(i)));
@@ -434,15 +434,15 @@ void BRepOffsetAPI_ThruSections::CreateRuled()
       BRep_Builder B;
       B.MakeSolid(solid); 
       B.Add(solid, shell);
-      
+
       // verify the orientation of the solid
       BRepClass3d_SolidClassifier clas3d(solid);
       clas3d.PerformInfinitePoint(Precision::Confusion());
       if (clas3d.State() == TopAbs_IN) {
-       B.MakeSolid(solid); 
-       TopoDS_Shape aLocalShape = shell.Reversed();
-       B.Add(solid, TopoDS::Shell(aLocalShape));
-//     B.Add(solid, TopoDS::Shell(shell.Reversed()));
+        B.MakeSolid(solid); 
+        TopoDS_Shape aLocalShape = shell.Reversed();
+        B.Add(solid, TopoDS::Shell(aLocalShape));
+        //     B.Add(solid, TopoDS::Shell(shell.Reversed()));
       }
       myShape = solid;
 
@@ -472,12 +472,12 @@ void BRepOffsetAPI_ThruSections::CreateRuled()
 
   TopTools_IndexedDataMapOfShapeListOfShape MV;
   TopExp::MapShapesAndAncestors(shell, TopAbs_VERTEX, TopAbs_FACE, MV);
-  
+
   for (i=1; i<=nbSects-1; i++) {
-    
+
     const TopoDS_Wire& wire1 = TopoDS::Wire(myWires(i));
     const TopoDS_Wire& wire2 = TopoDS::Wire(myWires(i+1));
-    
+
     anExp1.Init(wire1);
     anExp2.Init(wire2);
 
@@ -489,51 +489,51 @@ void BRepOffsetAPI_ThruSections::CreateRuled()
       const TopoDS_Shape& edge2 = anExp2.Current();
       Standard_Boolean degen1 = BRep_Tool::Degenerated(anExp1.Current());
       Standard_Boolean degen2 = BRep_Tool::Degenerated(anExp2.Current());
-      
+
       TopTools_MapOfShape MapFaces;
       if (degen2){
-       TopoDS_Vertex Vdegen = TopExp::FirstVertex(TopoDS::Edge(edge2));
-       for (it.Initialize(MV.FindFromKey(Vdegen)); it.More(); it.Next()) {
-         MapFaces.Add(it.Value());
-       }
+        TopoDS_Vertex Vdegen = TopExp::FirstVertex(TopoDS::Edge(edge2));
+        for (it.Initialize(MV.FindFromKey(Vdegen)); it.More(); it.Next()) {
+          MapFaces.Add(it.Value());
+        }
       }
       else {
-       for (it.Initialize(M.FindFromKey(edge2)); it.More(); it.Next()) {
-         MapFaces.Add(it.Value());
-       }
+        for (it.Initialize(M.FindFromKey(edge2)); it.More(); it.Next()) {
+          MapFaces.Add(it.Value());
+        }
       }
-      
+
       if (degen1) {
-       TopoDS_Vertex Vdegen = TopExp::FirstVertex(TopoDS::Edge(edge1));
-       for (it.Initialize(MV.FindFromKey(Vdegen)); it.More(); it.Next()) {
-         const TopoDS_Shape& Face = it.Value();
-         if (MapFaces.Contains(Face)) {
-           myGenerated.Bind(edge1, Face);
-           break;
-         }
-       }
+        TopoDS_Vertex Vdegen = TopExp::FirstVertex(TopoDS::Edge(edge1));
+        for (it.Initialize(MV.FindFromKey(Vdegen)); it.More(); it.Next()) {
+          const TopoDS_Shape& Face = it.Value();
+          if (MapFaces.Contains(Face)) {
+            myGenerated.Bind(edge1, Face);
+            break;
+          }
+        }
       }
       else {
-       for (it.Initialize(M.FindFromKey(edge1)); it.More(); it.Next()) {
-         const TopoDS_Shape& Face = it.Value();
-         if (MapFaces.Contains(Face)) {
-           myGenerated.Bind(edge1, Face);
-           break;
-         }
-       }
+        for (it.Initialize(M.FindFromKey(edge1)); it.More(); it.Next()) {
+          const TopoDS_Shape& Face = it.Value();
+          if (MapFaces.Contains(Face)) {
+            myGenerated.Bind(edge1, Face);
+            break;
+          }
+        }
       }
-      
+
       if (!degen1) anExp1.Next();
       if (!degen2) anExp2.Next();
-      
+
       tantque = anExp1.More() && anExp2.More();
       if (degen1) tantque = anExp2.More();
       if (degen2) tantque = anExp1.More();
-      
+
     }
-      
+
   }
-      
+
 }
 
