diff --git a/EgtMachKernel.rc b/EgtMachKernel.rc
index a9594c9..0118598 100644
Binary files a/EgtMachKernel.rc and b/EgtMachKernel.rc differ
diff --git a/Operation.cpp b/Operation.cpp
index a1f92df..9096b5a 100644
--- a/Operation.cpp
+++ b/Operation.cpp
@@ -3306,6 +3306,23 @@ Operation::GetZHomeDown( void) const
    return bZHomeDown ;
 }
 
+//----------------------------------------------------------------------------
+static bool
+ResetMachine( Machine* pMch)
+{
+  // macchina non definita
+   if ( pMch == nullptr)
+      return false ;
+  // Riporto la macchina in home
+   pMch->ResetAllAxesPos() ;
+  // Sgancio pezzi, grezzi e sottopezzi dalla tavola corrente
+   pMch->UnlinkAllPartsFromGroups() ;
+   pMch->UnlinkAllRawPartsFromGroups() ;
+   pMch->UnlinkAllFixturesFromGroups() ;
+  // tutto bene
+   return true ;
+}
+
 //----------------------------------------------------------------------------
 bool
 Operation::TestCollisionAvoid( const DBLVECTOR& vAxStart, const DBLVECTOR& vAxEnd) const
@@ -3349,6 +3366,14 @@ Operation::TestCollisionAvoid( const DBLVECTOR& vAxStart, const DBLVECTOR& vAxEn
   // Parti di testa e collegati da considerare per la collisione
    INTVECTOR vCollId ;
    pMch->GetCurrHeadCollGroups( vCollId) ;
+
+  // Lancio la verifica custom
+   int nRes = SpecialTestCollisionAvoid( vAxStart, vAxEnd) ;
+   if ( nRes != SCAV_TOTEST) {
+      ResetMachine( pMch) ;
+      return ( nRes == SCAV_AVOID) ;
+   }
+
   // distanza di sicurezza
    const double TOL_SAFEDIST = 5.0 ;
    const double MIN_SAFEDIST = 5.0 ;
@@ -3504,16 +3529,65 @@ Operation::TestCollisionAvoid( const DBLVECTOR& vAxStart, const DBLVECTOR& vAxEn
          }
       }
    }
-  // Riporto la macchina in home
-   pMch->ResetAllAxesPos() ;
-  // Sgancio pezzi, grezzi e sottopezzi dalla tavola corrente
-   pMch->UnlinkAllPartsFromGroups() ;
-   pMch->UnlinkAllRawPartsFromGroups() ;
-   pMch->UnlinkAllFixturesFromGroups() ;
+  // Ripristino lo stato macchina
+   ResetMachine( pMch) ;
 
