diff --git a/EXE_GdbModifySurf.cpp b/EXE_GdbModifySurf.cpp
index d82ad1b..fc1dd40 100644
--- a/EXE_GdbModifySurf.cpp
+++ b/EXE_GdbModifySurf.cpp
@@ -25,6 +25,7 @@
 #include "/EgtDev/Include/EGkSurfFlatRegion.h"
 #include "/EgtDev/Include/EGkSurfTriMesh.h"
 #include "/EgtDev/Include/EGkSurfLocal.h"
+#include "/EgtDev/Include/EGkStmFromTriangleSoup.h"
 #include "/EgtDev/Include/EGkCAvSimpleSurfFrMove.h"
 #include "/EgtDev/Include/EGkStringUtils3d.h"
 #include "/EgtDev/Include/EgtPointerOwner.h"
@@ -63,7 +64,7 @@ ExeInvertSurface( const INTVECTOR& vIds)
 
 //-------------------------------------------------------------------------------
 static int
-MyExplodeSurfTriMesh( int nId, int* pnCount)
+MyExplodeSurfTriMesh( int nId, int& nCount)
 {
    IGeomDB* pGeomDB = GetCurrGeomDB() ;
    VERIFY_GEOMDB( pGeomDB, GDB_ID_NULL)
@@ -76,7 +77,7 @@ MyExplodeSurfTriMesh( int nId, int* pnCount)
   // se ci sono più parti, separo queste
    if ( nParts > 1) {
       int nFirstId = GDB_ID_NULL ;
-      int nCount = 0 ;
+      nCount = 0 ;
       for ( int i = 0 ; i < nParts ; ++ i) {
          ISurfTriMesh* pFac = pStm->ClonePart( i) ;
          if ( pFac == nullptr)
@@ -96,8 +97,6 @@ MyExplodeSurfTriMesh( int nId, int* pnCount)
      // elimino la superficie originale
       pGeomDB->Erase( nId) ;
      // restituisco risultati
-      if ( pnCount != nullptr)
-         *pnCount = nCount ;
       return nFirstId ;
    }
   // recupero il numero di facce
@@ -106,7 +105,7 @@ MyExplodeSurfTriMesh( int nId, int* pnCount)
    if ( nFacets > 1) {
      // copio tutte le facce
       int nFirstId = GDB_ID_NULL ;
-      int nCount = 0 ;
+      nCount = 0 ;
       for ( int i = 0 ; i < nFacets ; ++ i) {
          ISurfTriMesh* pFac = pStm->CloneFacet( i) ;
          if ( pFac == nullptr)
@@ -126,19 +125,16 @@ MyExplodeSurfTriMesh( int nId, int* pnCount)
      // elimino la superficie originale
       pGeomDB->Erase( nId) ;
      // restituisco risultati
-      if ( pnCount != nullptr)
-         *pnCount = nCount ;
       return nFirstId ;
    }
   // non devo fare alcunché
-   if ( pnCount != nullptr)
-      *pnCount = 1 ;
+   nCount = 1 ;
    return nId ;
 }
 
 //-------------------------------------------------------------------------------
 static int
-MyExplodeSurfFlatRegion( int nId, int* pnCount)
+MyExplodeSurfFlatRegion( int nId, int& nCount)
 {
    IGeomDB* pGeomDB = GetCurrGeomDB() ;
    VERIFY_GEOMDB( pGeomDB, GDB_ID_NULL)
@@ -150,13 +146,12 @@ MyExplodeSurfFlatRegion( int nId, int* pnCount)
    int nChunk = pSfr->GetChunkCount() ;
   // se c'è un solo componente, non devo fare alcunché
    if ( nChunk == 1) {
-      if ( pnCount != nullptr)
-         *pnCount = 1 ;
+      nCount = 1 ;
       return nId ;
    }
   // copio tutti i componenti connessi (chunk)
    int nFirstId = GDB_ID_NULL ;
-   int nCount = 0 ;
+   nCount = 0 ;
    for ( int i = 0 ; i < nChunk ; ++ i) {
       ISurfFlatRegion* pChk = pSfr->CloneChunk( i) ;
       if ( pChk == nullptr)
@@ -176,8 +171,6 @@ MyExplodeSurfFlatRegion( int nId, int* pnCount)
