diff --git a/Tree.cpp b/Tree.cpp
index 4c97432..c911a49 100644
--- a/Tree.cpp
+++ b/Tree.cpp
@@ -2350,6 +2350,8 @@ Tree::TraceLoopLabelCell( const POLYLINEVECTOR& vplPolygons)
       Point3d ptCurr ;
       auto iter = find( m_vnLeaves.begin(), m_vnLeaves.end(), nId) ;
       int nIdPolygon = distance( m_vnLeaves.begin(), iter) ;
+      if ( nIdPolygon > int( vplPolygons.size()) - 1)
+         return false ;
       bool bEraseNextPoint = false ;
       while ( plLoop.GetNextPoint( ptCurr)) {
          Point3d ptTStart, ptTEnd ;
@@ -2385,6 +2387,8 @@ Tree::TraceLoopLabelCell( const POLYLINEVECTOR& vplPolygons)
             // ricalcolo la posizione di nId nel vettore delle foglie
             iter = find( m_vnLeaves.begin(), m_vnLeaves.end(), nId) ;
             nIdPolygon = distance( m_vnLeaves.begin(), iter) ;
+            if ( nIdPolygon > int( vplPolygons.size()) - 1)
+               return false ;
             // aggiorno il puntatore alla cella
             pCell = &m_mTree[nId] ;
             // salvo il verso del loop