From e28b8c6218617f6842d598917626427be468dd45 Mon Sep 17 00:00:00 2001
From: nbv <nbv@opencascade.com>
Date: Fri, 26 Oct 2018 11:37:00 +0300
Subject: [PATCH] 0029673: Exception while Face-Face intersection

If 2D-curves are requested in intersection result but they cannot be created (by some reason) then the full set of curves (3D and two 2D) is rejected from the intersection result.
---
 src/IntTools/IntTools_FaceFace.cxx |  9 ++++++++-
 tests/lowalgos/intss/bug29673      | 17 +++++++++++++++++
 2 files changed, 25 insertions(+), 1 deletion(-)
 create mode 100644 tests/lowalgos/intss/bug29673

diff --git a/src/IntTools/IntTools_FaceFace.cxx b/src/IntTools/IntTools_FaceFace.cxx
index c01f4e3236..23f5eb83e6 100644
--- a/src/IntTools/IntTools_FaceFace.cxx
+++ b/src/IntTools/IntTools_FaceFace.cxx
@@ -819,11 +819,14 @@ void IntTools_FaceFace::MakeCurve(const Standard_Integer Index,
           aCurve.SetTolerance(aTolC);
         }
         //
-        aCurve.SetCurve(new Geom_TrimmedCurve(newc, fprm, lprm));
         if(myApprox1) { 
           Handle (Geom2d_Curve) C2d;
           GeomInt_IntSS::BuildPCurves(fprm, lprm, Tolpc,
                 myHS1->ChangeSurface().Surface(), newc, C2d);
+
+          if (C2d.IsNull())
+            continue;
+
           aCurve.SetFirstCurve2d(new Geom2d_TrimmedCurve(C2d, fprm, lprm));
         }
         //
@@ -831,6 +834,10 @@ void IntTools_FaceFace::MakeCurve(const Standard_Integer Index,
           Handle (Geom2d_Curve) C2d;
           GeomInt_IntSS::BuildPCurves(fprm, lprm, Tolpc,
                     myHS2->ChangeSurface().Surface(), newc, C2d);
+
+          if (C2d.IsNull())
+            continue;
+
           aCurve.SetSecondCurve2d(new Geom2d_TrimmedCurve(C2d, fprm, lprm));
         }
         //
diff --git a/tests/lowalgos/intss/bug29673 b/tests/lowalgos/intss/bug29673
new file mode 100644
index 0000000000..5e76e10894
--- /dev/null
+++ b/tests/lowalgos/intss/bug29673
@@ -0,0 +1,17 @@
+puts "========"
+puts "0029673: Ex-ception while Face-Face intersection"
+puts "========"
+puts ""
+
+restore [locate_data_file bug29673_f1.brep] f1
+restore [locate_data_file bug29673_f2.brep] f2
+
+regexp {Tolerance Reached=+([-0-9.+eE]+)\n+([-0-9.+eE]+)} [bopcurves f1 f2 -2d] full Toler NbCurv
+
+if {$Toler > 1.0e-7} {
+  puts "Error: too big tolerance"
+}
+
+if {$NbCurv != 1} {
+  puts "Error: Please check NbCurves for intersector"
+}