--- /dev/null
+diff --git a/adm/cmake/occt_resources.cmake b/adm/cmake/occt_resources.cmake
+index 7a88051..d51df4d 100644
+--- a/adm/cmake/occt_resources.cmake
++++ b/adm/cmake/occt_resources.cmake
+@@ -68,6 +68,7 @@ FILE_TO_LIST ("adm/RESOURCES" RESOURCES)
+ foreach (CurrentResource ${RESOURCES})
+ get_filename_component (CurrentResource_FileName "${CurrentResource}" NAME)
+ if ("${CurrentResource_FileName}" STREQUAL TObj.msg OR
++ "${CurrentResource_FileName}" STREQUAL BOPAlgo.msg OR
+ "${CurrentResource_FileName}" STREQUAL Units.dat OR
+ "${CurrentResource}" STREQUAL XSMessage OR
+ "${CurrentResource}" STREQUAL SHMessage OR
+diff --git a/src/BOPAlgo/BOPAlgo.msg b/src/BOPAlgo/BOPAlgo.msg
+index 67350fc..673a39e 100644
+--- a/src/BOPAlgo/BOPAlgo.msg
++++ b/src/BOPAlgo/BOPAlgo.msg
+@@ -67,3 +67,12 @@ Warning: Removal of internal boundaries among Faces has failed
+
+ .BOPAlgo_AlertRemovalOfIBForEdgesFailed
+ Warning: Removal of internal boundaries among Edges has failed
++
++.BOPAlgo_AlertIntersectionOfPairOfShapesFailed
++Warning: Intersection of pair of shapes has failed
++
++.BOPAlgo_AlertBuildingPCurveFailed
++Warning: Building 2D curve of edge on face has failed
++
++.BOPAlgo_AlertAcquiredSelfIntersection
++Warning: Some sub-shapes of some of the argument become connected through other shapes and the argument became self-interfered
+diff --git a/src/BOPAlgo/BOPAlgo_Alerts.hxx b/src/BOPAlgo/BOPAlgo_Alerts.hxx
+index 02cec15..04ce9c7 100644
+--- a/src/BOPAlgo/BOPAlgo_Alerts.hxx
++++ b/src/BOPAlgo/BOPAlgo_Alerts.hxx
+@@ -78,4 +78,14 @@ DEFINE_ALERT_WITH_SHAPE(BOPAlgo_AlertShellSplitterFailed)
+ //! Some edges are too small and have no valid range
+ DEFINE_ALERT_WITH_SHAPE(BOPAlgo_AlertTooSmallEdge)
+
++//! Intersection of pair of shapes has failed
++DEFINE_ALERT_WITH_SHAPE(BOPAlgo_AlertIntersectionOfPairOfShapesFailed)
++
++//! Building 2D curve of edge on face has failed
++DEFINE_ALERT_WITH_SHAPE(BOPAlgo_AlertBuildingPCurveFailed)
++
++//! Some sub-shapes of some of the argument become connected through
++//! other shapes and the argument became self-interfered
++DEFINE_ALERT_WITH_SHAPE(BOPAlgo_AlertAcquiredSelfIntersection)
++
+ #endif // _BOPAlgo_Alerts_HeaderFile
+diff --git a/src/BOPAlgo/BOPAlgo_BOPAlgo_msg.pxx b/src/BOPAlgo/BOPAlgo_BOPAlgo_msg.pxx
+index c63a538..feec778 100644
+--- a/src/BOPAlgo/BOPAlgo_BOPAlgo_msg.pxx
++++ b/src/BOPAlgo/BOPAlgo_BOPAlgo_msg.pxx
+@@ -69,4 +69,13 @@ static const char BOPAlgo_BOPAlgo_msg[] =
+ "Warning: Removal of internal boundaries among Faces has failed\n"
+ "\n"
+ ".BOPAlgo_AlertRemovalOfIBForEdgesFailed\n"
+- "Warning: Removal of internal boundaries among Edges has failed\n";
++ "Warning: Removal of internal boundaries among Edges has failed\n"
++ "\n"
++ ".BOPAlgo_AlertIntersectionOfPairOfShapesFailed\n"
++ "Warning: Intersection of pair of shapes has failed\n"
++ "\n"
++ ".BOPAlgo_AlertBuildingPCurveFailed\n"
++ "Warning: Building 2D curve of edge on face has failed\n"
++ "\n"
++ ".BOPAlgo_AlertAcquiredSelfIntersection\n"
++ "Warning: Some sub-shapes of some of the argument become connected through other shapes and the argument became self-interfered\n";
+diff --git a/src/BOPAlgo/BOPAlgo_PaveFiller.hxx b/src/BOPAlgo/BOPAlgo_PaveFiller.hxx
+index ab79f4e..bd4e512 100644
+--- a/src/BOPAlgo/BOPAlgo_PaveFiller.hxx
++++ b/src/BOPAlgo/BOPAlgo_PaveFiller.hxx
+@@ -87,13 +87,19 @@ class TopoDS_Face;
+ //! - *Gluing options* - allows to speed up the calculation on the special
+ //! cases, in which some sub-shapes are coincide.<br>
+ //!
+-//! The algorithm returns the following Warning statuses:<br>
+-//! - *BOPAlgo_AlertSelfInterferingShape* - in case some of the argument shapes are self-interfering shapes;<br>
+-//! - *BOPAlgo_AlertTooSmallEdge* - in case some edges of the input shapes have no valid range;<br>
++//! The algorithm returns the following Warning statuses:
++//! - *BOPAlgo_AlertSelfInterferingShape* - in case some of the argument shapes are self-interfering shapes;
++//! - *BOPAlgo_AlertTooSmallEdge* - in case some edges of the input shapes have no valid range;
+ //! - *BOPAlgo_AlertNotSplittableEdge* - in case some edges of the input shapes has such a small
+-//! valid range so it cannot be split;<br>
++//! valid range so it cannot be split;
+ //! - *BOPAlgo_AlertBadPositioning* - in case the positioning of the input shapes leads to creation
+-//! of small edges.<br>
++//! of small edges;
++//! - *BOPAlgo_AlertIntersectionOfPairOfShapesFailed* - in case intersection of some of the
++//! sub-shapes has failed;
++//! - *BOPAlgo_AlertAcquiredSelfIntersection* - in case some sub-shapes of the argument become connected
++//! through other shapes;
++//! - *BOPAlgo_AlertBuildingPCurveFailed* - in case building 2D curve for some of the edges
++//! on the faces has failed.
