diff --git a/Axis.cpp b/Axis.cpp
index ead754a..f03318b 100644
--- a/Axis.cpp
+++ b/Axis.cpp
@@ -44,6 +44,7 @@ Axis::Clone( void) const
             pAx->m_pGeomDB = nullptr ;
             pAx->m_sName = m_sName ;
             pAx->m_sToken = m_sToken ;
+            pAx->m_bInvert = m_bInvert ;
             pAx->m_nType = m_nType ;
             pAx->m_ptPos = m_ptPos ;
             pAx->m_vtDir = m_vtDir ;
@@ -114,11 +115,12 @@ Axis::Axis( void)
 
 //----------------------------------------------------------------------------
 bool
-Axis::Set( const string& sName, const string& sToken, int nType,
+Axis::Set( const string& sName, const string& sToken, bool bInvert, int nType,
            const Point3d& ptPos, const Vector3d& vtDir, const STROKE& Stroke, double dHome)
 {
    m_sName = sName ;
    m_sToken = sToken ;
+   m_bInvert = bInvert ;
    m_nType = nType ;
    m_ptPos = ptPos ;
    m_vtDir = vtDir ;
diff --git a/Axis.h b/Axis.h
index d887e92..37b420c 100644
--- a/Axis.h
+++ b/Axis.h
@@ -30,7 +30,7 @@ class Axis : public IUserObj
 
    public :
       Axis( void) ;
-      bool Set( const std::string& sName, const std::string& sToken, int nType,
+      bool Set( const std::string& sName, const std::string& sToken, bool bInvert, int nType,
                 const Point3d& ptPos, const Vector3d& vtDir, const STROKE& Stroke, double dHome) ;
       bool Modify( const STROKE& Stroke) ;
       bool Modify( double dHome) ;
@@ -40,6 +40,8 @@ class Axis : public IUserObj
               { return m_sName ; }
       const std::string& GetToken( void) const
               { return m_sToken ; }
+      bool GetInvert( void) const
+              { return m_bInvert ; }
       int GetType( void) const
               { return m_nType ; }
       const Point3d& GetPos( void) const
@@ -58,6 +60,7 @@ class Axis : public IUserObj
       IGeomDB*    m_pGeomDB ;
       std::string m_sName ;
       std::string m_sToken ;
+      bool        m_bInvert ;
       int         m_nType ;
       Point3d     m_ptPos ;
       Vector3d    m_vtDir ;
diff --git a/Machine.cpp b/Machine.cpp
index 851ef32..b5808f4 100644
--- a/Machine.cpp
+++ b/Machine.cpp
@@ -272,7 +272,7 @@ Machine::AdjustTable( int nLay, const Point3d& ptRef1)
 
