diff --git a/libsrc/csg/identify.cpp b/libsrc/csg/identify.cpp
index 8e5b8923..95a6bb13 100644
--- a/libsrc/csg/identify.cpp
+++ b/libsrc/csg/identify.cpp
@@ -1274,6 +1274,7 @@ BuildSurfaceElements (Array<Segment> & segs,
                 if (nst1 * dvec < 0) continue;
                 
 		Element2d el(s1[0], s1[1], s2[0], s2[1]);
+                el.SetIndex(s1.si);
 
 		Vec<3> n = Cross (mesh[el[1]] - mesh[el[0]],
 				  mesh[el[3]] - mesh[el[0]]);
diff --git a/libsrc/meshing/meshclass.cpp b/libsrc/meshing/meshclass.cpp
index bc79a563..13177eba 100644
--- a/libsrc/meshing/meshclass.cpp
+++ b/libsrc/meshing/meshclass.cpp
@@ -314,7 +314,7 @@ namespace netgen
     SurfaceElementIndex si = surfelements.Size();
     surfelements.Append (el); 
 
-    if (el.index > facedecoding.Size())
+    if (el.index<=0 || el.index > facedecoding.Size())
       cerr << "has no facedecoding: fd.size = " << facedecoding.Size() << ", ind = " << el.index << endl;
 
     surfelements.Last().next = facedecoding[el.index-1].firstelement;