+ //!
+ //! The algorithm returns the following Error alerts:
+ //! - *BOPAlgo_AlertTooFewArguments* - in case there are no enough arguments to
+@@ -290,6 +296,7 @@ protected:
+ BOPDS_DataMapOfPaveBlockListOfPaveBlock& theDMExEdges,
+ BOPCol_DataMapOfIntegerInteger& theDMNewSD,
+ const BOPCol_IndexedMapOfShape& theMicroEdges,
++ const BOPCol_IndexedMapOfShape& theVertsOnRejectedPB,
+ const BOPCol_BaseAllocator& theAllocator);
+
+ Standard_EXPORT void FindPaveBlocks (const Standard_Integer theV, const Standard_Integer theF, BOPDS_ListOfPaveBlock& theLPB);
+@@ -474,6 +481,8 @@ protected:
+ //! In case self-interference is found the warning is added.
+ Standard_EXPORT void CheckSelfInterference();
+
++ //! Adds the warning about failed intersection of pair of sub-shapes
++ Standard_EXPORT void AddIntersectionFailedWarning(const TopoDS_Shape& theS1, const TopoDS_Shape& theS2);
+
+ BOPCol_ListOfShape myArguments;
+ BOPDS_PDS myDS;
+diff --git a/src/BOPAlgo/BOPAlgo_PaveFiller_11.cxx b/src/BOPAlgo/BOPAlgo_PaveFiller_11.cxx
+index c8341c5..83faf2d 100644
+--- a/src/BOPAlgo/BOPAlgo_PaveFiller_11.cxx
++++ b/src/BOPAlgo/BOPAlgo_PaveFiller_11.cxx
+@@ -112,7 +112,8 @@ void BOPAlgo_PaveFiller::CheckSelfInterference()
+ }
+ //
+ if (aLE.Extent() > 1) {
+- // Add warning
++ // Add the acquired self-interference warning:
++ // The same common block contains several edges from one argument
+ TopoDS_Compound aWC;
+ aBB.MakeCompound(aWC);
+ //
+@@ -122,7 +123,7 @@ void BOPAlgo_PaveFiller::CheckSelfInterference()
+ aBB.Add(aWC, aE1);
+ }
+ //
+- AddWarning (new BOPAlgo_AlertSelfInterferingShape (aWC));
++ AddWarning (new BOPAlgo_AlertAcquiredSelfIntersection (aWC));
+ }
+ }
+ }
+@@ -168,7 +169,8 @@ void BOPAlgo_PaveFiller::CheckSelfInterference()
+ for (j = 1; j <= aNbC; ++j) {
+ const BOPCol_IndexedMapOfShape& aMCS = aMCSI(j);
+ if (aMCS.Extent() > 1) {
+- // Add self-interference warning
++ // Add acquired self-interference warning:
++ // Several faces from one argument contain the same vertex or edge
+ TopoDS_Compound aWC;
+ aBB.MakeCompound(aWC);
+ //
+@@ -177,7 +179,7 @@ void BOPAlgo_PaveFiller::CheckSelfInterference()
+ const TopoDS_Shape& aSx = aMCS(iS);
+ aBB.Add(aWC, aSx);
+ }
+- AddWarning (new BOPAlgo_AlertSelfInterferingShape (aWC));
++ AddWarning (new BOPAlgo_AlertAcquiredSelfIntersection (aWC));
+ }
+ }
+ }
+diff --git a/src/BOPAlgo/BOPAlgo_PaveFiller_2.cxx b/src/BOPAlgo/BOPAlgo_PaveFiller_2.cxx
+index c496668..9ac5e67 100644
+--- a/src/BOPAlgo/BOPAlgo_PaveFiller_2.cxx
++++ b/src/BOPAlgo/BOPAlgo_PaveFiller_2.cxx
+@@ -17,6 +17,7 @@
+
+
+ #include <BOPAlgo_PaveFiller.hxx>
++#include <BOPAlgo_Alerts.hxx>
+ #include <BOPAlgo_Tools.hxx>
+ #include <BOPCol_NCVector.hxx>
+ #include <BOPCol_Parallel.hxx>
+@@ -27,6 +28,7 @@
+ #include <BOPDS_PaveBlock.hxx>
+ #include <BOPDS_VectorOfInterfVE.hxx>
+ #include <BOPTools_AlgoTools.hxx>
++#include <BRep_Builder.hxx>
+ #include <BRep_Tool.hxx>
+ #include <gp_Pnt.hxx>
+ #include <IntTools_Context.hxx>
+@@ -110,7 +112,16 @@ class BOPAlgo_VertexEdge : public BOPAlgo_Algo {
+ //
+ virtual void Perform() {
+ BOPAlgo_Algo::UserBreak();
+- myFlag=myContext->ComputeVE (myV, myE, myT, myTolVNew, myFuzzyValue);
++ try
++ {
++ OCC_CATCH_SIGNALS
++
++ myFlag=myContext->ComputeVE (myV, myE, myT, myTolVNew, myFuzzyValue);
++ }
++ catch (Standard_Failure)
++ {
++ AddError(new BOPAlgo_AlertIntersectionFailed);
++ }
+ };
+ //
+ protected:
+@@ -267,6 +278,11 @@ void BOPAlgo_PaveFiller::IntersectVE
+ for (i = 0; i < aNbVE; ++i) {
+ const BOPAlgo_VertexEdge& aVESolver = aVVE(i);
+ if (aVESolver.Flag() != 0) {
++ if (aVESolver.HasErrors())
++ {
++ // Warn about failed intersection of sub-shapes
++ AddIntersectionFailedWarning(aVESolver.Vertex(), aVESolver.Edge());
++ }
+ continue;
+ }
+ //
+@@ -491,3 +507,19 @@ void BOPAlgo_PaveFiller::SplitPaveBlocks(const BOPCol_MapOfInteger& theMEdges,
+ }
+ }
+ }
++
