0020676: EDF 1212 GEOM: Partition operation creates vertices which causes mesh computation to fail with netgen

* Fix for internal edges

src/NETGENPlugin/NETGENPlugin_NETGEN_2D_ONLY.cxx

@@ -209,6 +209,7 @@ static TError AddSegmentsToMesh(netgen::Mesh&                    ngMesh,
 
     int firstPointID = ngMesh.GetNP() + 1;
     int edgeID = 1, posID = -2;
+    bool isInternalEdge = false;
     for ( int i = 0; i < wire->NbSegments(); ++i ) // loop on segments
     {
       // Add the first point of a segment
@@ -257,6 +258,7 @@ static TError AddSegmentsToMesh(netgen::Mesh&                    ngMesh,
           const TopoDS_Edge& edge = wire->Edge( wire->EdgeIndex( normParam ));
           edgeID = geom.emap.FindIndex( edge );
           posID  = posShapeID;
+          isInternalEdge = ( edge.Orientation() == TopAbs_INTERNAL );
           if ( onVertex ) // param on curve is different on each of two edges
             seg.epgeominfo[ iEnd ].dist = helper.GetNodeU( edge, pnt.node );
         }
@@ -274,14 +276,41 @@ static TError AddSegmentsToMesh(netgen::Mesh&                    ngMesh,
 //            << "\tp1 param: " << seg.epgeominfo[ 1 ].dist << endl
 //            << "\tp1 uv: " << seg.epgeominfo[ 1 ].u <<", "<< seg.epgeominfo[ 1 ].v << endl
 //            << "\tp1 edge: " << seg.epgeominfo[ 1 ].edgenr << endl;
-    }
+
-    Segment& seg = ngMesh.LineSegment( ngMesh.GetNSeg() );
+      if ( isInternalEdge )
+      {
 #ifdef NETGEN_NEW
-    seg.pnums[1] = firstPointID;
+        swap (seg.pnums[0], seg.pnums[1]);
 #else
-    seg.p2 = firstPointID;
+        swap (seg.p1, seg.p2);
 #endif
-  }
+        swap( seg.epgeominfo[0], seg.epgeominfo[1] );
+        seg.edgenr = ngMesh.GetNSeg() + 1; // segment id
+        ngMesh.AddSegment (seg);
+      }
+    } // loop on segments on a wire
+
+    // close chain of segments
+    bool isClosedWire = ( wire->FirstVertex().IsSame( wire->LastVertex() ));
+    if ( isClosedWire )
+    {
+      Segment& seg = ngMesh.LineSegment( ngMesh.GetNSeg() );
+#ifdef NETGEN_NEW
+      seg.pnums[1] = firstPointID;
+#else
+      seg.p2 = firstPointID;
+#endif
+    }
+    else // INTERNAL wire (Issue 0020676)
+    {
+      const SMDS_MeshNode * n = uvPtVec.back().node;
+      nodeVec.push_back( n );
+
+      MeshPoint mp( Point<3> (n->X(), n->Y(), n->Z()) );
+      ngMesh.AddPoint ( mp, 1, EDGEPOINT );
+    }
+
+  } // loop on wires of a face
 
   ngMesh.CalcSurfacesOfNode();