    return ( ! bCollide) ;
 }
 
+//----------------------------------------------------------------------------
+int
+Operation::SpecialTestCollisionAvoid( const DBLVECTOR& vAxStart, const DBLVECTOR& vAxEnd) const
+{
+  // recupero la macchina corrente
+   Machine* pMch = ( m_pMchMgr != nullptr ?  m_pMchMgr->GetCurrMachine() : nullptr) ;
+   if ( pMch == nullptr)
+      return false ;
+
+  // assi già verificati
+
+  // costanti
+   static const string EMC_VAR = "EMC" ;              // tabella variabili locali per calcolo
+   static const string EVAR_ERROR = ".ERR" ;          // OUT (int) codice di errore (0=ok)
+   static const string EVAR_RES = ".RES" ;            // OUT (int) risultato (0=collide, 1=evita, 2=fare test standard) 
+   static const string ON_SPECIAL_TESTCOLLISIONAVOID = "OnSpecialTestCollisionAvoid" ;
+
+  // verifico definizione funzione
+   if ( ! pMch->LuaExistsFunction( ON_SPECIAL_TESTCOLLISIONAVOID))
+      return SCAV_TOTEST ;
+
+  // avvio
+   bool bOk = true ;
+   int nErr = 99 ;
+  // imposto valori parametri
+   bOk = bOk && pMch->LuaCreateGlobTable( EMC_VAR) ;
+   bOk = bOk && pMch->LuaSetGlobVar( EMC_VAR + GVAR_TOOL, GetToolName()) ;
+   bOk = bOk && pMch->LuaSetGlobVar( EMC_VAR + GVAR_HEAD, GetHeadName()) ;
+   bOk = bOk && pMch->LuaSetGlobVar( EMC_VAR + GVAR_EXIT, GetExitNbr()) ;
+   bOk = bOk && pMch->LuaSetGlobVar( EMC_VAR + GVAR_TCPOS, GetToolTcPos()) ;
+   bOk = bOk && pMch->LuaSetGlobVar( EMC_VAR + GVAR_MCHID, GetOwner()) ;
+   // valori degli assi
+   for ( int i = 1 ; i <= int( vAxStart.size()) ; ++ i)
+      bOk = bOk && pMch->LuaSetGlobVar( GetGlobVarAxisPrev( i, EMC_VAR), vAxStart[i-1]) ;
+   for ( int i = 1 ; i <= int( vAxEnd.size()) ; ++ i)
+      bOk = bOk && pMch->LuaSetGlobVar( GetGlobVarAxisValue( i, EMC_VAR), vAxEnd[i-1]) ;
+  // eseguo
+   bOk = bOk && pMch->LuaCallFunction( ON_SPECIAL_TESTCOLLISIONAVOID, false) ;
+  // recupero valori parametri obbligatori
+   bOk = bOk && pMch->LuaGetGlobVar( EMC_VAR + EVAR_ERROR, nErr) ;
+   int nRes = SCAV_TOTEST ;
+   bOk = bOk && pMch->LuaGetGlobVar( EMC_VAR + EVAR_RES, nRes) ;
+  // reset
+   bOk = bOk && pMch->LuaResetGlobVar( EMC_VAR) ;
+  // segnalo errori
+   if ( nErr != 0) {
+      bOk = false ;
+      string sOut = "  Error in " + ON_SPECIAL_TESTCOLLISIONAVOID + " (" + ToString( nErr) + ")" ;
+      LOG_ERROR( GetEMkLogger(), sOut.c_str())
+   }
+   return ( nErr != 0 ? SCAV_ERROR : nRes) ;
+}
+
 //----------------------------------------------------------------------------
 bool
 Operation::SpecialMoveZup( DBLVECTOR& vAx, Vector3d& vtTool, int& nFlag, int& nFlag2, bool& bModif)
diff --git a/Operation.h b/Operation.h
index 282f161..bb8dc25 100644
--- a/Operation.h
+++ b/Operation.h
@@ -153,7 +153,8 @@ class Operation : public IUserObj
       int    GetUserNotesZmax( void) const ;
       bool   GetZHomeDown( void) const ;
       bool   TestCollisionAvoid( const DBLVECTOR& vAxStart, const DBLVECTOR& vAxEnd) const ;
-      bool   SpecialMoveZup( DBLVECTOR& vAx, Vector3d& vtTool, int& nFlag, int& nFlag2,  bool& bModif) ;
+      int    SpecialTestCollisionAvoid( const DBLVECTOR& vAxStart, const DBLVECTOR& vAxEnd) const ;
+      bool   SpecialMoveZup( DBLVECTOR& vAx, Vector3d& vtTool, int& nFlag, int& nFlag2, bool& bModif) ;
       bool   SpecialMoveRapid(  const DBLVECTOR& vAxStart, const DBLVECTOR& vAxEnd, DBLVECTOR& vAxNew, bool& bModif) ;
 
       bool   GetAggrBottomData( const std::string& sHead, AggrBottom& agbData) const ;
@@ -219,3 +220,5 @@ inline Operation* GetOperation( IUserObj* pUserObj)
 enum { TOOL_PARAL = 1, TOOL_ORTHO = 2, TOOL_ORTUP = 3, TOOL_PAR_SLANT= 4} ;
 // tipo di utilizzo contorno faccia
 enum { FACE_DOWN = 1, FACE_TOP = 2, FACE_FRONT = 3, FACE_BACK = 4, FACE_LEFT = 5, FACE_RIGHT = 6, FACE_CONT = 7} ;
+// risultato di SpecialTestCollisionAvoid 
+enum { SCAV_ERROR = -1, SCAV_COLLIDE = 0, SCAV_AVOID = 1, SCAV_TOTEST = 2};