diff --git a/EXE_GdbModifyCurve.cpp b/EXE_GdbModifyCurve.cpp
index f7c4b29..882061c 100644
--- a/EXE_GdbModifyCurve.cpp
+++ b/EXE_GdbModifyCurve.cpp
@@ -747,7 +747,7 @@ MyTrimCurveWithRegion( int nCrvId, int nRegId, bool bInVsOut, bool bOn, int& nCo
    if ( ! pSFR->GetCurveClassification( *CrvLoc, ccClass))
       return GDB_ID_NULL ;
   // determino gli intervalli di curva da conservare
-   Intervals inOk ;
+   Intervals inOk( 100 * EPS_PARAM) ;
    for ( auto& ccOne : ccClass) {
       if ( ( bInVsOut  &&  ccOne.nClass == CRVC_IN)  ||
            ( ! bInVsOut  &&  ccOne.nClass == CRVC_OUT)  ||
@@ -756,9 +756,11 @@ MyTrimCurveWithRegion( int nCrvId, int nRegId, bool bInVsOut, bool bOn, int& nCo
    }
   // recupero un intervallo di id contigui per tutte le parti
    int nFirstId = pGeomDB->GetNewId() ;
+   if ( nFirstId == nCrvId + 1)
+      nFirstId = nCrvId ;
+   int nCurrId = nFirstId ;
    if ( ! pGeomDB->ChangeId( nCrvId, nFirstId))
       return GDB_ID_NULL ;
-   int nCurrId = nFirstId ;
   // eseguo la divisione
    nCount = 0 ;
    double dParS, dParE ;
@@ -863,6 +865,8 @@ MyTrimFlatCurveWithBox( int nCrvId, const Frame3d& frBox, const Vector3d& vtDiag
    }
   // recupero un intervallo di id contigui per tutte le parti
    int nFirstId = pGeomDB->GetNewId() ;
+   if ( nFirstId == nCrvId + 1)
+      nFirstId = nCrvId ;
    if ( ! pGeomDB->ChangeId( nCrvId, nFirstId))
       return GDB_ID_NULL ;
    int nCurrId = nFirstId ;
@@ -934,6 +938,8 @@ ExeSplitCurve( int nId, int nParts)
    bOk = bOk && ( dLen > 10 * EPS_SMALL) ;
   // recupero un intervallo di id contigui per tutte le parti
    int nFirstId = pGeomDB->GetNewId() ;
+   if ( nFirstId == nId + 1)
+      nFirstId = nId ;
    bOk = bOk && pGeomDB->ChangeId( nId, nFirstId) ;
    int nCurrId = nFirstId ;
   // eseguo la divisione
@@ -1094,6 +1100,8 @@ ExeSplitCurveAtCorners( int nId, double dTgAngToler, int* pnCount)
    }
   // recupero un intervallo di id contigui per tutte le parti
    int nFirstId = pGeomDB->GetNewId() ;
+   if ( nFirstId == nId + 1)
+      nFirstId = nId ;
    bOk = bOk && pGeomDB->ChangeId( nId, nFirstId) ;
    int nCurrId = nFirstId ;
   // eseguo la divisione
@@ -1175,6 +1183,8 @@ ExeSplitCurveAtSelfInters( int nId, int* pnCount)
    }
   // recupero un intervallo di id contigui per tutte le parti
    int nFirstId = pGeomDB->GetNewId() ;
+   if ( nFirstId == nId + 1)
+      nFirstId = nId ;
    bOk = bOk && pGeomDB->ChangeId( nId, nFirstId) ;
    int nCurrId = nFirstId ;
   // eseguo la divisione
diff --git a/EXE_NstCreateFlatParts.cpp b/EXE_NstCreateFlatParts.cpp
index 1cc4f3d..63098d4 100644
--- a/EXE_NstCreateFlatParts.cpp
+++ b/EXE_NstCreateFlatParts.cpp
@@ -872,6 +872,8 @@ VerifyPrepareFlatParts( void)
          }
         // recupero un intervallo di id contigui per tutte le parti
          int nFirstId = pGeomDB->GetNewId() ;
+         if ( nFirstId == vOpenIds[i] + 1)
+            nFirstId = vOpenIds[i] ;
          pGeomDB->ChangeId( vOpenIds[i], nFirstId) ;
          int nCurrId = nFirstId ;
         // eseguo la divisione
diff --git a/EgtExecutor.rc b/EgtExecutor.rc
index 8da70b0..0cf3df1 100644
Binary files a/EgtExecutor.rc and b/EgtExecutor.rc differ