diff --git a/EXE_GeoSnap.cpp b/EXE_GeoSnap.cpp
index 53633d5..37a3456 100644
--- a/EXE_GeoSnap.cpp
+++ b/EXE_GeoSnap.cpp
@@ -27,6 +27,7 @@
 #include "/EgtDev/Include/EgkSurf.h"
 #include "/EgtDev/Include/EgkSurfFlatRegion.h"
 #include "/EgtDev/Include/EgkSurfTriMesh.h"
+#include "/EgtDev/Include/EGkSurfLocal.h"
 #include "/EgtDev/Include/EgkVolZmap.h"
 #include "/EgtDev/Include/EgkExtText.h"
 #include "/EgtDev/Include/EgkDistPointCurve.h"
@@ -966,6 +967,32 @@ ExeSurfFrChunkSimpleClassify( int nId1, int nChunk1, int nId2, int nChunk2)
    return nRes ;
 }
 
+//----------------------------------------------------------------------------
+bool
+ExeSurfFrTestExternal( int nId1, int nId2, double dMinDist)
+{
+   IGeomDB* pGeomDB = GetCurrGeomDB() ;
+   VERIFY_GEOMDB( pGeomDB, GDB_ID_NULL)
+  // recupero la prima superficie FlatRegion
+   ISurfFlatRegion* pSfr1 = GetSurfFlatRegion( pGeomDB->GetGeoObj( nId1)) ;
+   bool bOk = ( pSfr1 != nullptr) ;
+  // recupero il riferimento della superficie
+   Frame3d frSurf1 ;
+   bOk = bOk && pGeomDB->GetGlobFrame( nId1, frSurf1) ;
+  // recupero la seconda superficie FlatRegion in locale alla prima
+   SurfLocal Surf2Loc( pGeomDB, nId2, frSurf1) ;
+   const ISurfFlatRegion* pSfr2L = GetSurfFlatRegion( Surf2Loc) ;
+   bOk = bOk && ( pSfr2L != nullptr) ;
+  // se richiesta distanza di sicurezza, ne faccio l'offset
+   PtrOwner<ISurfFlatRegion> pSfr2LO( pSfr2L->Clone()) ;
+   bOk = bOk && ( ! IsNull( pSfr2LO)) ;
+   if ( bOk  &&  dMinDist > 10 * EPS_SMALL)
+      pSfr2LO->Offset( dMinDist, ICurve::OFF_FILLET) ;
+  // eseguo il test di intersezione tra le due superfici
+   bOk = bOk && ( pSfr1->GetChunkSimpleClassification( 0, *pSfr2LO, 0) == REGC_OUT) ;
+   return bOk ;
+}
+
 //----------------------------------------------------------------------------
 int
 ExeSurfTmFacetCount( int nId)
diff --git a/EgtExecutor.rc b/EgtExecutor.rc
index 642acef..380b9e3 100644
Binary files a/EgtExecutor.rc and b/EgtExecutor.rc differ
diff --git a/LUA_GeoSnap.cpp b/LUA_GeoSnap.cpp
index f470135..0a59f17 100644
--- a/LUA_GeoSnap.cpp
+++ b/LUA_GeoSnap.cpp
@@ -686,6 +686,24 @@ LuaSurfFrChunkSimpleClassify( lua_State* L)
    return 1 ;
 }
 
+//----------------------------------------------------------------------------
+static int
+LuaSurfFrTestExternal( lua_State* L)
+{
+  // 2 o 3 parametri : Id1, Id2 [, dMinDist]
+   int nId1 ;
+   LuaCheckParam( L, 1, nId1)
+   int nId2 ;
+   LuaCheckParam( L, 2, nId2)
+   double dMinDist = 0 ;
+   LuaGetParam( L, 3, dMinDist) ;
+   LuaClearStack( L) ;
+  // verifico se le due regioni sono esterne con distanza superiore al minimo
+   bool bOk = ExeSurfFrTestExternal( nId1, nId2, dMinDist) ;
+   LuaSetParam( L, bOk) ;
+   return 1 ;
+}
+
 //----------------------------------------------------------------------------
 static int
 LuaSurfTmFacetCount( lua_State* L)
@@ -1042,6 +1060,7 @@ LuaInstallGeoSnap( LuaMgr& luaMgr)
    bOk = bOk && luaMgr.RegisterFunction( "EgtSurfFrGrossArea", LuaSurfFrGrossArea) ;
    bOk = bOk && luaMgr.RegisterFunction( "EgtSurfFrChunkCount", LuaSurfFrChunkCount) ;
    bOk = bOk && luaMgr.RegisterFunction( "EgtSurfFrChunkSimpleClassify", LuaSurfFrChunkSimpleClassify) ;
+   bOk = bOk && luaMgr.RegisterFunction( "EgtSurfFrTestExternal", LuaSurfFrTestExternal) ;
    bOk = bOk && luaMgr.RegisterFunction( "EgtSurfTmFacetCount", LuaSurfTmFacetCount) ;
    bOk = bOk && luaMgr.RegisterFunction( "EgtSurfTmFacetAdjacencies", LuaSurfTmFacetAdjacencies) ;
    bOk = bOk && luaMgr.RegisterFunction( "EgtSurfTmFacetNearestEndPoint", LuaSurfTmFacetNearestEndPoint) ;