 //=======================================================================
@@ -593,15 +593,15 @@ void BRepOffsetAPI_ThruSections::CreateSmoothed()
       // if the wire is punctual
       anExp.Init(TopoDS::Wire(wire));
       for(j=1; j<=nbEdges; j++) {
-       nb++;
-       shapes(nb) = anExp.Current();
+        nb++;
+        shapes(nb) = anExp.Current();
       }
     }
     else {
       // otherwise
       for(anExp.Init(TopoDS::Wire(wire)); anExp.More(); anExp.Next()) {
-       nb++;
-       shapes(nb) = anExp.Current();
+        nb++;
+        shapes(nb) = anExp.Current();
       }
     }
   }
@@ -667,17 +667,17 @@ void BRepOffsetAPI_ThruSections::CreateSmoothed()
 
     // make the wire
     B.MakeWire(W);
-    
+
     // make the missing edges
     Standard_Real f1, f2, l1, l2;
     surface->Bounds(f1,l1,f2,l2);
-  
+
     // --- edge 1
     if ( w1Point ) {
       // copy the degenerated edge
       TopoDS_Shape aLocalShape = shapes(1).EmptyCopied();
       edge1 =  TopoDS::Edge(aLocalShape);
-//      edge1 =  TopoDS::Edge(shapes(1).EmptyCopied());
+      //      edge1 =  TopoDS::Edge(shapes(1).EmptyCopied());
       edge1.Orientation(TopAbs_FORWARD);
     }
     else {
@@ -692,21 +692,21 @@ void BRepOffsetAPI_ThruSections::CreateSmoothed()
     // store edges of the 1st section
     if (vClosed)
       vcouture(i) = edge1;
-    
+
 
     // --- edge 2
     if (vClosed)
       edge2 = TopoDS::Edge(vcouture(i));
     else {
       if ( w2Point ) {
-       // copy of the degenerated edge
-       TopoDS_Shape aLocalShape = shapes(nbSects*nbEdges).EmptyCopied();
-       edge2 =  TopoDS::Edge(aLocalShape);
-//     edge2 =  TopoDS::Edge(shapes(nbSects*nbEdges).EmptyCopied());
-       edge2.Orientation(TopAbs_FORWARD);
+        // copy of the degenerated edge
+        TopoDS_Shape aLocalShape = shapes(nbSects*nbEdges).EmptyCopied();
+        edge2 =  TopoDS::Edge(aLocalShape);
+        //     edge2 =  TopoDS::Edge(shapes(nbSects*nbEdges).EmptyCopied());
+        edge2.Orientation(TopAbs_FORWARD);
       }
       else {
-       B.MakeEdge(edge2, surface->VIso(l2), Precision::Confusion());
+        B.MakeEdge(edge2, surface->VIso(l2), Precision::Confusion());
       }
       v2f.Orientation(TopAbs_FORWARD);
       B.Add(edge2, v2f);
@@ -726,7 +726,7 @@ void BRepOffsetAPI_ThruSections::CreateSmoothed()
       B.Add(edge3, v2f);
       B.Range(edge3, f2, l2);
       if (uClosed) {
-       couture = edge3;
+        couture = edge3;
       }
     }
     else {
@@ -755,34 +755,34 @@ void BRepOffsetAPI_ThruSections::CreateSmoothed()
     // set PCurve
     if (vClosed) {
       B.UpdateEdge(edge1,
-                  new Geom2d_Line(gp_Pnt2d(0,f2),gp_Dir2d(1,0)),
-                  new Geom2d_Line(gp_Pnt2d(0,l2),gp_Dir2d(1,0)),face,
-                  Precision::Confusion());
+        new Geom2d_Line(gp_Pnt2d(0,f2),gp_Dir2d(1,0)),
+        new Geom2d_Line(gp_Pnt2d(0,l2),gp_Dir2d(1,0)),face,
+        Precision::Confusion());
       B.Range(edge1,face,f1,l1);
     }
     else {
       B.UpdateEdge(edge1,new Geom2d_Line(gp_Pnt2d(0,f2),gp_Dir2d(1,0)),face,
-                  Precision::Confusion());
+        Precision::Confusion());
       B.Range(edge1,face,f1,l1);
       B.UpdateEdge(edge2,new Geom2d_Line(gp_Pnt2d(0,l2),gp_Dir2d(1,0)),face,
-                  Precision::Confusion());
+        Precision::Confusion());
       B.Range(edge2,face,f1,l1);
     }
 
