diff --git a/SurfTriMeshBooleans.cpp b/SurfTriMeshBooleans.cpp
index eca908b..21f052c 100644
--- a/SurfTriMeshBooleans.cpp
+++ b/SurfTriMeshBooleans.cpp
@@ -495,7 +495,7 @@ SurfTriMesh::GeneralizedCut( const ICurve& cvCurve, bool bSaveOnEq)
             vPL.emplace_back( plInLoop) ;
             PNTVECTOR vPt ;
             INTVECTOR vTr ;
-            if ( Triangulate().Make( vPL, vPt, vTr)) {
+            if ( Triangulate().Make( vPL, vPt, vTr, TrgType::TRG_DEL_QUALITY)) {
               // Inserisco i nuovi triangoli
                for ( int n = 0 ; n < int( vTr.size()) - 2 ; n += 3) {
                   int nNewTriaVertId[3] = { vTr[n], vTr[n + 1], vTr[n + 2] } ;
@@ -711,7 +711,7 @@ SurfTriMesh::GeneralizedCut( const ICurve& cvCurve, bool bSaveOnEq)
                Triangulate CreateTriangulation ;
                PNTVECTOR vPt ;
                INTVECTOR vTr ;
-               if ( Triangulate().Make( vplPolyVec[nLoop], vPt, vTr)) {
+               if ( Triangulate().Make( vplPolyVec[nLoop], vPt, vTr, TrgType::TRG_DEL_QUALITY)) {
                  // Inserisco i nuovi triangoli
                   for ( int n = 0 ; n < int( vTr.size()) - 2 ; n += 3) {
                      int nNewTriaVertId[3] = { vTr[n], vTr[n + 1], vTr[n + 2] } ;
@@ -1350,7 +1350,7 @@ SurfTriMesh::RetriangulationForBooleanOperation( CHAINMAP& LoopLines, TRIA3DVECT
            // Eseguo triangolazione
             PNTVECTOR vPt ;
             INTVECTOR vTr ;
-            if ( Triangulate().Make( vplPolyVec[nLoop], vPt, vTr)) {
+            if ( Triangulate().Make( vplPolyVec[nLoop], vPt, vTr, TrgType::TRG_DEL_QUALITY)) {
               // Inserisco i nuovi triangoli
                for ( int n = 0 ; n < int( vTr.size()) - 2 ; n += 3) {
                   int nNewTriaVertId[3] = { vTr[n], vTr[n + 1], vTr[n + 2] } ;
@@ -1446,7 +1446,7 @@ SurfTriMesh::RetriangulationForBooleanOperation( CHAINMAP& LoopLines, TRIA3DVECT
 
             PNTVECTOR vPt ;
             INTVECTOR vTr ;
-            if ( Triangulate().Make( vPolygons, vPt, vTr)) {
+            if ( Triangulate().Make( vPolygons, vPt, vTr, TrgType::TRG_DEL_QUALITY)) {
                // Inserisco i nuovi triangoli
                for ( int n = 0 ; n < int( vTr.size()) - 2 ; n += 3) {
                   int nNewTriaVertId[3] = { vTr[n], vTr[n + 1], vTr[n + 2]} ;
@@ -1582,7 +1582,7 @@ SurfTriMesh::RetriangulationForBooleanOperation( CHAINMAP& LoopLines, TRIA3DVECT
             }
             for ( int nL = 1 ; nL < int( vPolygons.size()) ; ++ nL) {
                vPolygons[nL].Invert() ;
-               if ( Triangulate().Make( vPolygons[nL], vPt, vTr)) {
+               if ( Triangulate().Make( vPolygons[nL], vPt, vTr, TrgType::TRG_DEL_QUALITY)) {
                   // Inserisco i nuovi triangoli
                   for  (int n = 0 ; n < int( vTr.size()) - 2 ; n += 3) {
                      int nNewTriaVertId[3] = { vTr[n], vTr[n + 1], vTr[n + 2]} ;
@@ -4270,7 +4270,7 @@ SurfTriMesh::RetriangulateFacetPieces( const PieceMap& NewFacet,
       for ( int nPart = 0 ; nPart < nPartNum ; ++ nPart) {
          PNTVECTOR vPt ;
          INTVECTOR vTr ;
-         if ( Triangulate().Make( PiecesVector[nPart].vPieceLoop, vPt, vTr)) {
+         if ( Triangulate().Make( PiecesVector[nPart].vPieceLoop, vPt, vTr, TrgType::TRG_DEL_QUALITY)) {
             // Inserisco i nuovi triangoli
             for ( int n = 0 ; n < int( vTr.size()) - 2 ; n += 3) {
                int nNewTriaVertId[3] = { vTr[n], vTr[n + 1], vTr[n + 2]} ;
@@ -4362,7 +4362,7 @@ SurfTriMesh::RetriangulateFacetPieces( const PieceMap& NewFacet,
             bool bContinue = SplitPolyLineContour( PiecesVector[nPart].vPieceLoop, vSubPieceLoop[0], vSubPieceLoop[1]) ;
             while ( bContinue) {
                for ( int nSub = 0 ; nSub < int( vSubPieceLoop.size()) ; ++ nSub) {
-                  if (Triangulate().Make(vSubPieceLoop[nSub], vPt, vTr)) {
+                  if (Triangulate().Make(vSubPieceLoop[nSub], vPt, vTr, TrgType::TRG_DEL_QUALITY)) {
                      // Inserisco i nuovi triangoli
                      for (int n = 0; n < int(vTr.size()) - 2; n += 3) {
                         int nNewTriaVertId[3] = { vTr[n], vTr[n + 1], vTr[n + 2] };
diff --git a/Triangulate.cpp b/Triangulate.cpp
index 408f3d4..8341936 100644
--- a/Triangulate.cpp
+++ b/Triangulate.cpp
@@ -233,18 +233,31 @@ Triangulate::Make( const POLYLINEVECTOR& vPL, PNTVECTOR& vPt, INTVECTOR& vTr, Tr
 bool 
 Triangulate::MakeByDelaunay( const POLYLINEVECTOR& vPL, PNTVECTOR& vPt, INTVECTOR& vTr, bool bConforming, bool bQuality) 
 {
+   Plane3d plPlane ;
+   double dArea;
+   if ( ! vPL[0].IsClosedAndFlat( plPlane, dArea, 50 * EPS_SMALL))
+      return false ;
+   Frame3d frLoc ;
+   frLoc.Set( plPlane.GetPoint(), plPlane.GetVersN()) ;
+    
+   POLYLINEVECTOR vMyPL = vPL ;
+   for ( size_t t = 0 ; t < vPL.size() ; ++ t) {
+      vMyPL[t].ToLoc( frLoc) ; 
+   }
+
   // vertici e constraint per la triangolazione 
    vector<Delaunay::Point> vDelaunayVert ;
-   INTVECTOR vDelaunayConstr ;              
+   INTVECTOR vDelaunayConstr ;     
+ 
 
