diff --git a/VolTriZmapCreation.cpp b/VolTriZmapCreation.cpp
index 7b79422..0afffae 100644
--- a/VolTriZmapCreation.cpp
+++ b/VolTriZmapCreation.cpp
@@ -146,11 +146,11 @@ VolZmap::Create( const Point3d& ptO, double dLengthX, double dLengthY, double dL
    }
 
   // Ridimensiono e setto il vettore dei blocchi a falso
-   int BlockVecSize = m_nFracLin[0] * m_nFracLin[1] * m_nFracLin[2] ;
+   m_nNumBlock = m_nFracLin[0] * m_nFracLin[1] * m_nFracLin[2] ;
 
-   m_BlockToUpdate.resize( BlockVecSize) ;
+   m_BlockToUpdate.resize( m_nNumBlock) ;
 
-   for ( int nCount = 0 ; nCount < BlockVecSize ; ++ nCount)
+   for ( unsigned int nCount = 0 ; nCount < m_nNumBlock ; ++ nCount)
 
       m_BlockToUpdate[nCount] = true ;
   
@@ -380,11 +380,11 @@ VolZmap::CreateFromFlatRegion( const ISurfFlatRegion& Surf, double dDimZ, double
    }
 
   // Ridimensiono e setto il vettore dei blocchi a falso
-   int BlockVecSize = m_nFracLin[0] * m_nFracLin[1] * m_nFracLin[2] ;
+   m_nNumBlock = m_nFracLin[0] * m_nFracLin[1] * m_nFracLin[2] ;
 
-   m_BlockToUpdate.resize( BlockVecSize) ;
+   m_BlockToUpdate.resize( m_nNumBlock) ;
 
-   for ( int nCount = 0 ; nCount < BlockVecSize ; ++ nCount)
+   for ( unsigned int nCount = 0 ; nCount < m_nNumBlock ; ++ nCount)
 
       m_BlockToUpdate[nCount] = true ;
    
@@ -667,11 +667,11 @@ VolZmap::CreateFromTriMesh( const ISurfTriMesh& Surf, double dPrec, bool bFlag)
    }
 
   // Ridimensiono e setto il vettore dei blocchi a falso
-   int BlockVecSize = m_nFracLin[0] * m_nFracLin[1] * m_nFracLin[2] ;
+   m_nNumBlock = m_nFracLin[0] * m_nFracLin[1] * m_nFracLin[2] ;
 
-   m_BlockToUpdate.resize( BlockVecSize) ;
+   m_BlockToUpdate.resize( m_nNumBlock) ;
 
-   for ( int nCount = 0 ; nCount < BlockVecSize ; ++ nCount)
+   for ( unsigned int nCount = 0 ; nCount < m_nNumBlock ; ++ nCount)
 
       m_BlockToUpdate[nCount] = true ;               
 
diff --git a/VolTriZmapGraphics.cpp b/VolTriZmapGraphics.cpp
index c37ca6e..e8b10a7 100644
--- a/VolTriZmapGraphics.cpp
+++ b/VolTriZmapGraphics.cpp
@@ -223,6 +223,8 @@ VolZmap::GetBlockTriangles( int nBlock, TRIA3DLIST& lstTria) const
       //ExtMarchingCubes( nBlock, lstTria, triHold) ;
 
       MarchingCubes( nBlock, lstTria) ;
+          
+   m_BlockToUpdate[nBlock] = false ;
 
    return true ;
 }
@@ -235,6 +237,13 @@ VolZmap::GetBlockInfo( std::vector<bool> & bModified) const
    return true ;
 }
 
+//----------------------------------------------------------------------------
+int
+VolZmap::GetBlockCount( void) const
+{
+   return m_nNumBlock ;
+}
+
 //----------------------------------------------------------------------------
 bool
 VolZmap::GetChunkPrisms( int nPos1, int nPos2, int nDim1, int nDim2, int nDimChk, TRIA3DLIST& lstTria) const
@@ -649,8 +658,6 @@ VolZmap::MarchingCubes( int nBlock, TRIA3DLIST& lstTria) const
          }
       }
    }
-          
-   m_BlockToUpdate[nBlock] = false ;
 
    return true ;
 }
diff --git a/VolZmap.h b/VolZmap.h
index 246e6d4..961ddd2 100644
--- a/VolZmap.h
+++ b/VolZmap.h
@@ -73,8 +73,9 @@ class VolZmap : public IVolZmap, public IGeoObjRW
       bool CreateFromFlatRegion( const ISurfFlatRegion& Surf, double dDimZ, double dPrec, bool bTriDex) override ;
       bool CreateFromTriMesh( const ISurfTriMesh& Surf, double dPrec, bool bTriDex) override ;
       bool GetAllTriangles( TRIA3DLIST& lstTria) const override ;
-      bool GetBlockTriangles( int nBlock, TRIA3DLIST& lstTria) const override ;
+      int  GetBlockCount( void) const override ;
       bool GetBlockInfo( std::vector<bool> & bModified) const override ;
+      bool GetBlockTriangles( int nBlock, TRIA3DLIST& lstTria) const override ;
       bool GetDexelLines( int nDir, int nPos1, int nPos2, POLYLINELIST& lstPL) const override ;
       bool SetTolerances( double dLinTol, double dAngTolDeg = 90) override ;
       bool SetStdTool( const std::string& pToolName, double dH, double dR, double dCornR) override ;
@@ -233,7 +234,7 @@ class VolZmap : public IVolZmap, public IGeoObjRW
    private :
       enum Status { ERR = 0, OK = 1, TO_VERIFY = 2} ;
       static const int N_MAPS = 3 ;
-      static const int N_DEXBLOCK = 10000 ;
+      static const int N_DEXBLOCK = 32 ;
 
    private :
       ObjGraphicsMgr m_OGrMgr ;             // gestore grafica dell'oggetto
@@ -256,7 +257,7 @@ class VolZmap : public IVolZmap, public IGeoObjRW
       std::vector<std::vector<Data>> m_Values[N_MAPS] ;  // dexel delle 3 griglie
 
       unsigned int m_nDexNumPBlock ;        // Numero di dexel per blocco
-      unsigned int m_nFracLin[3] ;          // Numero di blocchi per per ogni asse           
+      unsigned int m_nFracLin[3] ;          // Numero di blocchi per ogni asse           
       unsigned int m_nNumBlock ;            // Numero totale di blocchi
 
       mutable std::vector<bool> m_BlockToUpdate ;