diff --git a/SurfBezier.cpp b/SurfBezier.cpp
index c072092..b74b70c 100644
--- a/SurfBezier.cpp
+++ b/SurfBezier.cpp
@@ -1500,9 +1500,9 @@ SurfBezier::GetAuxSurf( void) const
    // costruttore della superficie
    
    Tree Tree( this, true) ;
-   //Tree.BuildTree_test() ;
+   Tree.BuildTree_test() ;
    //Tree.BuildTree( 0.05, 1) ;
-   Tree.BuildTree( 0.5, 10) ;
+   //Tree.BuildTree( 0.5, 10) ;
    //Tree.BuildTree( 1, 25) ;
    vector<POLYLINEVECTOR> vvPL ;
    Tree.GetPolygons( vvPL) ;
@@ -1547,9 +1547,9 @@ bool
 SurfBezier::GetLeaves( std::vector<std::tuple<int, Point3d, Point3d>>& vLeaves) const
 {
    Tree Tree( this, true) ;
-   //Tree.BuildTree_test() ;
+   Tree.BuildTree_test() ;
    //Tree.BuildTree( 0.05, 1) ;
-   Tree.BuildTree( 0.5, 10) ;
+   //Tree.BuildTree( 0.5, 10) ;
    //Tree.BuildTree( 1, 25) ;
    std::vector<Cell> vCells ;
    Tree.GetLeaves( vCells) ;
diff --git a/Tree.cpp b/Tree.cpp
index 23c5e5d..a357514 100644
--- a/Tree.cpp
+++ b/Tree.cpp
@@ -1434,7 +1434,7 @@ Tree::FindCell( const Point3d& ptToAssign, CurveLine& clTrim) const
    
    // se ho diviso preliminarmente le patches e in uno dei due parametri ho un numero dispari di patches devo individuare a mano la cella parent
    // in cui individuare la foglia giusta
-   if (  m_bSplitPatches  &&  ( (m_nSpanU % 2 != 0  &&  m_nSpanU > 1)  ||  (m_nSpanV % 2 != 0  &&  m_nSpanV > 1))) {
+   if (  m_bSplitPatches  &&  ( m_nSpanU > 1  ||  m_nSpanV > 1)) {
       INTVECTOR nParents = FindCell( ptToAssign, clTrim, m_vnParents) ;
       nId = nParents.back() ;
    }
@@ -1664,7 +1664,7 @@ Tree::TraceLoopLabelCell( void)
          // aggiungo la fine del segmento nel vettore delle intersezioni
          vptInters.push_back( ptCurr) ;
       }
-      if ( AreSamePointExact( ptCurr, ptStart))
+      if ( nId == nFirstCell)
          vptInters.pop_back() ;
       m_mTree[nId].m_vInters.back().vpt = vptInters ;
       if ( bLoopInside) {
@@ -1683,16 +1683,18 @@ Tree::TraceLoopLabelCell( void)
       else {
          // verifico se sono effettivamente nella cella di partenza o nella penultima cella
          // devo verificare se il loop finisce in un vertice! in questo caso sono nella penultima cella! e devo fare un FindInters di nuovo per sistemare
-         //Point3d ptLast = m_mTree[nId].m_vInters.back().vpt.back() ;
-         Point3d ptLast = ptCurr ;
+         Point3d ptLast = m_mTree[nId].m_vInters.back().vpt.back() ; // devo recuperare l'intersezione del trim con i bordi delle celle////////////////////
+         //Point3d ptLast = ptCurr ;
          if ( nId != nFirstCell) {
             Point3d ptTl( m_mTree[nId].GetBottomLeft().x, m_mTree[nId].GetTopRight().y) ;
             Point3d ptBr( m_mTree[nId].GetTopRight().x, m_mTree[nId].GetBottomLeft().y) ;
-            int nLastId ;
+            int nLastId, nEdge ;
+            // qui devo tener conto anche della possibilità che il trim termini parzialmente coincidente con un lato///////////////////////////////////
             if ( AreSamePointApprox( m_mTree[nId].GetTopRight(), ptLast) ||
                  AreSamePointApprox( ptTl, ptLast) ||
                  AreSamePointApprox( m_mTree[nId].GetBottomLeft(), ptLast) ||
-                 AreSamePointApprox( ptBr, ptLast)) {
+                 AreSamePointApprox( ptBr, ptLast)  ||
+                 OnWhichEdge( nId, ptLast,nEdge)) {
                Point3d ptTStart, ptTEnd ;
                plLoop.GetPrevPoint( ptTEnd) ;
                plLoop.GetPrevPoint( ptTStart) ;
@@ -1733,6 +1735,12 @@ Tree::TraceLoopLabelCell( void)
                m_mTree[nFirstCell].m_vInters[nPass].nIn = 5 ;
             else if (AreSamePointApprox( ptBr, ptFirst))
                m_mTree[nFirstCell].m_vInters[nPass].nIn = 6 ;
+            // sono su un lato e non su un vertice
+            else {
+               int nEdge ;
+               OnWhichEdge( nFirstCell, ptFirst, nEdge) ;
+               m_mTree[nFirstCell].m_vInters[nPass].nIn = nEdge ;
+            }
          }
       }
    }
@@ -2619,7 +2627,7 @@ Tree::CreateIslandAndHoles( int nLeafId, std::vector<POLYLINEVECTOR>& vPolygons,
                for( int c = 0 ; c < nInters ; ++ c){
                   inB = m_mTree[nId].m_vInters[c] ;
                   if ( inB.nIn == -1) {
-                     if ( inB != inA  &&  inB.nChunk == inA.nChunk) {
+                     if ( inB != inA  &&  inB.nChunk == inA.nChunk  &&  inB.bCCW) {
                         bContained = true ;
                         break ;
                      }
@@ -3416,3 +3424,25 @@ Tree::GetLeaves( std::vector<Cell>& vLeaves) const
    
