diff --git a/WaterJetting.cpp b/WaterJetting.cpp
index acc7688..747d2fe 100644
--- a/WaterJetting.cpp
+++ b/WaterJetting.cpp
@@ -1814,7 +1814,7 @@ WaterJetting::GeneratePreView( int nPathId, const ICurveComposite* pCompo, const
    PtrOwner<ISurfFlatRegion> pSfr ;
    double dSideCoeff = ( abs( m_Params.m_dSideAngle) > EPS_ANG_SMALL ? 1. / cos( m_Params.m_dSideAngle * DEGTORAD) : 1) ;
    double dRad = 0.5 * m_TParams.m_dDiam * dSideCoeff ;
-   pSfr.Set( GetSurfFlatRegionFromFatCurve( Release( pCrv), dRad, false, false)) ;
+   pSfr.Set( GetSurfFlatRegionFromFatCurve( Release( pCrv), dRad, false, true)) ;
    if ( IsNull( pSfr))
       return false ;
   // aggiungo eventuali anelli su angoli esterni