   // elimino la superficie
    pGeomDB->Erase( nId) ;
   // restituisco risultati
-   if ( pnCount != nullptr)
-      *pnCount = nCount ;
    return nFirstId ;
 }
 
@@ -192,10 +185,10 @@ ExeExplodeSurface( int nId, int* pnCount)
    int nCount = 0 ;
    switch ( pGeomDB->GetGeoType( nId)) {
    case SRF_TRIMESH :
-      nFirstId = MyExplodeSurfTriMesh( nId, &nCount) ;
+      nFirstId = MyExplodeSurfTriMesh( nId, nCount) ;
       break ;
    case SRF_FLATRGN :
-      nFirstId = MyExplodeSurfFlatRegion( nId, &nCount) ;
+      nFirstId = MyExplodeSurfFlatRegion( nId, nCount) ;
       break ;
    }
    ExeSetModified() ;
@@ -845,3 +838,96 @@ ExeSurfTmIntersect( int nId1, int nId2)
    }
    return bOk ;
 }
+
+//----------------------------------------------------------------------------
+static ISurfTriMesh*
+MyCreateSubSurfTm( const ISurfTriMesh* pStm, const INTVECTOR& vTria)
+{
+   StmFromTriangleSoup StmFts ;
+   if ( ! StmFts.Start())
+      return nullptr ;
+   for ( int nT : vTria) {
+      Triangle3d Tria ;
+      if ( ! pStm->GetTriangle( nT, Tria)  ||
+           ! StmFts.AddTriangle( Tria))
+         return nullptr ;
+   }
+  // valido la superficie e calcolo le adiacenze
+   if ( ! StmFts.End())
+      return nullptr ;
+  // restituisco la superficie
+   return StmFts.GetSurf() ; 
+}
+
+//----------------------------------------------------------------------------
+static int 
+MySurfTmSplit( int nId, int nSplitterId, int& nCount)
+{
+   IGeomDB* pGeomDB = GetCurrGeomDB() ;
+   VERIFY_GEOMDB( pGeomDB, GDB_ID_NULL)
+  // recupero la superficie TriMesh da dividere in parti
+   ISurfTriMesh* pStm = GetSurfTriMesh( pGeomDB->GetGeoObj( nId)) ;
+   if ( pStm == nullptr)
+      return GDB_ID_NULL ;
+  // recupero il riferimento della superficie
+   Frame3d frSurf ;
+   if ( ! pGeomDB->GetGlobFrame( nId, frSurf))
+      return GDB_ID_NULL ;
+  // recupero la superficie TriMesh divisore in locale alla prima
+   SurfLocal SurfCLoc( pGeomDB, nSplitterId, frSurf) ;
+   const ISurfTriMesh* pStmCLoc = GetSurfTriMesh( SurfCLoc) ;
+   if ( pStmCLoc == nullptr)
+      return GDB_ID_NULL ;
+  // eseguo la classificazione
+   INTVECTOR vTriaIn, vTriaOut, vTriaOnP, vTriaOnM, vTriaIndef ;
+   if ( ! pStm->GetSurfClassification( *pStmCLoc, vTriaIn, vTriaOut, vTriaOnP, vTriaOnM, vTriaIndef))
+      return GDB_ID_NULL ;
+  // costruisco le diverse superfici
+   PtrOwner<ISurfTriMesh> pStmIn( MyCreateSubSurfTm( pStm, vTriaIn)) ;
+   PtrOwner<ISurfTriMesh> pStmOut( MyCreateSubSurfTm( pStm, vTriaOut)) ;
+   PtrOwner<ISurfTriMesh> pStmOnP( MyCreateSubSurfTm( pStm, vTriaOnP)) ;
+   PtrOwner<ISurfTriMesh> pStmOnM( MyCreateSubSurfTm( pStm, vTriaOnM)) ;
+   PtrOwner<ISurfTriMesh> pStmIndef( MyCreateSubSurfTm( pStm, vTriaIndef)) ;
+   if ( IsNull( pStmIn)  ||  IsNull( pStmOut)  ||  IsNull( pStmOnP)  ||  IsNull( pStmOnM)  ||  IsNull( pStmIndef))
+      return GDB_ID_NULL ;
+  // le inserisco nel DB geometrico
+   int nStmIn = pGeomDB->InsertGeoObj( GDB_ID_NULL, nId, GDB_BEFORE, Release( pStmIn)) ;