++//=======================================================================
++// function: AddIntersectionFailedWarning
++// purpose:
++//=======================================================================
++void BOPAlgo_PaveFiller::AddIntersectionFailedWarning(const TopoDS_Shape& theS1,
++ const TopoDS_Shape& theS2)
++{
++ // Create the warn shape
++ TopoDS_Compound aWC;
++ BRep_Builder().MakeCompound(aWC);
++ BRep_Builder().Add(aWC, theS1);
++ BRep_Builder().Add(aWC, theS2);
++ // Add the warning
++ AddWarning(new BOPAlgo_AlertIntersectionOfPairOfShapesFailed(aWC));
++}
+\ No newline at end of file
+diff --git a/src/BOPAlgo/BOPAlgo_PaveFiller_3.cxx b/src/BOPAlgo/BOPAlgo_PaveFiller_3.cxx
+index 3a8892e..5db97a8 100644
+--- a/src/BOPAlgo/BOPAlgo_PaveFiller_3.cxx
++++ b/src/BOPAlgo/BOPAlgo_PaveFiller_3.cxx
+@@ -93,7 +93,16 @@ class BOPAlgo_EdgeEdge :
+ //
+ virtual void Perform() {
+ BOPAlgo_Algo::UserBreak();
+- IntTools_EdgeEdge::Perform();
++ try
++ {
++ OCC_CATCH_SIGNALS
++
++ IntTools_EdgeEdge::Perform();
++ }
++ catch (Standard_Failure)
++ {
++ AddError(new BOPAlgo_AlertIntersectionFailed);
++ }
+ }
+ //
+ protected:
+@@ -229,7 +238,11 @@ void BOPAlgo_PaveFiller::PerformEE()
+ Bnd_Box aBB1, aBB2;
+ //
+ BOPAlgo_EdgeEdge& anEdgeEdge=aVEdgeEdge(k);
+- if (!anEdgeEdge.IsDone()) {
++ if (!anEdgeEdge.IsDone() || anEdgeEdge.HasErrors()) {
++ // Warn about failed intersection of sub-shapes
++ const TopoDS_Shape& aE1 = myDS->Shape(anEdgeEdge.PaveBlock1()->OriginalEdge());
++ const TopoDS_Shape& aE2 = myDS->Shape(anEdgeEdge.PaveBlock2()->OriginalEdge());
++ AddIntersectionFailedWarning(aE1, aE2);
+ continue;
+ }
+ //
+diff --git a/src/BOPAlgo/BOPAlgo_PaveFiller_4.cxx b/src/BOPAlgo/BOPAlgo_PaveFiller_4.cxx
+index 291edb2..900d363 100644
+--- a/src/BOPAlgo/BOPAlgo_PaveFiller_4.cxx
++++ b/src/BOPAlgo/BOPAlgo_PaveFiller_4.cxx
+@@ -17,6 +17,7 @@
+
+
+ #include <BOPAlgo_PaveFiller.hxx>
++#include <BOPAlgo_Alerts.hxx>
+ #include <BOPAlgo_SectionAttribute.hxx>
+ #include <BOPCol_MapOfInteger.hxx>
+ #include <BOPCol_NCVector.hxx>
+@@ -107,7 +108,16 @@ class BOPAlgo_VertexFace : public BOPAlgo_Algo {
+ //
+ virtual void Perform() {
+ BOPAlgo_Algo::UserBreak();
+- myFlag=myContext->ComputeVF(myV, myF, myT1, myT2, myTolVNew, myFuzzyValue);
++ try
++ {
++ OCC_CATCH_SIGNALS
++
++ myFlag=myContext->ComputeVF(myV, myF, myT1, myT2, myTolVNew, myFuzzyValue);
++ }
++ catch (Standard_Failure)
++ {
++ AddError(new BOPAlgo_AlertIntersectionFailed);
++ }
+ }
+ //
+ protected:
+@@ -212,7 +222,12 @@ void BOPAlgo_PaveFiller::PerformVF()
+ const BOPAlgo_VertexFace& aVertexFace=aVVF(k);
+ //
+ iFlag=aVertexFace.Flag();
+- if (iFlag) {
++ if (iFlag != 0) {
++ if (aVertexFace.HasErrors())
++ {
++ // Warn about failed intersection of sub-shapes
++ AddIntersectionFailedWarning(aVertexFace.Vertex(), aVertexFace.Face());
++ }
+ continue;
+ }
+ //
+diff --git a/src/BOPAlgo/BOPAlgo_PaveFiller_5.cxx b/src/BOPAlgo/BOPAlgo_PaveFiller_5.cxx
+index 84fc6d1..717e478 100644
+--- a/src/BOPAlgo/BOPAlgo_PaveFiller_5.cxx
++++ b/src/BOPAlgo/BOPAlgo_PaveFiller_5.cxx
+@@ -103,7 +103,16 @@ class BOPAlgo_EdgeFace :
+ //
+ virtual void Perform() {
+ BOPAlgo_Algo::UserBreak();
+- IntTools_EdgeFace::Perform();
++ try
++ {
++ OCC_CATCH_SIGNALS
++
++ IntTools_EdgeFace::Perform();
++ }
++ catch (Standard_Failure)
++ {
++ AddError(new BOPAlgo_AlertIntersectionFailed);
++ }
+ }
+ //
+ protected:
+@@ -258,7 +267,9 @@ void BOPAlgo_PaveFiller::PerformEF()
+ //
+ for (k=0; k < aNbEdgeFace; ++k) {
+ BOPAlgo_EdgeFace& aEdgeFace=aVEdgeFace(k);
+- if (!aEdgeFace.IsDone()) {
++ if (!aEdgeFace.IsDone() || aEdgeFace.HasErrors()) {
++ // Warn about failed intersection of sub-shapes
++ AddIntersectionFailedWarning(aEdgeFace.Edge(), aEdgeFace.Face());
+ continue;
+ }
+ //
+diff --git a/src/BOPAlgo/BOPAlgo_PaveFiller_6.cxx b/src/BOPAlgo/BOPAlgo_PaveFiller_6.cxx
+index bbc1b35..dfbfe61 100644
+--- a/src/BOPAlgo/BOPAlgo_PaveFiller_6.cxx