 //----------------------------------------------------------------------------
 bool
-Machine::LoadMachineAxis( const string& sName, const string& sParent, const string& sToken,
+Machine::LoadMachineAxis( const string& sName, const string& sParent, const string& sToken, bool bInvert,
                           int nType, const Point3d& ptPos, const Vector3d& vtDir, const STROKE& Stroke,
                           double dHome, bool bAdjustAux, const string& sGeo, const STRVECTOR& vsAux)
 {
@@ -314,7 +314,7 @@ Machine::LoadMachineAxis( const string& sName, const string& sParent, const stri
    Axis* pAxis = new(nothrow) Axis ;
    if ( pAxis == nullptr)
       return false ;
-   pAxis->Set( sName, sToken, nType, ptPos, vtDir, Stroke, dHome) ;
+   pAxis->Set( sName, sToken, bInvert, nType, ptPos, vtDir, Stroke, dHome) ;
    m_pGeomDB->SetUserObj( nLay, pAxis) ;
   // verifico il vettore rappresentativo dell'asse
    if ( ! AdjustAxis( nLay, sPart, sName, nType, ptPos, vtDir, bAdjustAux))
diff --git a/Machine.h b/Machine.h
index 631e3ac..c80e749 100644
--- a/Machine.h
+++ b/Machine.h
@@ -137,7 +137,7 @@ class Machine
                              const std::string& sGeo, const STRVECTOR& vsAux) ;
       bool AdjustTable( int nLay, const Point3d& ptRef1) ;
       bool LoadMachineAxis( const std::string& sName, const std::string& sParent, const std::string& sToken,
-                            int nType, const Point3d& ptPos, const Vector3d& vtDir, const STROKE& Stroke,
+                            bool bInvert, int nType, const Point3d& ptPos, const Vector3d& vtDir, const STROKE& Stroke,
                             double dHome, bool bAdjustAux, const std::string& sGeo, const STRVECTOR& vsAux) ;
       bool AdjustAxis( int nLay, const std::string& sPart, const std::string& sName,
                        int nType, const Point3d& ptPos, const Vector3d& vtDir, bool bAdjustAux) ;
diff --git a/MachineLua.cpp b/MachineLua.cpp
index 121cfd9..a820eb1 100644
--- a/MachineLua.cpp
+++ b/MachineLua.cpp
@@ -36,6 +36,7 @@ static const string FLD_GEO = "Geo" ;
 static const string FLD_AUX = "Aux" ;
 static const string FLD_TOKEN = "Token" ;
 static const string FLD_TYPE = "Type" ;
+static const string FLD_INVERT = "Invert" ;
 static const string FLD_REF1 = "Ref1" ;
 static const string FLD_SCALE = "Scale" ;
 static const string FLD_POS = "Pos" ;
@@ -393,6 +394,9 @@ Machine::LuaEmtAxis( lua_State* L)
   // lettura eventuale campo 'Token' dalla tabella (default Name)
    string sToken = sName ;
    LuaGetTabFieldParam( L, 1, FLD_TOKEN, sToken) ;
+  // lettura eventuale campo Invert dalla tabella (default false)
+   bool bInvert = false ;
+   LuaGetTabFieldParam( L, 1, FLD_TYPE, bInvert) ;
   // lettura campo 'Type' dalla tabella
    int nType ;
    LuaCheckTabFieldParam( L, 1, FLD_TYPE, nType)
@@ -428,7 +432,7 @@ Machine::LuaEmtAxis( lua_State* L)
       return luaL_error( L, " Unknown Machine") ;
 
   // carico i dati dell'asse
-   if ( ! m_pMchLua->LoadMachineAxis( sName, sParent, sToken, nType, ptPos, vtDir,
+   if ( ! m_pMchLua->LoadMachineAxis( sName, sParent, sToken, bInvert, nType, ptPos, vtDir,
                                       Stroke, dHome, bAdjustAux, sGeo, vsAux))
       return luaL_error( L, " Load Machine Axis failed") ;
 
diff --git a/MachiningsMgr.cpp b/MachiningsMgr.cpp
index 66d0ff0..471b482 100644
--- a/MachiningsMgr.cpp
+++ b/MachiningsMgr.cpp
@@ -903,9 +903,11 @@ MachiningsMgr::GetCurrMachiningParam( int nType, std::string& sVal) const
 bool
 MachiningsMgr::Set3AxComp( bool b3AxComp)
 {
-  // salvo e setto modifica
-   m_b3AxComp = b3AxComp ;
-   m_bModified = true ;
+  // se cambiato, salvo e setto modifica
+   if ( b3AxComp != m_b3AxComp) {
+      m_b3AxComp = b3AxComp ;
+      m_bModified = true ;
+   }
    return true ;
 }
 
@@ -913,9 +915,11 @@ MachiningsMgr::Set3AxComp( bool b3AxComp)
 bool
 MachiningsMgr::Set5AxComp( bool b5AxComp)
 {
-  // salvo e setto modifica
-   m_b5AxComp = b5AxComp ;
-   m_bModified = true ;
+  // se cambiato, salvo e setto modifica
+   if ( b5AxComp != m_b5AxComp) {
+      m_b5AxComp = b5AxComp ;
+      m_bModified = true ;
+   }
    return true ;
 }
 
@@ -1002,6 +1006,9 @@ MachiningsMgr::SetSplitArcs( int nFlag)
 {
    if ( nFlag < SPLAR_NEVER  ||  nFlag > SPLAR_ALWAYS)
       return false ;
-   m_nSplitArcs = nFlag ;
+   if ( nFlag != m_nSplitArcs) {
+      m_nSplitArcs = nFlag ;
+      m_bModified = true ;
+   }
    return true ;
 }