diff --git a/CurveAux.cpp b/CurveAux.cpp
index 4bc1c70..a47fb8e 100644
--- a/CurveAux.cpp
+++ b/CurveAux.cpp
@@ -2043,13 +2043,14 @@ CalcCurvesMedialAxis( const CICURVEPVECTOR& vCrvC, ICURVEPOVECTOR& vCrvs, int nS
 
 //----------------------------------------------------------------------------
 bool 
-CalcCurveFatCurve( const ICurve& crvC, ICURVEPOVECTOR& vCrvs, double dRadius, bool bSquareEnds, bool bSquareMids)
+CalcCurveFatCurve( const ICurve& crvC, ICURVEPOVECTOR& vCrvs, double dRadius, bool bSquareEnds, bool bSquareMids,
+                   bool bMergeOnlySameProps)
 {
    Voronoi* pVoronoiObj = GetCurveVoronoi( crvC) ;
    if ( pVoronoiObj == nullptr)
       return false ;
 
-   return pVoronoiObj->CalcFatCurve( vCrvs, dRadius, bSquareEnds, bSquareMids) ; 
+   return pVoronoiObj->CalcFatCurve( vCrvs, dRadius, bSquareEnds, bSquareMids, bMergeOnlySameProps) ; 
 }
 
 //----------------------------------------------------------------------------
diff --git a/SfrCreate.cpp b/SfrCreate.cpp
index cc18437..4535e90 100644
--- a/SfrCreate.cpp
+++ b/SfrCreate.cpp
@@ -115,7 +115,8 @@ GetSurfFlatRegionDisk( double dRadius)
 
 //-------------------------------------------------------------------------------
 ISurfFlatRegion*
-GetSurfFlatRegionFromFatCurve( ICurve* pCrv, double dRadius, bool bSquareEnds, bool bSquareMids, double dOffsLinTol)
+GetSurfFlatRegionFromFatCurve( ICurve* pCrv, double dRadius, bool bSquareEnds, bool bSquareMids, double dOffsLinTol,
+                               bool bMergeOnlySameProps)
 {
   // metodo di calcolo impostato da USE_VORONOI
 
@@ -330,7 +331,7 @@ GetSurfFlatRegionFromFatCurve( ICurve* pCrv, double dRadius, bool bSquareEnds, b
    else {   
      // calcolo la fat curve con Voronoi
       ICURVEPOVECTOR vFatCurves ;
-      if ( ! CalcCurveFatCurve( *pCurve, vFatCurves, dRadius, bSquareEnds, bSquareMids))
+      if ( ! CalcCurveFatCurve( *pCurve, vFatCurves, dRadius, bSquareEnds, bSquareMids, bMergeOnlySameProps))
          return nullptr ;
 
      // costruisco la superficie a partire dalle curve
diff --git a/Voronoi.cpp b/Voronoi.cpp
index 8321f49..4feb971 100644
--- a/Voronoi.cpp
+++ b/Voronoi.cpp
@@ -847,18 +847,19 @@ Voronoi::CalcSpecialPointOffset( PNTVECTVECTOR& vResult, double dOffs)
 
 //----------------------------------------------------------------------------
 bool 
-Voronoi::CalcFatCurve( ICURVEPOVECTOR& vCrvs, double dOffs, bool bSquareEnds, bool bSquareMids)
+Voronoi::CalcFatCurve( ICURVEPOVECTOR& vCrvs, double dOffs, bool bSquareEnds, bool bSquareMids,
+                       bool bMergeOnlySameProps)
 {
    vCrvs.clear() ;
  
    if ( ! IsValid())
-      return false ; 
- 
-  // se offset nullo errore
-   if ( abs( dOffs) < EPS_SMALL) 
       return false ;
  
-   ICRVCOMPOPLIST OffsList ; 
+  // se offset nullo errore
+   if ( abs( dOffs) < EPS_SMALL)
+      return false ;
+ 
+   ICRVCOMPOPLIST OffsList ;
    if ( ! CalcVroniOffset( OffsList, abs( dOffs)))
       return false ;
   
@@ -873,7 +874,7 @@ Voronoi::CalcFatCurve( ICURVEPOVECTOR& vCrvs, double dOffs, bool bSquareEnds, bo
      // identifico i raccordi da modificare
       if ( bClosed  &&  bSquareMids) {
         // se curva è chiusa tutti i raccordi rispondono a bSquareMids
-         IdentifyFillets( pCrvOffs, dOffs) ;  
+         IdentifyFillets( pCrvOffs, dOffs) ;
       }
       else if ( ! bClosed  &&  (  bSquareMids  ||  bSquareEnds)) {
         // se curva è aperta devo distinguere i raccordi interni da quelli relativi agli estremi e 
@@ -889,9 +890,9 @@ Voronoi::CalcFatCurve( ICURVEPOVECTOR& vCrvs, double dOffs, bool bSquareEnds, bo
       }
 
      // unisco le parti allineate
-      pCrvOffs->MergeCurves( LIN_TOL_MIN, ANG_TOL_STD_DEG, true, true) ;
+      pCrvOffs->MergeCurves( LIN_TOL_MIN, ANG_TOL_STD_DEG, true, bMergeOnlySameProps) ;
      // aggiungo al vettore finale
-      vCrvs.emplace_back( pCrvOffs) ;     
+      vCrvs.emplace_back( pCrvOffs) ;
    }
 
   // sistemo i raccordi
diff --git a/Voronoi.h b/Voronoi.h
index 8f6e1fc..d0f033b 100644
--- a/Voronoi.h
+++ b/Voronoi.h
@@ -57,7 +57,7 @@ class Voronoi
       bool CalcOffset( ICURVEPOVECTOR& vOffs, double dOffs, int nType) ;
       bool CalcSingleCurvesOffset( ICURVEPOVECTOR& vOffs, double dOffs) ;
       bool CalcSpecialPointOffset( PNTVECTVECTOR& vResult, double dOffs) ;
-      bool CalcFatCurve( ICURVEPOVECTOR& vOffs, double dOffs, bool bSquareEnds, bool bSquareMids) ;
+      bool CalcFatCurve( ICURVEPOVECTOR& vOffs, double dOffs, bool bSquareEnds, bool bSquareMids, bool bMergeOnlySameProps = true) ;
       bool CalcMedialAxis( ICURVEPOVECTOR& vCrvs, int nSide) ;
       bool CalcLimitOffset( int nCrv, bool bLeft, double& dOffs) ;