++++ b/src/BOPAlgo/BOPAlgo_PaveFiller_6.cxx
+@@ -144,7 +144,16 @@ class BOPAlgo_FaceFace :
+ //
+ virtual void Perform() {
+ BOPAlgo_Algo::UserBreak();
+- IntTools_FaceFace::Perform(myF1, myF2);
++ try
++ {
++ OCC_CATCH_SIGNALS
++
++ IntTools_FaceFace::Perform(myF1, myF2);
++ }
++ catch (Standard_Failure)
++ {
++ AddError(new BOPAlgo_AlertIntersectionFailed);
++ }
+ }
+ //
+ protected:
+@@ -263,10 +272,12 @@ void BOPAlgo_PaveFiller::PerformFF()
+ for (k = 0; k < aNbFaceFace; ++k) {
+ BOPAlgo_FaceFace& aFaceFace = aVFaceFace(k);
+ aFaceFace.Indices(nF1, nF2);
+- if (!aFaceFace.IsDone()) {
++ if (!aFaceFace.IsDone() || aFaceFace.HasErrors()) {
+ BOPDS_InterfFF& aFF = aFFs.Append1();
+ aFF.SetIndices(nF1, nF2);
+ aFF.Init(0, 0);
++ // Warn about failed intersection of faces
++ AddIntersectionFailedWarning(aFaceFace.Face1(), aFaceFace.Face2());
+ continue;
+ }
+ //
+@@ -373,6 +384,7 @@ void BOPAlgo_PaveFiller::MakeBlocks()
+ BOPCol_DataMapOfIntegerListOfInteger aDMBV(100, aAllocator);
+ BOPCol_DataMapIteratorOfDataMapOfIntegerReal aItMV;
+ BOPCol_IndexedMapOfShape aMicroEdges(100, aAllocator);
++ BOPCol_IndexedMapOfShape aVertsOnRejectedPB;
+ //
+ for (i=0; i<aNbFF; ++i) {
+ //
+@@ -557,6 +569,19 @@ void BOPAlgo_PaveFiller::MakeBlocks()
+ if (!bInBothFaces) {
+ aMPBAdd.Add(aPBOut);
+ PreparePostTreatFF(i, j, aPBOut, aMSCPB, aMVI, aLPBC);
++ // Try fusing the vertices of the existing pave block
++ // with the vertices put on the real section curve (except
++ // for technological vertices, which will be removed)
++ Standard_Integer nVOut1, nVOut2;
++ aPBOut->Indices(nVOut1, nVOut2);
++ if (nV1 != nVOut1 && nV1 != nVOut2 && !aMVBounds.Contains(nV1))
++ {
++ aVertsOnRejectedPB.Add(aV1);
++ }
++ if (nV2 != nVOut1 && nV2 != nVOut2 && !aMVBounds.Contains(nV2))
++ {
++ aVertsOnRejectedPB.Add(aV2);
++ }
+ }
+ }
+ continue;
+@@ -639,7 +664,7 @@ void BOPAlgo_PaveFiller::MakeBlocks()
+ //
+ // post treatment
+ MakeSDVerticesFF(aDMVLV, aDMNewSD);
+- PostTreatFF(aMSCPB, aDMExEdges, aDMNewSD, aMicroEdges, aAllocator);
++ PostTreatFF(aMSCPB, aDMExEdges, aDMNewSD, aMicroEdges, aVertsOnRejectedPB, aAllocator);
+ if (HasErrors()) {
+ return;
+ }
+@@ -697,6 +722,7 @@ void BOPAlgo_PaveFiller::PostTreatFF
+ BOPDS_DataMapOfPaveBlockListOfPaveBlock& aDMExEdges,
+ BOPCol_DataMapOfIntegerInteger& aDMNewSD,
+ const BOPCol_IndexedMapOfShape& theMicroEdges,
++ const BOPCol_IndexedMapOfShape& theVertsOnRejectedPB,
+ const Handle(NCollection_BaseAllocator)& theAllocator)
+ {
+ Standard_Integer aNbS = theMSCPB.Extent();
+@@ -724,8 +750,9 @@ void BOPAlgo_PaveFiller::PostTreatFF
+ BOPDS_VectorOfInterfFF& aFFs=myDS->InterfFF();
+ //
+ Standard_Integer aNbME = theMicroEdges.Extent();
++ Standard_Integer aNbVOnRPB = theVertsOnRejectedPB.Extent();
+ // 0
+- if (aNbS==1 && (aNbME == 0)) {
++ if (aNbS==1 && (aNbME == 0) && (aNbVOnRPB == 0)) {
+ const TopoDS_Shape& aS=theMSCPB.FindKey(1);
+ const BOPDS_CoupleOfPaveBlocks &aCPB=theMSCPB.FindFromIndex(1);
+ //
+@@ -824,6 +851,20 @@ void BOPAlgo_PaveFiller::PostTreatFF
+ aBB.UpdateVertex(aVerts[1], aTolV2 + aDist);
+ }
+ }
++
++ // Add vertices put on the real section curves to unify them with the
++ // vertices of the edges, by which these sections curves have been rejected
++ for (Standard_Integer i = 1; i <= aNbVOnRPB; ++i)
++ {
++ TopoDS_Shape aVer = theVertsOnRejectedPB(i);
++ Standard_Integer iVer = myDS->Index(aVer);
++ const Standard_Integer* pSD = aDMNewSD.Seek(iVer);
++ if (pSD)
++ aVer = myDS->Shape(*pSD);
++
++ if (anAddedSD.Add(aVer))
++ aLS.Append(aVer);
++ }
+ //
+ // 2 Fuse shapes
+ aPF.SetProgressIndicator(myProgressIndicator);
+diff --git a/src/BOPAlgo/BOPAlgo_PaveFiller_7.cxx b/src/BOPAlgo/BOPAlgo_PaveFiller_7.cxx
+index bf02175..1e91f55 100644
+--- a/src/BOPAlgo/BOPAlgo_PaveFiller_7.cxx
++++ b/src/BOPAlgo/BOPAlgo_PaveFiller_7.cxx
+@@ -16,6 +16,7 @@
+ // commercial license or contractual agreement.
