From 3e9eba7906cd6d95ed9a6ec10706763b0d85d054 Mon Sep 17 00:00:00 2001
From: Matthias Hochsteger <mhochsteger@cerbsim.com>
Date: Mon, 5 Jun 2023 11:24:52 +0200
Subject: [PATCH] OCC - Handle internal (forward+reversed) edges correctly

---
 libsrc/occ/occ_face.cpp | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/libsrc/occ/occ_face.cpp b/libsrc/occ/occ_face.cpp
index 2e60469a..a092a3a0 100644
--- a/libsrc/occ/occ_face.cpp
+++ b/libsrc/occ/occ_face.cpp
@@ -63,7 +63,7 @@ namespace netgen
             auto & orientation = edge_orientation[edgenr];
             double s0, s1;
             auto cof = BRep_Tool::CurveOnSurface (edge, face, s0, s1);
-            if(edge.Orientation() == TopAbs_FORWARD)
+            if(edge.Orientation() == TopAbs_FORWARD || edge.Orientation() == TopAbs_INTERNAL)
             {
                 curve_on_face[FORWARD][edgenr] = cof;
                 orientation += FORWARD;
@@ -75,6 +75,15 @@ namespace netgen
                 orientation += REVERSED;
                 edge_on_face[REVERSED][edgenr] = edge;
             }
+            if(edge.Orientation() == TopAbs_INTERNAL)
+            {
+              // add reversed edge
+              auto r_edge = TopoDS::Edge(edge.Reversed());
+              auto cof = BRep_Tool::CurveOnSurface (r_edge, face, s0, s1);
+              curve_on_face[REVERSED][edgenr] = cof;
+              orientation += REVERSED;
+              edge_on_face[REVERSED][edgenr] = r_edge;
+            }
 
             if(orientation > BOTH)
                 throw Exception("have edge more than twice in face " + ToString(nr) + " " + properties.GetName() + ", orientation: " + ToString(orientation));