     if ( uClosed && nbEdges ==1 )  {
       B.UpdateEdge(edge3,
-                  new Geom2d_Line(gp_Pnt2d(l1,0),gp_Dir2d(0,1)),
-                  new Geom2d_Line(gp_Pnt2d(f1,0),gp_Dir2d(0,1)),face,
-                  Precision::Confusion());
+        new Geom2d_Line(gp_Pnt2d(l1,0),gp_Dir2d(0,1)),
+        new Geom2d_Line(gp_Pnt2d(f1,0),gp_Dir2d(0,1)),face,
+        Precision::Confusion());
       B.Range(edge3,face,f2,l2);
 
     }
     else {
       B.UpdateEdge(edge3,new Geom2d_Line(gp_Pnt2d(f1,0),gp_Dir2d(0,1)),face,
-                  Precision::Confusion());
+        Precision::Confusion());
       B.Range(edge3,face,f2,l2);
       B.UpdateEdge(edge4,new Geom2d_Line(gp_Pnt2d(l1,0),gp_Dir2d(0,1)),face,
-                  Precision::Confusion());
+        Precision::Confusion());
       B.Range(edge4,face,f2,l2);
     }
     B.Add(face,W);
@@ -811,15 +811,15 @@ void BRepOffsetAPI_ThruSections::CreateSmoothed()
       BRep_Builder B;
       B.MakeSolid(solid); 
       B.Add(solid, shell);
-      
+
       // verify the orientation the solid
       BRepClass3d_SolidClassifier clas3d(solid);
       clas3d.PerformInfinitePoint(Precision::Confusion());
       if (clas3d.State() == TopAbs_IN) {
-       B.MakeSolid(solid); 
-       TopoDS_Shape aLocalShape = shell.Reversed();
-       B.Add(solid, TopoDS::Shell(aLocalShape));
-//     B.Add(solid, TopoDS::Shell(shell.Reversed()));
+        B.MakeSolid(solid); 
+        TopoDS_Shape aLocalShape = shell.Reversed();
+        B.Add(solid, TopoDS::Shell(aLocalShape));
+        //     B.Add(solid, TopoDS::Shell(shell.Reversed()));
       }
       myShape = solid;
 
@@ -836,7 +836,7 @@ void BRepOffsetAPI_ThruSections::CreateSmoothed()
     myShape = shell;
     Done();
   }
-  
+
   TopExp_Explorer ex(myShape,TopAbs_EDGE);
   while (ex.More()) {
     const TopoDS_Edge& CurE = TopoDS::Edge(ex.Current());
@@ -924,15 +924,14 @@ static Handle(Geom_BSplineCurve) EdgeToBSpline (const TopoDS_Edge& theEdge)
 //=======================================================================
 