+
+ #include <BOPAlgo_PaveFiller.hxx>
++#include <BOPAlgo_Alerts.hxx>
+ #include <BOPAlgo_SectionAttribute.hxx>
+ #include <BOPAlgo_Tools.hxx>
+ #include <BOPCol_IndexedMapOfShape.hxx>
+@@ -241,28 +242,37 @@ class BOPAlgo_MPC : public BOPAlgo_Algo {
+ }
+ //
+ virtual void Perform() {
+- Standard_Integer iErr;
+- //
+- iErr=1;
+- if (!myEz.IsNull()) {
+- TopoDS_Edge aSpz;
++ try
++ {
++ OCC_CATCH_SIGNALS
++
++ Standard_Integer iErr;
+ //
+- BOPTools_AlgoTools::MakeSplitEdge(myEz,myV1, myT1,
+- myV2, myT2, aSpz);
++ iErr=1;
++ if (!myEz.IsNull()) {
++ TopoDS_Edge aSpz;
++ //
++ BOPTools_AlgoTools::MakeSplitEdge(myEz,myV1, myT1,
++ myV2, myT2, aSpz);
++ //
++ iErr=
++ BOPTools_AlgoTools2D::AttachExistingPCurve(aSpz,
++ myE,
++ myF,
++ myContext);
++ }
+ //
+- iErr=
+- BOPTools_AlgoTools2D::AttachExistingPCurve(aSpz,
+- myE,
+- myF,
+- myContext);
+- }
+- //
+- if (iErr) {
+- BOPTools_AlgoTools2D::BuildPCurveForEdgeOnFace(myE, myF, myContext);
++ if (iErr) {
++ BOPTools_AlgoTools2D::BuildPCurveForEdgeOnFace(myE, myF, myContext);
++ }
++ //
++ if (myFlag) {
++ UpdateVertices(myE, myF);
++ }
+ }
+- //
+- if (myFlag) {
+- UpdateVertices(myE, myF);
++ catch (Standard_Failure)
++ {
++ AddError(new BOPAlgo_AlertBuildingPCurveFailed(TopoDS_Shape()));
+ }
+ }
+ //
+@@ -676,6 +686,20 @@ void BOPAlgo_PaveFiller::MakePCurves()
+ //======================================================
+ BOPAlgo_MPCCnt::Perform(myRunParallel, aVMPC, myContext);
+ //======================================================
++
++ // Add warnings of the failed projections
++ Standard_Integer aNb = aVMPC.Extent();
++ for (i = 0; i < aNb; ++i)
++ {
++ if (aVMPC(i).HasErrors())
++ {
++ TopoDS_Compound aWC;
++ BRep_Builder().MakeCompound(aWC);
++ BRep_Builder().Add(aWC, aVMPC(i).Edge());
++ BRep_Builder().Add(aWC, aVMPC(i).Face());
++ AddWarning(new BOPAlgo_AlertBuildingPCurveFailed(aWC));
++ }
++ }
+ }
+ //=======================================================================
+ //function : UpdateVertices
+diff --git a/src/BOPAlgo/BOPAlgo_PaveFiller_8.cxx b/src/BOPAlgo/BOPAlgo_PaveFiller_8.cxx
+index 495c640..08f515a 100644
+--- a/src/BOPAlgo/BOPAlgo_PaveFiller_8.cxx
++++ b/src/BOPAlgo/BOPAlgo_PaveFiller_8.cxx
+@@ -32,6 +32,7 @@
+ #include <Geom2d_Line.hxx>
+ #include <Geom2d_TrimmedCurve.hxx>
+ #include <Geom2dAdaptor_Curve.hxx>
++#include <Geom2dAPI_ProjectPointOnCurve.hxx>
+ #include <Geom2dInt_GInter.hxx>
+ #include <gp_Lin2d.hxx>
+ #include <gp_Pnt.hxx>
+@@ -52,6 +53,11 @@ static
+ const Standard_Real aP2,
+ TopoDS_Edge& aNewEdge);
+
++static
++ Standard_Boolean AddSplitPoint(const Handle(BOPDS_PaveBlock)& thePBD,
++ const BOPDS_Pave& thePave,
++ const Standard_Real theTol);
++
+ //=======================================================================
+ //function : ProcessDE
+ //purpose :
+@@ -304,25 +310,30 @@ void BOPAlgo_PaveFiller::ProcessDE()
+ }
+ // Intersection
+ Geom2dInt_GInter aGInter(aGAC1, aGAC2, aTolInt, aTolInt);
+- if (!aGInter.IsDone()) {
+- continue;
+- }
+- //
+- // Analyze intersection points
+- Standard_Integer i, aNbPoints = aGInter.NbPoints();
+- for (i = 1; i <= aNbPoints; ++i) {
+- Standard_Real aX = aGInter.Point(i).ParamOnFirst();
+- if (aX - aTD1 < aTolCmp || aTD2 - aX < aTolCmp) {
+- continue;
++ if (aGInter.IsDone() && aGInter.NbPoints())
++ {
++ // Analyze intersection points
++ Standard_Integer i, aNbPoints = aGInter.NbPoints();
++ for (i = 1; i <= aNbPoints; ++i) {
++ Standard_Real aX = aGInter.Point(i).ParamOnFirst();
++ aPave.SetParameter(aX);
++ AddSplitPoint(aPBD, aPave, aTolCmp);
+ }
+- //
+- Standard_Integer anInd;
+- if (aPBD->ContainsParameter(aX, aTolCmp, anInd)) {
+- continue;
++ }
++ else
++ {
++ // If the intersection did not succeed, try the projection of the end point
++ // of the curve corresponding to the vertex of degenerated edge
++ Standard_Real aT = (nVD == aPB->Pave1().Index() ?
