diff --git a/SceneSnap.cpp b/SceneSnap.cpp
index 5601128..0a0e893 100644
--- a/SceneSnap.cpp
+++ b/SceneSnap.cpp
@@ -851,8 +851,8 @@ Scene::FindSurfFRSnapPoint( int nSnap, const Point3d& ptWin, int nId, const Fram
    bool bFound = false ;
    for ( int i = 0 ; i < pSfr->GetChunkCount() ; ++ i) {
       for ( int j = 0 ; j < pSfr->GetLoopCount( i) ; ++ j) {
-         ICurve* pCrv = pSfr->GetLoop( i, j) ;
-         if ( pCrv == nullptr)
+         PtrOwner<ICurve> pCrv( pSfr->GetLoop( i, j)) ;
+         if ( IsNull( pCrv))
             return false ;
          if ( pCrv->GetType() == CRV_COMPO) {
             ICurveComposite* pCrvCompo = GetCurveComposite( pCrv) ;