 Handle(Geom_BSplineSurface) BRepOffsetAPI_ThruSections::
-                                   TotalSurf(const TopTools_Array1OfShape& shapes,
-                                            const Standard_Integer NbSects,
-                                            const Standard_Integer NbEdges,
-                                            const Standard_Boolean w1Point,
-                                            const Standard_Boolean w2Point,
-                                            const Standard_Boolean vClosed) const
+                          TotalSurf(const TopTools_Array1OfShape& shapes,
+                                    const Standard_Integer NbSects,
+                                    const Standard_Integer NbEdges,
+                                    const Standard_Boolean w1Point,
+                                    const Standard_Boolean w2Point,
+                                    const Standard_Boolean vClosed) const
 {
   Standard_Integer i,j,jdeb=1,jfin=NbSects;
-  TopoDS_Edge edge;
   TopoDS_Vertex vf,vl;
 
   GeomFill_SectionGenerator section;
@@ -943,7 +942,7 @@ Handle(Geom_BSplineSurface) BRepOffsetAPI_ThruSections::
 
   if (w1Point) {
     jdeb++;
-    edge =  TopoDS::Edge(shapes(1));
+    TopoDS_Edge edge =  TopoDS::Edge(shapes(1));
     TopExp::Vertices(edge,vl,vf);
     TColgp_Array1OfPnt Extremities(1,2);
     Extremities(1) = BRep_Tool::Pnt(vf);
@@ -979,12 +978,17 @@ Handle(Geom_BSplineSurface) BRepOffsetAPI_ThruSections::
       GeomConvert_CompCurveToBSplineCurve CompBS(curvBS);
 
       for (i=2; i<=NbEdges; i++) {  
-       // read the edge
+        // read the edge
         TopoDS_Edge aNextEdge = TopoDS::Edge (shapes((j-1)*NbEdges+i));
+        Standard_Real aTolV = Precision::Confusion();  
+        TopExp::Vertices(aNextEdge,vf,vl);
+        aTolV = Max(aTolV, BRep_Tool::Tolerance(vf));
+        aTolV = Max(aTolV, BRep_Tool::Tolerance(vl));
+        aTolV = Min(aTolV, 1.e-3);
         curvBS = EdgeToBSpline (aNextEdge);
 
-       // concatenation
-       CompBS.Add(curvBS, Precision::Confusion(), Standard_True, Standard_False, 1);
+        // concatenation
+        CompBS.Add(curvBS, aTolV, Standard_True, Standard_False, 1);
       }
 
       // return the final section
@@ -993,14 +997,14 @@ Handle(Geom_BSplineSurface) BRepOffsetAPI_ThruSections::
 
       // case of looping sections
       if (j==jdeb && vClosed) {
-       BS1 = BS;
+        BS1 = BS;
       }
 
     }
   }
 
   if (w2Point) {
-    edge =  TopoDS::Edge(shapes(NbSects*NbEdges));
+    TopoDS_Edge edge =  TopoDS::Edge(shapes(NbSects*NbEdges));
     TopExp::Vertices(edge,vl,vf);
     TColgp_Array1OfPnt Extremities(1,2);
     Extremities(1) = BRep_Tool::Pnt(vf);
@@ -1040,13 +1044,13 @@ Handle(Geom_BSplineSurface) BRepOffsetAPI_ThruSections::
   if(anApprox.IsDone()) {
     surface = 
       new Geom_BSplineSurface(anApprox.SurfPoles(), anApprox.SurfWeights(),
-                           anApprox.SurfUKnots(), anApprox.SurfVKnots(),
-                           anApprox.SurfUMults(), anApprox.SurfVMults(),
-                           anApprox.UDegree(), anApprox.VDegree());
+      anApprox.SurfUKnots(), anApprox.SurfVKnots(),
+      anApprox.SurfUMults(), anApprox.SurfVMults(),
+      anApprox.UDegree(), anApprox.VDegree());
   }
 
   return surface;
-  
+
 }
 
 //=======================================================================