++ aPB->Pave1().Parameter() : aPB->Pave2().Parameter());
++ gp_Pnt2d aP2d = aC2D->Value(aT);
++ Geom2dAPI_ProjectPointOnCurve aProj2d(aP2d, aC2DDE, aTD1, aTD2);
++ if (aProj2d.NbPoints())
++ {
++ Standard_Real aX = aProj2d.LowerDistanceParameter();
++ aPave.SetParameter(aX);
++ AddSplitPoint(aPBD, aPave, aTolCmp);
+ }
+- //
+- aPave.SetParameter(aX);
+- aPBD->AppendExtPave1(aPave);
+ }
+ }
+ }
+@@ -354,3 +365,34 @@ void BOPAlgo_PaveFiller::ProcessDE()
+ BB.UpdateEdge(E, aTol);
+ aNewEdge=E;
+ }
++
++//=======================================================================
++// function: AddSplitPoint
++// purpose: Validates the point represented by the pave <thePave>
++// for the Pave Block <thePBD>.
++// In case the point passes the checks it is added as an
++// Extra Pave to the Pave Block for further splitting of the latter.
++// Returns TRUE if the point is added, otherwise returns FALSE.
++//=======================================================================
++Standard_Boolean AddSplitPoint(const Handle(BOPDS_PaveBlock)& thePBD,
++ const BOPDS_Pave& thePave,
++ const Standard_Real theTol)
++{
++ Standard_Real aTD1, aTD2;
++ thePBD->Range(aTD1, aTD2);
++
++ Standard_Real aT = thePave.Parameter();
++ // Check that the parameter is inside the Pave Block
++ if (aT - aTD1 < theTol || aTD2 - aT < theTol)
++ return Standard_False;
++
++ // Check that the pave block does not contain the same parameter
++ Standard_Integer anInd;
++ if (thePBD->ContainsParameter(aT, theTol, anInd))
++ return Standard_False;
++
++ // Add the point as an Extra pave to the Pave Block for further
++ // splitting of the latter
++ thePBD->AppendExtPave1(thePave);
++ return Standard_True;
++}
+diff --git a/src/BOPTest/BOPTest_CheckCommands.cxx b/src/BOPTest/BOPTest_CheckCommands.cxx
+index 618e86c..77d5cd2 100644
+--- a/src/BOPTest/BOPTest_CheckCommands.cxx
++++ b/src/BOPTest/BOPTest_CheckCommands.cxx
+@@ -235,6 +235,8 @@ Standard_Integer bopcheck (Draw_Interpretor& di,
+ //
+ aTimer.Stop();
+ //
++ BOPTest::ReportAlerts(aChecker);
++ //
+ iErr=aChecker.HasErrors();
+ //
+ const BOPDS_DS& aDS=*(aChecker.PDS());
+diff --git a/src/IntWalk/IntWalk_PWalking.cxx b/src/IntWalk/IntWalk_PWalking.cxx
+index 54c42a1..eed1c63 100644
+--- a/src/IntWalk/IntWalk_PWalking.cxx
++++ b/src/IntWalk/IntWalk_PWalking.cxx
+@@ -159,6 +159,35 @@ static void IsParallel(const Handle(IntSurf_LineOn2S)& theLine,
+ theIsUparallel = ((aVmax - aVmin) < theToler);
+ }
+
++//=======================================================================
++//function : AdjustToDomain
++//purpose : Returns TRUE if theP has been changed (i.e. initial value
++// was out of the domain)
++//=======================================================================
++static Standard_Boolean AdjustToDomain(const Standard_Integer theNbElem,
++ Standard_Real* theParam,
++ const Standard_Real* const theLowBorder,
++ const Standard_Real* const theUppBorder)
++{
++ Standard_Boolean aRetVal = Standard_False;
++ for (Standard_Integer i = 0; i < theNbElem; i++)
++ {
++ if ((theParam[i] - theLowBorder[i]) < -Precision::PConfusion())
++ {
++ theParam[i] = theLowBorder[i];
++ aRetVal = Standard_True;
++ }
++
++ if ((theParam[i] - theUppBorder[i]) > Precision::PConfusion())
