diff --git a/EXE_GdbCreateVol.cpp b/EXE_GdbCreateVol.cpp
index 87a43c2..c596c11 100644
--- a/EXE_GdbCreateVol.cpp
+++ b/EXE_GdbCreateVol.cpp
@@ -152,7 +152,7 @@ ExeCreateVolZmapByRegionExtrusion( int nParentId, int nSfrId, double dDimZ, doub
 
 //-------------------------------------------------------------------------------
 int
-ExeCreateVolZmapFromSurfTm( int nParentId, int nStmId, double dPrec, bool bTriDex)
+ExeCreateVolZmapFromSurfTm( int nParentId, int nStmId, double dPrec, bool bTriDex, double dExtraBox)
 {
    IGeomDB* pGeomDB = GetCurrGeomDB() ;
    VERIFY_GEOMDB( pGeomDB, GDB_ID_NULL)
@@ -169,7 +169,7 @@ ExeCreateVolZmapFromSurfTm( int nParentId, int nStmId, double dPrec, bool bTriDe
   // creo lo Zmap nel suo riferimento intrinseco
    PtrOwner<IVolZmap> pVZM( CreateVolZmap()) ;
    bOk = bOk && ! IsNull( pVZM) ;
-   bOk = bOk && pVZM->CreateFromTriMesh( *pStm, dPrec, bTriDex) ;
+   bOk = bOk && pVZM->CreateFromTriMesh( *pStm, dPrec, bTriDex, dExtraBox) ;
   // lo porto nel riferimento di destinazione
    bOk = bOk && pVZM->LocToLoc( frStm, frDest) ;
   // inserisco lo Zmap nel DB
@@ -177,10 +177,11 @@ ExeCreateVolZmapFromSurfTm( int nParentId, int nStmId, double dPrec, bool bTriDe
    ExeSetModified() ;
   // se richiesto, salvo il comando Lua equivalente
    if ( IsCmdLog()) {
-      string sLua = "EgtVolZmapFromTriMesh(" + IdToString( nParentId) + "," +
-                                               ToString( nStmId) + "," +
-                                               ToString( dPrec) + "," +
-                                               ( bTriDex ? "true" : "false") + ")" +
+      string sLua = "EgtVolZmapFromSurfTm(" + IdToString( nParentId) + "," +
+                                              ToString( nStmId) + "," +
+                                              ToString( dPrec) + "," +
+                                              ( bTriDex ? "true" : "false") + "," +
+                                              ToString( dExtraBox) + ")" +
                     " -- Id=" + ToString( nNewId) ;
       LOG_INFO( GetCmdLogger(), sLua.c_str()) ;
    }
diff --git a/LUA_GdbCreateVol.cpp b/LUA_GdbCreateVol.cpp
index 494d4a6..6fe445e 100644
--- a/LUA_GdbCreateVol.cpp
+++ b/LUA_GdbCreateVol.cpp
@@ -121,7 +121,7 @@ LuaCreateVolZmapByRegionExtrusion( lua_State* L)
 static int
 LuaCreateVolZmapFromSurfTm( lua_State* L)
 {
-  // 3 o 4 parametri : ParentId, StmId, dPrec [, bTriDex]
+  // 3 o 4 o 5 parametri : ParentId, StmId, dPrec [, bTriDex] [, dExtraBox]
    int nParentId ;
    LuaCheckParam( L, 1, nParentId)
    int nStmId ;
@@ -129,10 +129,14 @@ LuaCreateVolZmapFromSurfTm( lua_State* L)
    double dPrec ;
    LuaCheckParam( L, 3, dPrec)
    bool bTriDex = true ;
-   LuaGetParam( L, 4, bTriDex) ;
+   double dExtraBox = 0 ;
+   if ( LuaGetParam( L, 4, bTriDex))
+      LuaGetParam( L, 5, dExtraBox) ;
+   else
+      LuaGetParam( L, 4, dExtraBox) ;
    LuaClearStack( L) ;
   // creo VZM da superficie trimesh 
-   int nId = ExeCreateVolZmapFromSurfTm( nParentId, nStmId, dPrec, bTriDex) ;
+   int nId = ExeCreateVolZmapFromSurfTm( nParentId, nStmId, dPrec, bTriDex, dExtraBox) ;
   // restituisco il risultato
    if ( nId != GDB_ID_NULL)
       LuaSetParam( L, nId) ;