    return true ;
 }
+
+//----------------------------------------------------------------------------
+bool
+Tree::OnWhichEdge( int nId, Point3d& ptToAssign, int& nEdge) const
+{
+   Point3d ptTR = m_mTree.at(nId).GetTopRight() ;
+   Point3d ptBL = m_mTree.at(nId).GetBottomLeft() ;
+   Point3d ptTl ( ptBL.x, ptTR.y) ;
+   Point3d ptBr ( ptTR.x, ptBL.y) ;
+
+   if ( ptToAssign.x >= ptBL.x  &&  ptToAssign.x <= ptTR.x  &&  abs( ptToAssign.y - ptTR.y) < EPS_SMALL)
+      nEdge = 0 ;
+   else if ( ptToAssign.y >= ptBL.y  &&  ptToAssign.y <= ptTR.y  &&  abs( ptToAssign.x - ptBL.x) < EPS_SMALL)
+      nEdge = 1 ;
+   else if ( ptToAssign.x >= ptBL.x  &&  ptToAssign.x <= ptTR.x  &&  abs( ptToAssign.y - ptBL.y) < EPS_SMALL)
+      nEdge = 2 ;
+   else if ( ptToAssign.y >= ptBL.y  &&  ptToAssign.y <= ptTR.y  &&  abs( ptToAssign.x - ptTR.x) < EPS_SMALL)
+      nEdge = 3 ;
+   else
+      return false ;
+   return true ;
+}
diff --git a/Tree.h b/Tree.h
index 39e5333..62a3830 100644
--- a/Tree.h
+++ b/Tree.h
@@ -45,7 +45,7 @@ struct Inters {
          pl.GetAreaXY( dAreaB) ;
       }
       return nIn < b.nIn  ||
-         ( bEqIn  &&  nIn == -1  &&  dAreaA > dAreaB)  ||
+         ( bEqIn  &&  nIn == -1  &&  abs(dAreaA) > abs(dAreaB))  ||
          ( bEqIn  &&  nIn == 0  &&  vpt[0].x > b.vpt[0].x)  ||
          ( bEqIn  &&  nIn == 1  &&  vpt[0].y > b.vpt[0].y)  ||
          ( bEqIn  &&  nIn == 2  &&  vpt[0].x < b.vpt[0].x)  ||
@@ -156,6 +156,7 @@ private :
    bool SetRightEdgeIn( int nId) ;
    bool CategorizeCell( int& nId) ;
    bool CheckIfBetween( Inters& inA, Inters& inB) const ;
+   bool OnWhichEdge( int nId, Point3d& ptToAssign, int& nEdge) const ;
 
 private :
    const SurfBezier*           m_pSrfBz ;           // superficie di bezier