++ {
++ theParam[i] = theUppBorder[i];
++ aRetVal = Standard_True;
++ }
++ }
++
++ return aRetVal;
++}
++
+ //==================================================================================
+ // function : IntWalk_PWalking::IntWalk_PWalking
+ // purpose :
+@@ -2247,7 +2276,19 @@ Standard_Boolean IntWalk_PWalking::HandleSingleSingularPoint(const Handle(Adapto
+ continue;
+
+ anInt.Point().Parameters(thePnt(1), thePnt(2), thePnt(3), thePnt(4));
+- return Standard_True;
++
++ Standard_Boolean isInDomain = Standard_True;
++ for (Standard_Integer j = 1; isInDomain && (j <= 4); ++j)
++ {
++ if ((thePnt(j) - aLowBorder[j - 1] + Precision::PConfusion())*
++ (thePnt(j) - aUppBorder[j - 1] - Precision::PConfusion()) > 0.0)
++ {
++ isInDomain = Standard_False;
++ }
++ }
++
++ if (isInDomain)
++ return Standard_True;
+ }
+ }
+
+@@ -2259,16 +2300,26 @@ Standard_Boolean IntWalk_PWalking::HandleSingleSingularPoint(const Handle(Adapto
+ //purpose :
+ //=======================================================================
+ Standard_Boolean IntWalk_PWalking::
+-SeekPointOnBoundary(const Handle(Adaptor3d_HSurface)& theASurf1,
+- const Handle(Adaptor3d_HSurface)& theASurf2,
+- const Standard_Real theU1,
+- const Standard_Real theV1,
+- const Standard_Real theU2,
+- const Standard_Real theV2,
+- const Standard_Boolean isTheFirst)
++ SeekPointOnBoundary(const Handle(Adaptor3d_HSurface)& theASurf1,
++ const Handle(Adaptor3d_HSurface)& theASurf2,
++ const Standard_Real theU1,
++ const Standard_Real theV1,
++ const Standard_Real theU2,
++ const Standard_Real theV2,
++ const Standard_Boolean isTheFirst)
+ {
+ Standard_Boolean isOK = Standard_False;
+
++ // u1, v1, u2, v2 order is used.
++ const Standard_Real aLowBorder[4] = {theASurf1->FirstUParameter(),
++ theASurf1->FirstVParameter(),
++ theASurf2->FirstUParameter(),
++ theASurf2->FirstVParameter()};
++ const Standard_Real aUppBorder[4] = {theASurf1->LastUParameter(),
++ theASurf1->LastVParameter(),
++ theASurf2->LastUParameter(),
++ theASurf2->LastVParameter()};
++
+ // Tune solution tolerance according with object size.
+ const Standard_Real aRes1 = Max(Precision::PConfusion() / theASurf1->UResolution(1.0),
+ Precision::PConfusion() / theASurf1->VResolution(1.0));
+@@ -2288,21 +2339,26 @@ SeekPointOnBoundary(const Handle(Adaptor3d_HSurface)& theASurf1,
+ {
+ aNbIter--;
+ aStatus = DistanceMinimizeByGradient(theASurf1, theASurf2, aPnt);
+- if(aStatus)
++ if (aStatus && !AdjustToDomain(4, &aPnt(1), &aLowBorder[0], &aUppBorder[0]))
+ break;
+
+- aStatus = DistanceMinimizeByExtrema(theASurf1, theASurf2->Value(aPnt(3), aPnt(4)), aPnt(1), aPnt(2));
+- if(aStatus)
++ aStatus = DistanceMinimizeByExtrema(theASurf1, theASurf2->Value(aPnt(3), aPnt(4)),
++ aPnt(1), aPnt(2));
++ if (aStatus && !AdjustToDomain(2, &aPnt(1), &aLowBorder[0], &aUppBorder[0]))
+ break;
+
+- aStatus = DistanceMinimizeByExtrema(theASurf2, theASurf1->Value(aPnt(1), aPnt(2)), aPnt(3), aPnt(4));
+- if(aStatus)
++ aStatus = DistanceMinimizeByExtrema(theASurf2, theASurf1->Value(aPnt(1), aPnt(2)),
++ aPnt(3), aPnt(4));
++ if (aStatus && !AdjustToDomain(2, &aPnt(3), &aLowBorder[2], &aUppBorder[2]))
+ break;
+ }
+ while(!aStatus && (aNbIter > 0));
+
+ // Handle singular points.
