diff --git a/SurfBezier.cpp b/SurfBezier.cpp
index 60f52e0..b8c35ba 100644
--- a/SurfBezier.cpp
+++ b/SurfBezier.cpp
@@ -4767,6 +4767,8 @@ SurfBezier::CreateByTwoCurves( const ICurve* pCurve0, const ICurve* pCurve1, int
       // in quel punto la curva verrà spezzata, a meno che non si trovi una joint già sufficientemente vicina
 
       // prima trovo le associazioni senza aggiunte di punti
+      bool bIsClosed0 = plU0.IsClosed() ;
+      bool bIsClosed1 = plU1.IsClosed() ;
       Point3d ptP1 ; plU1.GetFirstPoint( ptP1) ;
       vector<pair<Point3d,double>> vMatch1 ;
       while ( plU1.GetNextPoint( ptP1, true)) {
@@ -4796,8 +4798,10 @@ SurfBezier::CreateByTwoCurves( const ICurve* pCurve0, const ICurve* pCurve1, int
          int nFlag = 0 ;
          double dParam ; dpc.GetParamAtMinDistPoint( 0, dParam, nFlag) ;
          Point3d ptJoint ; dpc.GetMinDistPoint( 0, ptJoint, nFlag) ;
+         if( bIsClosed1 && dParam > nSpanU1 - EPS_SMALL)
+            dParam = 0 ;
          vdMatch0.push_back( dParam) ;
-         if ( dParam < EPS_SMALL ) {
+         if ( dParam < EPS_SMALL) {
             ++nAtStart1 ;
             vbRep0[c] = true ;
             ++c ;
@@ -4870,7 +4874,9 @@ SurfBezier::CreateByTwoCurves( const ICurve* pCurve0, const ICurve* pCurve1, int
          int nFlag = 0 ;
          double dParam ; dpc.GetParamAtMinDistPoint( 0, dParam, nFlag) ;
          Point3d ptJoint ; dpc.GetMinDistPoint( 0, ptJoint, nFlag) ;
-         if ( dParam < EPS_SMALL ) {
+         if ( bIsClosed0 && dParam > nSpanU0 - EPS_SMALL)
+            dParam = 0 ;
+         if ( dParam < EPS_SMALL) {
             ++nAtStart0 ;
             vbRep1[c] = true ;
             ++c ;