0028491: Incomplete section curve

The main idea of the fix is to forbid check if intersection curve lies in the some face (with input tolerance) if we have 2D-intersection curve on this face (we consider that necessary tolerance has been computed in intersection algorithm honestly). If we do not have 2D-curve on this face then we need check as before.

New algorithm is implemented in IntTools_Context::IsValidBlockForFaces(...) method.

------
src\Extrema\Extrema_GenExtPS.cxx
No principled changes have been made.

src/Extrema/Extrema_GenExtPS.cxx

@@ -896,17 +896,31 @@ void Extrema_GenExtPS::Perform(const gp_Pnt& P)
     {
       Standard_Real Dist;
 
-      for (NoU = 1; NoU <= myusample; NoU++) {
-        for (NoV = 1; NoV <= myvsample; NoV++) {
-          Dist = myPoints->Value(NoU, NoV).GetSqrDistance();
-          if ((myPoints->Value(NoU-1,NoV-1).GetSqrDistance() <= Dist) &&
-              (myPoints->Value(NoU-1,NoV  ).GetSqrDistance() <= Dist) &&
-              (myPoints->Value(NoU-1,NoV+1).GetSqrDistance() <= Dist) &&
-              (myPoints->Value(NoU  ,NoV-1).GetSqrDistance() <= Dist) &&
-              (myPoints->Value(NoU  ,NoV+1).GetSqrDistance() <= Dist) &&
-              (myPoints->Value(NoU+1,NoV-1).GetSqrDistance() <= Dist) &&
-              (myPoints->Value(NoU+1,NoV  ).GetSqrDistance() <= Dist) &&
-              (myPoints->Value(NoU+1,NoV+1).GetSqrDistance() <= Dist)) {
+      for (NoU = 1; NoU <= myusample; NoU++)
+      {
+        for (NoV = 1; NoV <= myvsample; NoV++)
+        {
+          const Extrema_POnSurfParams &aParamMain = myPoints->Value(NoU, NoV);
+          const Extrema_POnSurfParams &aParam1 = myPoints->Value(NoU - 1, NoV - 1);
+          const Extrema_POnSurfParams &aParam2 = myPoints->Value(NoU - 1, NoV);
+          const Extrema_POnSurfParams &aParam3 = myPoints->Value(NoU - 1, NoV + 1);
+          const Extrema_POnSurfParams &aParam4 = myPoints->Value(NoU, NoV - 1);
+          const Extrema_POnSurfParams &aParam5 = myPoints->Value(NoU, NoV + 1);
+          const Extrema_POnSurfParams &aParam6 = myPoints->Value(NoU + 1, NoV - 1);
+          const Extrema_POnSurfParams &aParam7 = myPoints->Value(NoU + 1, NoV);
+          const Extrema_POnSurfParams &aParam8 = myPoints->Value(NoU + 1, NoV + 1);
+
+          Dist = aParamMain.GetSqrDistance();
+
+          if ((aParam1.GetSqrDistance() <= Dist) &&
+              (aParam2.GetSqrDistance() <= Dist) &&
+              (aParam3.GetSqrDistance() <= Dist) &&
+              (aParam4.GetSqrDistance() <= Dist) &&
+              (aParam5.GetSqrDistance() <= Dist) &&
+              (aParam6.GetSqrDistance() <= Dist) &&
+              (aParam7.GetSqrDistance() <= Dist) &&
+              (aParam8.GetSqrDistance() <= Dist))
+          {
             // Find maximum.
             FindSolution(P, myPoints->Value(NoU, NoV));
           }