-   for ( size_t i = 0 ; i < vPL.size() ; i++) {      
+   for ( size_t i = 0 ; i < vMyPL.size() ; i++) {      
       Point3d ptFirst, pt ;
-      vPL[i].GetFirstPoint( ptFirst) ;
+      vMyPL[i].GetFirstPoint( ptFirst) ;
       vDelaunayVert.push_back( Delaunay::Point( ptFirst.x, ptFirst.y)) ;
       int nFirst = vDelaunayVert.size() - 1 ;  // indice del primo punto della polyline fra i vertici della triangolazione
       vDelaunayConstr.push_back( nFirst) ;
       
-      while ( vPL[i].GetNextPoint( pt)) {
+      while ( vMyPL[i].GetNextPoint( pt)) {
          vDelaunayVert.push_back( Delaunay::Point( pt.x, pt.y)) ;
         // nei constraint gli indici vanno inseriti due volte perchè vengono letti a due a due per definire un segmento
          vDelaunayConstr.push_back( vDelaunayVert.size() - 1) ;
@@ -259,14 +272,14 @@ Triangulate::MakeByDelaunay( const POLYLINEVECTOR& vPL, PNTVECTOR& vPt, INTVECTO
 
   // holes : sono definiti da un punto interno al buco  
    std::vector<Delaunay::Point> vDelaunayHoles ;
-   for ( size_t i = 1 ; i < vPL.size() ; i++) {
+   for ( size_t i = 1 ; i < vMyPL.size() ; i++) {
       Point3d pt ;      
       CurveComposite * pCrvHole = CreateBasicCurveComposite() ;
-      pCrvHole->FromPolyLine( vPL[i]) ;
+      pCrvHole->FromPolyLine( vMyPL[i]) ;
       pCrvHole->GetCentroid( pt) ;
      // se il centroide fosse esterno, cerco per tentativi un punto qualsiasi all'interno della curva 
       double dPar = 0.5 ;
-      while ( ! IsPointInsidePolyLine( pt, vPL[i])) {
+      while ( ! IsPointInsidePolyLine( pt, vMyPL[i])) {
          double dParS, dParE ;
          pCrvHole->GetDomain( dParS, dParE) ;
          if ( dPar > dParE)
@@ -284,9 +297,9 @@ Triangulate::MakeByDelaunay( const POLYLINEVECTOR& vPL, PNTVECTOR& vPt, INTVECTO
 
   // parti concave 
    PNTVECTOR vPtConvexHull ;
-   vPL[0].GetConvexHullXY( vPtConvexHull) ;
+   vMyPL[0].GetConvexHullXY( vPtConvexHull) ;
    CurveComposite* pCrv = CreateBasicCurveComposite() ;
-   pCrv->FromPolyLine( vPL[0]) ;
+   pCrv->FromPolyLine( vMyPL[0]) ;
 
    for ( size_t i = 0 ; i < vPtConvexHull.size() ; i ++) {
       size_t NextIdx = ( i == vPtConvexHull.size() - 1) ? 0 : i + 1 ;
@@ -338,8 +351,12 @@ Triangulate::MakeByDelaunay( const POLYLINEVECTOR& vPL, PNTVECTOR& vPt, INTVECTO
 
   // vertici
    std::vector< Delaunay::Point> vVertex = trGenerator.MyVertexTraverse() ;
-   for ( size_t i = 0 ; i < vVertex.size() ; i ++) 
-      vPt.push_back( Point3d( vVertex[i][0],  vVertex[i][1])) ; 
+   for (size_t i = 0; i < vVertex.size(); i++) {
+      Point3d pt( vVertex[i][0],  vVertex[i][1]) ;
+      pt.ToGlob( frLoc) ;
+      vPt.push_back( pt) ;
+   }
+       
   // triangoli
    vTr = trGenerator.MyTriangleTraverse() ;