diff --git a/EXE_GdbCreateVol.cpp b/EXE_GdbCreateVol.cpp
index 6ca6247..f639830 100644
--- a/EXE_GdbCreateVol.cpp
+++ b/EXE_GdbCreateVol.cpp
@@ -53,7 +53,50 @@ ExeCreateVolZmap( int nParentId, const Point3d& ptIni, double dDimX, double dDim
    ExeSetModified() ;
   // se richiesto, salvo il comando Lua equivalente
    if ( IsCmdLog()) {
-      string sLua = "EgtVolZmapBox(" + IdToString( nParentId) + ",{" +
+      string sLua = "EgtVolZmapEmpty(" + IdToString( nParentId) + ",{" +
+                                       ToString( ptIni) + "}," +
+                                       ToString( dDimX) + "," +
+                                       ToString( dDimY) + "," +
+                                       ToString( dDimZ) + "," +
+                                       ToString( dPrec) + "," +
+                                       ( bTriDex ? "true" : "false") + "," +
+                                       RefTypeToString( nRefType) + ")" +
+                    " -- Id=" + ToString( nNewId) ;
+      LOG_INFO( GetCmdLogger(), sLua.c_str()) ;
+   }
+  // restituisco l'identificativo della nuova entità
+   return nNewId ;
+}
+
+//-------------------------------------------------------------------------------
+int ExeCreateVolZmapEmpty( int nParentId, const Point3d& ptIni, double dDimX, double dDimY, double dDimZ,
+                           double dPrec, bool bTriDex, int nRefType)
+{
+   IGeomDB* pGeomDB = GetCurrGeomDB() ;
+   VERIFY_GEOMDB( pGeomDB, GDB_ID_NULL)
+   nParentId = AdjustId( nParentId) ;
+  // recupero il riferimento locale
+   Frame3d frLoc ;
+   bool bOk = pGeomDB->GetGroupGlobFrame( nParentId, frLoc) ;
+  // porto in locale i punti
+   Point3d ptIniL = GetPointLocal( pGeomDB, ptIni, nRefType, frLoc) ;
+   Point3d ptOnXL = GetPointLocal( pGeomDB, ptIni + X_AX, nRefType, frLoc) ;
+   Point3d ptOnYL = GetPointLocal( pGeomDB, ptIni + Y_AX, nRefType, frLoc) ;
+  // ne ricavo un riferimento intrinseco
+   Frame3d frBox ;
+   bOk = bOk && frBox.Set( ptIniL, ptOnXL, ptOnYL) ;
+  // creo lo Zmap nel suo riferimento intrinseco
+   PtrOwner<IVolZmap> pVZM( CreateVolZmap()) ;
+   bOk = bOk && ! IsNull( pVZM) ;
+   bOk = bOk && pVZM->CreateEmptyMap( ORIG, dDimX, dDimY, dDimZ, dPrec, bTriDex) ;
+  // lo porto nel riferimento locale
+   bOk = bOk && pVZM->ToGlob( frBox) ;
+  // inserisco lo Zmap nel DB
+   int nNewId = ( bOk ? pGeomDB->AddGeoObj( GDB_ID_NULL, nParentId, Release( pVZM)) : GDB_ID_NULL) ;
+   ExeSetModified() ;
+  // se richiesto, salvo il comando Lua equivalente
+   if ( IsCmdLog()) {
+      string sLua = "EgtVolZmapEmpty(" + IdToString( nParentId) + ",{" +
                                        ToString( ptIni) + "}," +
                                        ToString( dDimX) + "," +
                                        ToString( dDimY) + "," +
@@ -118,8 +161,8 @@ ExeCreateVolZmapFromSurfTm( int nParentId, int nStmId, double dPrec, bool bTriDe
    const ISurfTriMesh* pStm = GetSurfTriMesh( pGeomDB->GetGeoObj( nStmId)) ;
    bool bOk = ( pStm != nullptr) ;
   // recupero il riferimento della trimesh
-   Frame3d frStm ;
-   bOk = bOk && pGeomDB->GetGlobFrame( nStmId, frStm) ;
+   //Frame3d frStm ;