+- Standard_Boolean aSingularStatus = HandleSingleSingularPoint(theASurf1, theASurf2, aTol, aSingularPnt);
++ Standard_Boolean aSingularStatus = HandleSingleSingularPoint(theASurf1,
++ theASurf2,
++ aTol,
++ aSingularPnt);
+ if (aSingularStatus)
+ aPnt = aSingularPnt;
+
+diff --git a/tests/bugs/modalg_7/bug25879 b/tests/bugs/modalg_7/bug25879
+index bb45244..e344c39 100755
+--- a/tests/bugs/modalg_7/bug25879
++++ b/tests/bugs/modalg_7/bug25879
+@@ -13,7 +13,8 @@ explode Box E
+
+ blend Fillet Box 1 Box_1 1 Box_2 1 Box_3 1 Box_4 1 Box_5 1 Box_6 1 Box_7 1 Box_8 1 Box_9 1 Box_10 1 Box_11 1 Box_12
+
+-if { [regexp "There were errors during the operation, so the list may be incomplete" [bopcheck Fillet]] == 1 } {
++set bug_info [string trim [bopcheck Fillet]]
++if {$bug_info != "This shape seems to be OK."} {
+ puts "Error : result of blend fails the bopcheck"
+ }
+
+diff --git a/tests/bugs/modalg_7/bug29073 b/tests/bugs/modalg_7/bug29073
+new file mode 100644
+index 0000000..e13beca
+--- /dev/null
++++ b/tests/bugs/modalg_7/bug29073
+@@ -0,0 +1,34 @@
++puts "======="
++puts "0029073"
++puts "======="
++puts ""
++##################################################
++# Regression: General Cut produces invalid shape
++##################################################
++
++brestore [locate_data_file bug29073_M6.brep] b1
++brestore [locate_data_file bug29073_Shell.brep] b2
++
++bclearobjects
++bcleartools
++baddobjects b1
++baddtools b2
++bfillds
++
++# check the result of SECTION
++bbop rsec 4
++checknbshapes rsec -edge 1 -vertex 2
++
++# check the result of GF
++bbuild rgf
++checkshape rgf
++checkprops rgf -s 163.708 -v 115.912
++checknbshapes rgf -wire 25 -face 24 -shell 3 -solid 1
++
++# check the CUT
++bbop result 3
++checkshape result
++checkprops result -s 0.000713987
++checknbshapes result -wire 1 -face 1
++
++checkview -display result -2d -path ${imagedir}/${test_image}.png
+diff --git a/tests/bugs/modalg_7/bug29099 b/tests/bugs/modalg_7/bug29099
+new file mode 100644
+index 0000000..f4bbf91
+--- /dev/null
++++ b/tests/bugs/modalg_7/bug29099
+@@ -0,0 +1,23 @@
++puts "======="
++puts "0029099"
++puts "======="
++puts ""
++##################################################
++# Extra shapes in result of General Cut (box by ellipsoid)
++##################################################
++
++brestore [locate_data_file bug29099_Box.brep] b1
++brestore [locate_data_file bug29099_Rotation.brep] b2
++
++bclearobjects
++bcleartools
++baddobjects b1
++baddtools b2
++bfillds
++bbuild result
++
++checkshape result
++checknbshapes result -wire 11 -face 10 -shell 3 -solid 3
++checkprops result -s 12651.3 -v 52187.5
++
++checkview -display result -2d -path ${imagedir}/${test_image}.png
+\ No newline at end of file
+diff --git a/tests/bugs/modalg_7/bug29103 b/tests/bugs/modalg_7/bug29103
+new file mode 100644
+index 0000000..33bc06c
+--- /dev/null
++++ b/tests/bugs/modalg_7/bug29103
+@@ -0,0 +1,56 @@
++puts "========"
++puts "OCC29103"
++puts "========"
++puts ""
++#################################################
++# No intersection curve between faces if starting points are given
++#################################################
++
++set MaxTolReached 2.0e-7
++set GoodNbCurv 1
++set ExpLength 0.074141742883251954
++
++restore [locate_data_file bug29073_M6.brep] a
++restore [locate_data_file bug29073_Shell.brep] b
++explode a f
++explode b f
++
++don b_2
++axo
++fit
++disp a_6
++
++set log1 [bopcurves a_6 b_2 -2d]
++
++checkview -screenshot -2d -path ${imagedir}/${test_image}_1.png
++checklength c_1 -l $ExpLength
++
++don b_2
++axo
++fit
++disp a_6
++
++set log2 [bopcurves a_6 b_2 -2d -p -0.55478319275098653 1.2919191091235780 0.80333089657224976 0.67079577554162440 -p -0.62451407353846222 1.2667484772947102 0.82894736842100003 0.70523311453721027]
++
++checkview -screenshot -2d -path ${imagedir}/${test_image}_2.png
++checklength c_1 -l $ExpLength
++
++regexp {Tolerance Reached=+([-0-9.+eE]+)\n+([-0-9.+eE]+)} ${log1} full Toler1 NbCurv1
++regexp {Tolerance Reached=+([-0-9.+eE]+)\n+([-0-9.+eE]+)} ${log2} full Toler2 NbCurv2
++
++if {$Toler1 > $MaxTolReached} {
++ puts "Error: Big tolerance is returned by intersector w/o start points"
++}
++
++if {$Toler2 > $MaxTolReached} {
++ puts "Error: Big tolerance is returned by intersector with start points"
++}
++
++if {$NbCurv1 != $GoodNbCurv} {
++ puts "Error: Please check NbCurves for intersector w/o start points"
++}
++
++if {$NbCurv2 != $GoodNbCurv} {
++ puts "Error: Please check NbCurves for intersector with start points"
++}
++
+diff --git a/tests/bugs/moddata_3/bug25693_1 b/tests/bugs/moddata_3/bug25693_1
+index de7953d..86d1aeb 100755
+--- a/tests/bugs/moddata_3/bug25693_1
++++ b/tests/bugs/moddata_3/bug25693_1
+@@ -10,7 +10,8 @@ puts ""
+
+ restore [locate_data_file bug25693_path3035.brep] result
+
+-if { [regexp "There were errors during the operation, so the list may be incomplete" [bopcheck result]] == 1 } {
++set bug_info [string trim [bopcheck result]]
++if {$bug_info != "This shape seems to be OK."} {
+ puts "Error : Wire of BSplines fails bopcheck"
+ }
+
+diff --git a/tests/bugs/moddata_3/bug25693_2 b/tests/bugs/moddata_3/bug25693_2
+index 6b3bfb1..cfc7a0e 100755
+--- a/tests/bugs/moddata_3/bug25693_2
++++ b/tests/bugs/moddata_3/bug25693_2
+@@ -12,11 +12,13 @@ restore [locate_data_file bug25693_path3039.brep] path3039
+
+ prism Extrude_path3039 path3039 0 0 50
+
+-if { [regexp "There were errors during the operation, so the list may be incomplete" [bopcheck path3039]] == 1 } {
++set log1 [string trim [bopcheck path3039]]
++if {$log1 != "This shape seems to be OK."} {
+ puts "Error : bad shape"
+ }
+
+-if { [regexp "There were errors during the operation, so the list may be incomplete" [bopcheck Extrude_path3039]] == 1 } {
++set log2 [string trim [bopcheck Extrude_path3039]]
++if {$log2 != "This shape seems to be OK."} {
+ puts "Error : Wire of BSplines fails bopcheck"
+ }
+