src/IntTools/IntTools_Context.cxx

@@ -803,41 +803,44 @@ Standard_Boolean IntTools_Context::IsValidBlockForFace
 //function : IsValidBlockForFaces
 //purpose  : 
 //=======================================================================
-Standard_Boolean IntTools_Context::IsValidBlockForFaces 
-  (const Standard_Real aT1,
-   const Standard_Real aT2,
-   const IntTools_Curve& aC, 
-   const TopoDS_Face& aF1,
-   const TopoDS_Face& aF2,
-   const Standard_Real aTol) 
+Standard_Boolean IntTools_Context::IsValidBlockForFaces(const Standard_Real theT1,
+                                                        const Standard_Real theT2,
+                                                        const IntTools_Curve& theC, 
+                                                        const TopoDS_Face& theF1,
+                                                        const TopoDS_Face& theF2,
+                                                        const Standard_Real theTol) 
 {
-  Standard_Boolean bFlag1, bFlag2;
-  //
-  Handle(Geom2d_Curve) aPC1 = aC.FirstCurve2d();
-  Handle(Geom2d_Curve) aPC2 = aC.SecondCurve2d();
-  if( !aPC1.IsNull() && !aPC2.IsNull() ) {
-    Standard_Real aMidPar = IntTools_Tools::IntermediatePoint(aT1, aT2);
-    gp_Pnt2d aPnt2D;
+  const Standard_Integer aNbElem = 2;
+  const Handle(Geom2d_Curve) &aPC1 = theC.FirstCurve2d();
+  const Handle(Geom2d_Curve) &aPC2 = theC.SecondCurve2d();
+  const Handle(Geom_Curve)   &aC3D = theC.Curve();
+  
+  const Handle(Geom2d_Curve)* anArrPC[aNbElem] = { &aPC1, &aPC2 };
+  const TopoDS_Face* anArrF[aNbElem] = { &theF1, &theF2 };
 
+  const Standard_Real aMidPar = IntTools_Tools::IntermediatePoint(theT1, theT2);
+  const gp_Pnt aP(aC3D->Value(aMidPar));
 
-    aPC1->D0(aMidPar, aPnt2D);
-    bFlag1 = IsPointInOnFace(aF1, aPnt2D);
+  Standard_Boolean bFlag = Standard_True;  
+  gp_Pnt2d aPnt2D;  
 
-    if( !bFlag1 )
-      return bFlag1;
+  for (Standard_Integer i = 0; (i < 2) && bFlag; ++i)
+  {
+    const Handle(Geom2d_Curve) &aPC = *anArrPC[i];
+    const TopoDS_Face &aF           = *anArrF[i];
 
-    aPC2->D0(aMidPar, aPnt2D);
-    bFlag2 = IsPointInOnFace(aF2, aPnt2D);
-    return bFlag2;
+    if (!aPC.IsNull())
+    {
+      aPC->D0(aMidPar, aPnt2D);
+      bFlag = IsPointInOnFace(aF, aPnt2D);
+    }
+    else
+    {
+      bFlag = IsValidPointForFace(aP, aF, theTol);
+    }
   }
-  //
 
-  bFlag1=IsValidBlockForFace (aT1, aT2, aC, aF1, aTol);
-  if (!bFlag1) {
-    return bFlag1;
-  }
-  bFlag2=IsValidBlockForFace (aT1, aT2, aC, aF2, aTol);
-  return bFlag2;
+  return bFlag;
 }
 //=======================================================================
 //function : IsVertexOnLine

tests/bugs/modalg_6/bug24094

@@ -0,0 +1,24 @@
+puts "========"
+puts "OCC24094"
+puts "========"
+puts ""
+##########################################
+## Issure by option of BRepAlgoAPI_Section
+##########################################
+
+
+restore [locate_data_file bug24094_face.brep] a
+plane p 183.6 0 0 1 0 0 0 1 0
+mkface f p
+
+bsection r1 a f
+bsection r2 a f -na
+bsection r3 a f -n2d2
+bsection r4 a f -n2d
+bsection r5 a f -n2d -na
+
+checknbshapes r1 -vertex 2 -edge 1 -t
+checknbshapes r2 -vertex 2 -edge 1 -t
+checknbshapes r3 -vertex 2 -edge 1 -t
+checknbshapes r4 -vertex 2 -edge 1 -t
+checknbshapes r5 -vertex 2 -edge 1 -t

tests/bugs/modalg_6/bug28491

@@ -0,0 +1,26 @@
+puts "========"
+puts "OCC28491"
+puts "========"
+puts ""
+##########################################
+## Incomplete section curve
+##########################################
+
+set GoodLength 4.617
+
+restore [locate_data_file bug28491_H0.brep] h0
+restore [locate_data_file bug28491_Prism.brep] s1
+explode h0 f
+
+bsection r1 h0_57 s1
+bsection result h0_57 s1 -n2d2
+
+checkprops r1 -l $GoodLength
+checkprops result -l $GoodLength
+
+smallview
+don h0_57
+fit
+display result s1
+
+checkview -screenshot -2d -path ${imagedir}/${test_image}.png