+   //bOk = bOk && pGeomDB->GetGlobFrame( nStmId, frStm) ;
   // recupero il riferimento del gruppo di destinazione
    Frame3d frDest ;
    bOk = bOk && pGeomDB->GetGroupGlobFrame( nParentId, frDest) ;
@@ -128,19 +171,61 @@ ExeCreateVolZmapFromSurfTm( int nParentId, int nStmId, double dPrec, bool bTriDe
    bOk = bOk && ! IsNull( pVZM) ;
    bOk = bOk && pVZM->CreateFromTriMesh( *pStm, dPrec, bTriDex) ;
   // lo porto nel riferimento di destinazione
-   bOk = bOk && pVZM->LocToLoc( frStm, frDest) ;
+   //bOk = bOk && pVZM->LocToLoc( frStm, frDest) ;
   // inserisco lo Zmap nel DB
    int nNewId = ( bOk ? pGeomDB->AddGeoObj( GDB_ID_NULL, nParentId, Release( pVZM)) : GDB_ID_NULL) ;
    ExeSetModified() ;
   // se richiesto, salvo il comando Lua equivalente
    if ( IsCmdLog()) {
-      string sLua = "EgtVolZmapFromTriMesh(" + IdToString( nParentId) + "," +
-                                               ToString( nStmId) + "," +
-                                               ToString( dPrec) + "," +
-                                               ( bTriDex ? "true" : "false") + ")" +
+      string sLua = "UpdateVolZmapByAddingSurfTm(" + IdToString( nParentId) + "," +
+                                                   IdToString( nStmId) + "," +
+                                                   ToString( nStmId) + "," +
+                                                   ToString( dPrec) + "," +
+                                                   ( bTriDex ? "true" : "false") + ")" +
                     " -- Id=" + ToString( nNewId) ;
       LOG_INFO( GetCmdLogger(), sLua.c_str()) ;
    }
   // restituisco l'identificativo della nuova entità
    return nNewId ;
 }
+
+//-------------------------------------------------------------------------------
+bool
+ExeUpdateVolZmapByAddingSurfTm( int nParentId, int nZmapId, int nStmId)
+{
+   IGeomDB* pGeomDB = GetCurrGeomDB() ;
+   VERIFY_GEOMDB( pGeomDB, GDB_ID_NULL)
+   nParentId = AdjustId( nParentId) ;
+  // recupero lo Zmap
+   IVolZmap* pVolZmap = GetVolZmap( pGeomDB->GetGeoObj( nZmapId)) ;
+   bool bOk = pVolZmap != nullptr ;
+  // recupero il riferimento dello Zmap
+   Frame3d frZmap ;
+   bOk = bOk && pGeomDB->GetGlobFrame( nZmapId, frZmap) ;
+  // recupero la trimesh
+   PtrOwner<ISurfTriMesh> pStm( CloneSurfTriMesh( pGeomDB->GetGeoObj( nStmId))) ;
+   bOk = bOk && ( pStm != nullptr) ;
+  // recupero il riferimento della trimesh
+   Frame3d frStm ;
+   bOk = bOk && pGeomDB->GetGlobFrame( nStmId, frStm) ;
+  // recupero il riferimento del gruppo di destinazione
+   Frame3d frDest ;
+   bOk = bOk && pGeomDB->GetGroupGlobFrame( nParentId, frDest) ;
+  // porto lo Zmap e la trimesh nel riferimento della destinazione
+   bOk = bOk && 
+         pVolZmap->LocToLoc( frZmap, frDest) &&
+         pStm->LocToLoc( frStm, frDest) ;
+  // aggiorno lo Zmap
+   bOk = bOk &&  pVolZmap->AddSrfTm( pStm) ;
+  // riporto lo Zmap nel frame originario
+   bOk = bOk &&  pVolZmap->LocToLoc( frDest, frStm) ;
+   ExeSetModified() ;
+  // se richiesto, salvo il comando Lua equivalente
+   if ( IsCmdLog()) {
+      string sLua = "EgtVolZmapFromTriMesh(" + IdToString( nParentId) + "," +
+                                               ToString( nStmId) + ")" ;
