diff --git a/VolZmap.cpp b/VolZmap.cpp
index 1142da6..39af1f9 100644
--- a/VolZmap.cpp
+++ b/VolZmap.cpp
@@ -1680,3 +1680,10 @@ VolZmap::SetChiselTool( const string& sToolName, double dH, double dW, double dT
 {
    return m_Tool.SetChiselTool( sToolName, dH, dW, dTh, nFlag) ; 
 }
+
+//----------------------------------------------------------------------------
+bool 
+VolZmap::ResetTool( void)
+{
+   return m_Tool.Clear() ; 
+}
diff --git a/VolZmap.h b/VolZmap.h
index ae5c7cf..25d9ee0 100644
--- a/VolZmap.h
+++ b/VolZmap.h
@@ -84,6 +84,7 @@ class VolZmap : public IVolZmap, public IGeoObjRW
       bool SetGenTool( const std::string& sToolName, const ICurveComposite* pToolOutline, int nFlag) override ;
       bool SetMortiserTool( const std::string& sToolName, double dH, double dW, double dTh, double dRc, int nFlag) override ;
       bool SetChiselTool( const std::string& sToolName, double dH, double dW, double dTh, int nFlag) override ;
+      bool ResetTool( void) override ;
       const ICurveComposite& GetToolOutline( bool bApprox = false) const override
                   { return ( bApprox ? m_Tool.GetApproxOutline() : m_Tool.GetOutline()) ;}
       bool MillingStep( const Point3d& ptPs, const Vector3d& vtDs, const Point3d& ptPe, const Vector3d& vtDe) override ;
diff --git a/VolZmapVolume.cpp b/VolZmapVolume.cpp
index 2a5d36c..9abd4c3 100644
--- a/VolZmapVolume.cpp
+++ b/VolZmapVolume.cpp
@@ -489,6 +489,9 @@ VolZmap::MillingStep( const Point3d& ptPs, const Vector3d& vtDs, const Point3d&
 bool
 VolZmap::MillingStep( const Point3d& ptPs, const Vector3d& vtDs, const Vector3d& vtAs, const Point3d& ptPe, const Vector3d& vtDe, const Vector3d& vtAe)
 {
+  // Se non è definito l'utensile, non devo fare alcunchè
+   if ( m_Tool.GetType() == Tool::UNDEF)
+      return true ;
   // Controllo definizione vettori direzione
    if ( vtDs.IsSmall()  ||  vtDe.IsSmall())
       return false ;