diff --git a/libsrc/include/nginterface_v2.hpp b/libsrc/include/nginterface_v2.hpp
index d2407ea8..6dd9ff07 100644
--- a/libsrc/include/nginterface_v2.hpp
+++ b/libsrc/include/nginterface_v2.hpp
@@ -271,8 +271,8 @@ namespace netgen
 
     // returns domain numbers of domains next to boundary bnr -> (domin, domout)
     // 3D only
-    // std::pair<int,int> GetBoundaryNeighbouringDomains (int bnr);
-
+    std::pair<int,int> GetBoundaryNeighbouringDomains (int bnr);
+    
     void Refine (NG_REFINEMENT_TYPE reftype,
                  void (*taskmanager)(function<void(int,int)>) = &DummyTaskManager2);
 
diff --git a/libsrc/interface/nginterface_v2.cpp b/libsrc/interface/nginterface_v2.cpp
index d7548127..509d1274 100644
--- a/libsrc/interface/nginterface_v2.cpp
+++ b/libsrc/interface/nginterface_v2.cpp
@@ -141,6 +141,16 @@ namespace netgen
     return -1;
   }
 
+  std::pair<int,int> Ngx_Mesh :: GetBoundaryNeighbouringDomains (int bnr)
+  {
+    if ( mesh->GetDimension() == 3 )
+      return std::pair<int,int>(mesh->GetFaceDescriptor(bnr+1).DomainIn(),
+				mesh->GetFaceDescriptor(bnr+1).DomainOut());
+    else
+      return std::pair<int,int>(-1,-1);
+  }
+
+
   /*
   Ng_Point Ngx_Mesh :: GetPoint (int nr) const
   {