diff --git a/EGkHashGrids1d.h b/EGkHashGrids1d.h
new file mode 100644
index 0000000..cbdfb49
--- /dev/null
+++ b/EGkHashGrids1d.h
@@ -0,0 +1,76 @@
+//----------------------------------------------------------------------------
+//  EgalTech 2015-2018
+//----------------------------------------------------------------------------
+// File : EGkHashGrids1d.h        Data : 02.05.21          Versione : 2.4e1
+// Contenuto : Dichiarazione della classe HashGrids1d.
+//
+//
+//
+// Modifiche : 04.07.15 DS Creazione modulo.
+//            
+//
+//----------------------------------------------------------------------------
+
+#pragma once
+
+#include "EgtDev/Include/EGkBBox3d.h"
+#include "EgtDev/Include/EgtNumCollection.h"
+#include <unordered_map>
+
+//----------------------- Macro per import/export ----------------------------
+#undef EGK_EXPORT
+#if defined( I_AM_EGK)            // da definirsi solo nella DLL
+#define EGK_EXPORT __declspec( dllexport)
+#else
+#define EGK_EXPORT __declspec( dllimport)
+#endif
+
+//----------------------------------------------------------------------------
+class HashGrids1d
+{
+public :
+   EGK_EXPORT HashGrids1d( void) ;
+   EGK_EXPORT ~HashGrids1d( void) ;
+   EGK_EXPORT void SetActivationGrid( bool bActivate) ;
+   EGK_EXPORT bool Add( int nObjId, const BBox3d& box) ;
+   EGK_EXPORT bool Modify( int nObjId, const BBox3d& box) ;
+   EGK_EXPORT bool Remove( int nObjId) ;
+   EGK_EXPORT bool Update( void) ;
+   EGK_EXPORT bool Find( const BBox3d& b3Test, INTVECTOR& vnIds) const ;
+   EGK_EXPORT void Clear( void) ;
+
+   friend class HashGrid1d ;
+
+private :
+   struct ObjData {
+      int         nId ;
+      BBox3d      box ;
+      HashGrid1d* pHGrid ;
+      size_t      nHash ;
+      size_t      nCellId ;
+      ObjData( void)
+         : nId( -1), box(), pHGrid( nullptr), nHash( 0), nCellId( 0) {}
+      ObjData( int nI, const BBox3d& bb, HashGrid1d* pHG, size_t nH, size_t nCI)
+         : nId( nI), box( bb), pHGrid( pHG), nHash( nH), nCellId( nCI) {}
+   } ;
+   typedef std::list<ObjData> ObjList ; 
+   typedef std::vector<ObjData*> PtrObjVector ;
+   typedef std::unordered_map<int,ObjData*> IntPObjUmap ;
+
+private :
+   typedef std::list<HashGrid1d*> GridList ;  // Tipo per lista di hash grid
+
+private :
+   void addGrid( ObjData& obj) ;
+   void addList( ObjData& obj) ;
+
+private :
+   ObjList      m_ObjsList ;     // Lista degli oggetti
+   IntPObjUmap  m_ObjsMap ;      // Map da Id a PtrObj
+   PtrObjVector m_objsToAdd ;    // Vettore di puntatori agli oggetti da inserire
+   PtrObjVector m_nonGridObjs ;  // Vettore di puntatori agli oggetti non assegnati alle griglie (per dimensioni o perchè pochi)
+   GridList     m_GridList ;     // Lista delle griglie di dimensione fissa ( in ordine crescente di dimensione di cella) 
+   bool         m_bActivate ;    // Flag che abilita l'attivazione delle griglie
+   bool         m_bGridActive ;  // Flag di attivazione delle griglie
+   BBox3d       m_b3Objs ;       // Box totale di tutti gli oggetti inseriti
+} ;
diff --git a/EGkIntersPlaneSurfTm.h b/EGkIntersPlaneSurfTm.h
index 12fcbdf..a06e2f2 100644
--- a/EGkIntersPlaneSurfTm.h
+++ b/EGkIntersPlaneSurfTm.h
@@ -14,6 +14,7 @@
 #pragma once
 
 #include "/EgtDev/Include/EGkSurfTriMesh.h"
+#include "/EgtDev/Include/EGkHashGrids1d.h"
 
 //----------------------- Macro per import/export ----------------------------
 #undef EGK_EXPORT
@@ -26,3 +27,18 @@
 //-----------------------------------------------------------------------------
 EGK_EXPORT bool IntersPlaneSurfTm( const Plane3d& plPlane, const ISurfTriMesh& Stm,
                                    PNTVECTOR& vPnt, BIPNTVECTOR& vBpt, TRIA3DVECTOR& vTria) ;
+
+
+//-----------------------------------------------------------------------------
+class IntersParPlanesSurfTm
+{
+public :
+   EGK_EXPORT IntersParPlanesSurfTm( const Frame3d& frPlanes, const ISurfTriMesh& Stm) ;
+   EGK_EXPORT bool GetInters( const Point3d& ptPl, PNTVECTOR& vPnt, BIPNTVECTOR& vBpt, TRIA3DVECTOR& vTria) const ;
+
+private :
+   bool                m_bOk ;
+   const Frame3d       m_frPlanes ;
+   const ISurfTriMesh* m_pSTm ;
+   HashGrids1d         m_HGrids ;
+} ;
\ No newline at end of file
diff --git a/EXeExecutor.h b/EXeExecutor.h
index 5428d62..76a3545 100644
--- a/EXeExecutor.h
+++ b/EXeExecutor.h
@@ -737,6 +737,8 @@ EXE_EXPORT int  ExePlaneBoxInters( const Point3d& ptOn, const Vector3d& vtN, con
 EXE_EXPORT bool ExeLineSurfTmInters( const Point3d& ptP, const Vector3d& vtDir, int nId, int nRefType, INTDBLVECTOR& vInters) ;
 EXE_EXPORT int  ExePlaneSurfTmInters( const Point3d& ptOn, const Vector3d& vtN, int nId, int nDestGrpId, int nRefType, double dToler,
                                       int* pnPntCount, int* pnCrvCount, int* pnSrfCount) ;
+EXE_EXPORT int ExeParPlanesSurfTmInters( const Vector3d& vtN, const PNTVECTOR& vPntPlanes, int nId, int nDestGrpId, int nRefType, double dToler,
+                                         int* pnGrpCount) ;
 EXE_EXPORT int  ExeSurfTmSurfTmInters( int nId1, int nId2, int nDestGrpId, double dToler,
                                        int* pnPntCount, int* pnCrvCount, int* pnSrfCount) ;
 EXE_EXPORT bool ExeLineVolZmapInters( const Point3d& ptP, const Vector3d& vtDir, int nId, int nRefType, INTDBLVECTOR& vInters) ;