+   int nStmOut = pGeomDB->InsertGeoObj( GDB_ID_NULL, nId, GDB_BEFORE, Release( pStmOut)) ;
+   int nStmOnP = pGeomDB->InsertGeoObj( GDB_ID_NULL, nId, GDB_BEFORE, Release( pStmOnP)) ;
+   int nStmOnM = pGeomDB->InsertGeoObj( GDB_ID_NULL, nId, GDB_BEFORE, Release( pStmOnM)) ;
+   int nStmIndef = pGeomDB->InsertGeoObj( GDB_ID_NULL, nId, GDB_BEFORE, Release( pStmIndef)) ;
+  // se tutto ok
+   if ( nStmIn != GDB_ID_NULL  &&  nStmOut != GDB_ID_NULL  &&  nStmOnP != GDB_ID_NULL  &&  nStmOnM != GDB_ID_NULL  &&  nStmIndef != GDB_ID_NULL) {
+      pGeomDB->Erase( nId) ;
+      nCount = 5 ;
+      return nStmIn ;
+   }
+   else {
+      pGeomDB->Erase( nStmIn) ;
+      pGeomDB->Erase( nStmOut) ;
+      pGeomDB->Erase( nStmOnP) ;
+      pGeomDB->Erase( nStmOnM) ;
+      pGeomDB->Erase( nStmIndef) ;
+      nCount = 0 ;
+      return GDB_ID_NULL ;
+   }
+}
+
+//----------------------------------------------------------------------------
+int
+ExeSurfTmSplit( int nId, int nSplitterId, int* pnCount)
+{
+   int nCount ;
+   int nFirstId = MySurfTmSplit( nId, nSplitterId, nCount) ;
+   ExeSetModified() ;
+  // se richiesto, salvo il comando Lua equivalente
+   if ( IsCmdLog()) {
+      string sLua = "EgtSurfTmSplit(" + ToString( nId) + "," +
+                                        ToString( nSplitterId) + ")" +
+                    " -- Id1=" + ToString( nFirstId) + ",Nbr=" + ToString( nCount) ;
+      LOG_INFO( GetCmdLogger(), sLua.c_str()) ;
+   }
+   if ( pnCount != nullptr)
+      *pnCount = nCount ;
+   return nFirstId ;
+}
diff --git a/EgtExecutor.rc b/EgtExecutor.rc
index add0c1c..81a1b11 100644
Binary files a/EgtExecutor.rc and b/EgtExecutor.rc differ
diff --git a/LUA_GdbModifySurf.cpp b/LUA_GdbModifySurf.cpp
index 4ed44fe..ec339fb 100644
--- a/LUA_GdbModifySurf.cpp
+++ b/LUA_GdbModifySurf.cpp
@@ -448,6 +448,27 @@ LuaSurfTmIntersect( lua_State* L)
    return 1 ;
 }
 
+//-------------------------------------------------------------------------------
+static int
+LuaSurfTmSplit( lua_State* L)
+{
+  // 2 parametro : nId, nSplitterId
+   int nId ;
+   LuaCheckParam( L, 1, nId)
+   int nSplitterId ;
+   LuaCheckParam( L, 2, nSplitterId)
+   LuaClearStack( L) ;
+  // divido la prima superficie in base alla seconda
+   int nCount ;
+   int nFirstId = ExeSurfTmSplit( nId, nSplitterId, &nCount) ;
+   if ( nFirstId != GDB_ID_NULL)
+      LuaSetParam( L, nFirstId) ;
+   else
+      LuaSetParam( L) ;
+   LuaSetParam( L, nCount) ;
+   return 2 ;
+}
+
 //-------------------------------------------------------------------------------
 bool
 LuaInstallGdbModifySurf( LuaMgr& luaMgr)
@@ -474,5 +495,6 @@ LuaInstallGdbModifySurf( LuaMgr& luaMgr)
    bOk = bOk && luaMgr.RegisterFunction( "EgtSurfTmAdd", LuaSurfTmAdd) ;
    bOk = bOk && luaMgr.RegisterFunction( "EgtSurfTmSubtract", LuaSurfTmSubtract) ;
    bOk = bOk && luaMgr.RegisterFunction( "EgtSurfTmIntersect", LuaSurfTmIntersect) ;
+   bOk = bOk && luaMgr.RegisterFunction( "EgtSurfTmSplit", LuaSurfTmSplit) ;
    return bOk ;
 }