+      LOG_INFO( GetCmdLogger(), sLua.c_str()) ;
+   }
+  // restituisco l'identificativo della nuova entità
+   return bOk ;
+}
diff --git a/LUA_GdbCreateVol.cpp b/LUA_GdbCreateVol.cpp
index 2e2e1fc..86c378d 100644
--- a/LUA_GdbCreateVol.cpp
+++ b/LUA_GdbCreateVol.cpp
@@ -54,6 +54,40 @@ LuaCreateVolZmapBox( lua_State* L)
    return 1 ;
 }
 
+//-------------------------------------------------------------------------------
+static int
+LuaCreateVolZMapEmpty( lua_State* L)
+{
+  // 6 o 7 o 8 parametri : ParentId, PtIni, dDimX, dDimY, dDimZ, dPrec [, bTriDex] [, nRefType]
+   int nParentId ;
+   LuaCheckParam( L, 1, nParentId)
+   Point3d ptIni ;
+   LuaCheckParam( L, 2, ptIni)
+   double dDimX ;
+   LuaCheckParam( L, 3, dDimX)
+   double dDimY ;
+   LuaCheckParam( L, 4, dDimY)
+   double dDimZ ;
+   LuaCheckParam( L, 5, dDimZ)
+   double dPrec ;
+   LuaCheckParam( L, 6, dPrec)
+   bool bTriDex = true ;
+   int nRefType = RTY_DEFAULT ;
+   if ( ! LuaGetParam( L, 7, bTriDex))
+      LuaGetParam( L, 7, nRefType) ;
+   else
+      LuaGetParam( L, 8, nRefType) ;
+   LuaClearStack( L) ;
+  // creo VZM da superficie trimesh 
+   int nId = ExeCreateVolZmapEmpty( nParentId, ptIni, dDimX, dDimY, dDimZ, dPrec, bTriDex, nRefType) ;
+  // restituisco il risultato
+   if ( nId != GDB_ID_NULL)
+      LuaSetParam( L, nId) ;
+   else
+      LuaSetParam( L) ;
+   return 1 ;
+}
+
 //-------------------------------------------------------------------------------
 static int
 LuaCreateVolZmapByRegionExtrusion( lua_State* L)
@@ -94,7 +128,7 @@ LuaCreateVolZmapFromSurfTm( lua_State* L)
    bool bTriDex = true ;
    LuaGetParam( L, 4, bTriDex) ;
    LuaClearStack( L) ;
-  // creo VZM da superficie trimesh 
+  // creo VZM da superficie trimesh
    int nId = ExeCreateVolZmapFromSurfTm( nParentId, nStmId, dPrec, bTriDex) ;
   // restituisco il risultato
    if ( nId != GDB_ID_NULL)
@@ -104,13 +138,33 @@ LuaCreateVolZmapFromSurfTm( lua_State* L)
    return 1 ;
 }
 
+//-------------------------------------------------------------------------------
+static int
+LuaUpdateVolZmapByAddingSurfTm( lua_State* L)
+{
+  // 3 ParentId, ZmapId, StmId
+   int nParentId ;
+   LuaCheckParam( L, 1, nParentId)
+   int nZmapId ;
+   LuaCheckParam( L, 2, nZmapId)
+   int nStmId ;
+   LuaCheckParam( L, 3, nStmId)
+   LuaClearStack( L) ;
+  // creo VZM da superficie trimesh
+   bool bOk = ExeUpdateVolZmapByAddingSurfTm( nParentId, nZmapId, nStmId) ;
+   LuaSetParam( L, bOk) ;
+   return 1 ;
+}
+
 //-------------------------------------------------------------------------------
 bool
 LuaInstallGdbCreateVol( LuaMgr& luaMgr)
 {
    bool bOk = ( &luaMgr != nullptr) ;
    bOk = bOk && luaMgr.RegisterFunction( "EgtVolZmapBox", LuaCreateVolZmapBox) ;
+   bOk = bOk && luaMgr.RegisterFunction( "EgtVolZmapEmpty", LuaCreateVolZMapEmpty) ;
    bOk = bOk && luaMgr.RegisterFunction( "EgtVolZmapByRegionExtrusion", LuaCreateVolZmapByRegionExtrusion) ;
    bOk = bOk && luaMgr.RegisterFunction( "EgtVolZmapFromSurfTm", LuaCreateVolZmapFromSurfTm) ;
+   bOk = bOk && luaMgr.RegisterFunction( "EgtUpdateVolZmapByAddingSurfTm", LuaUpdateVolZmapByAddingSurfTm) ;
    return bOk ;
 }