diff --git a/VolZmapGraphics.cpp b/VolZmapGraphics.cpp
index 90c85fb..b07419c 100644
--- a/VolZmapGraphics.cpp
+++ b/VolZmapGraphics.cpp
@@ -1,13 +1,13 @@
 //----------------------------------------------------------------------------
-//  EgalTech 2015-2019
+//  EgalTech 2015-2021
 //----------------------------------------------------------------------------
-// File : VolZmap.cpp         Data : 07.03.19           Versione : 2.1c2
+// File : VolZmap.cpp         Data : 13.09.21           Versione : 2.3i1
 // Contenuto : Implementazione della classe Volume Zmap (tre griglie)
 //
 //
 //
 // Modifiche : 22.01.15 DS Creazione modulo.
-//
+//             13.09.21 LM Correzione funzione che determina se voxel su frontiera di un blocco.
 //
 //----------------------------------------------------------------------------
 
@@ -3984,13 +3984,13 @@ VolZmap::IsAVoxelOnBoundary( const int nLimits[], const int nIJK[], int nDeltaIn
       -- nDeltaIndex[0] ;
    else if ( nIJK[0] == nLimits[1] - 1)
       ++ nDeltaIndex[0] ;   
-   if ( nIJK[0] == nLimits[0])
+   if ( nIJK[1] == nLimits[2])
       -- nDeltaIndex[1];
-   else if ( nIJK[0] == nLimits[1] - 1)
+   else if ( nIJK[1] == nLimits[3] - 1)
       ++ nDeltaIndex[1];   
-   if ( nIJK[0] == nLimits[0])
+   if ( nIJK[2] == nLimits[4])
       -- nDeltaIndex[2];
-   else if ( nIJK[0] == nLimits[1] - 1)
+   else if ( nIJK[2] == nLimits[5] - 1)
       ++ nDeltaIndex[2];   
    return ( nDeltaIndex[0] != 0  ||  nDeltaIndex[1] != 0  ||  nDeltaIndex[2] != 0) ;
 }