diff --git a/VolZmap.cpp b/VolZmap.cpp
index f31e17d..9688119 100644
--- a/VolZmap.cpp
+++ b/VolZmap.cpp
@@ -1194,6 +1194,12 @@ VolZmap::ClonePart( int nPart) const
       pVolume->m_Values[nMap].resize( pVolume->m_nDim[nMap]) ;
    }
 
+  // Se almeno due griglie nulle, non ha senso Zmap
+   if ( pVolume->m_nDim[0] + pVolume->m_nDim[1] == 0  ||
+        pVolume->m_nDim[0] + pVolume->m_nDim[2] == 0  ||
+        pVolume->m_nDim[1] + pVolume->m_nDim[2] == 0)
+      return nullptr ;
+
   // Copio gli intervalli nelle griglie del nuovo oggetto:
   // Griglia 0
    for ( int nIndJ = 0 ; nIndJ < int( pVolume->m_nNy[0]) ; ++ nIndJ) {