diff --git a/PolyArc.cpp b/PolyArc.cpp
index 603a162..7d0eeca 100644
--- a/PolyArc.cpp
+++ b/PolyArc.cpp
@@ -15,6 +15,7 @@
 #include "stdafx.h"
 #include "DistPointLine.h"
 #include "GeoConst.h"
+#include "CurveArc.h"
 #include "/EgtDev/Include/EGkPolyArc.h"
 #include "/EgtDev/Include/EGkFrame3d.h"
 #include <algorithm>
@@ -344,6 +345,94 @@ PolyArc::IsClosed( void) const
    return ( AreSamePointApprox( m_lUPointBs.front().ptP, m_lUPointBs.back().ptP)) ; 
 }
 
+//----------------------------------------------------------------------------
+bool
+PolyArc::IsRectangleXY( BBox3d& b3Rect) const
+{
+   b3Rect.Reset() ;
+  // Deve essere chiusa
+   if ( ! IsClosed())
+      return false ;
+  // Verifico presenza di archi e linee oblique e calcolo il box
+   Point3d ptIni, ptFin ; double dBulge ;
+   bool bNext = GetFirstArc( ptIni, ptFin, dBulge) ;
+   while ( bNext) {
+     // non sono ammessi archi
+      double dLeftDeflection = - dBulge * DistXY( ptIni, ptFin) / 2 ;
+      if ( abs( dLeftDeflection) > 10 * EPS_SMALL)
+         return false ;
+     // non sono ammesse linee oblique
+      if ( abs( ptFin.y - ptIni.y) > 10 * EPS_SMALL  &&  abs( ptFin.x - ptIni.x) > 10 * EPS_SMALL)
+         return false ;
+     // la Z deve essere costante
+      if ( abs( ptFin.z - ptIni.z) > 10 * EPS_SMALL)
+         return false ;
+      // aggiorno il box
+      b3Rect.Add( ptIni) ;
+      b3Rect.Add( ptFin) ;
+     // passo alla curva successiva
+      bNext = GetNextArc( ptIni, ptFin, dBulge) ;
+   }
+  // Verifico che tutte le linee stiano sulla frontiera del box
+   bNext = GetFirstArc( ptIni, ptFin, dBulge) ;
+   while ( bNext) {
+     // verifico che l'inizio stia sulla frontiera del rettangolo
+      if ( abs( ptIni.x - b3Rect.GetMin().x) >  10 * EPS_SMALL  &&  abs( ptIni.x - b3Rect.GetMax().x) >  10 * EPS_SMALL  &&
+         abs( ptIni.y - b3Rect.GetMin().y) >  10 * EPS_SMALL  &&  abs( ptIni.y - b3Rect.GetMax().y) >  10 * EPS_SMALL)
+         return false ;
+     // verifico che la fine stia sulla frontiera del rettangolo
+      if ( abs( ptFin.x - b3Rect.GetMin().x) >  10 * EPS_SMALL  &&  abs( ptFin.x - b3Rect.GetMax().x) >  10 * EPS_SMALL  &&
+         abs( ptFin.y - b3Rect.GetMin().y) >  10 * EPS_SMALL  &&  abs( ptFin.y - b3Rect.GetMax().y) >  10 * EPS_SMALL)
+         return false ;
+     // passo alla curva successiva
+      bNext = GetNextArc( ptIni, ptFin, dBulge) ;
+   }
+   return true ;
+}
+
+//----------------------------------------------------------------------------
+bool
+PolyArc::IsCircle( double dLinTol, Point3d& ptCen, Vector3d& vtN, double& dRad, bool& bCCW) const
+{
+  // Deve essere chiusa
+   if ( ! IsClosed())
+      return false ;
+  // Devono essere presenti solo archi con lo stesso centro, raggio e direzione
+   bool bFirst = true ;
+   Point3d ptIni, ptFin ; double dBulge ;
+   bool bNext = GetFirstArc( ptIni, ptFin, dBulge) ;
+   while ( bNext) {
+     // non ammessi segmenti di retta
+      double dLeftDeflection = - dBulge * DistXY( ptIni, ptFin) / 2 ;
+      if ( abs( dLeftDeflection) < 10 * EPS_SMALL)
+         return false ;
+     // calcolo l'arco
+      CurveArc cArc ;
+      if ( ! cArc.Set2PNB( ptIni, ptFin, m_vtExtr, dBulge))
+         return false ;
+      if ( bFirst) {
+         bFirst = false ;
+         ptCen = cArc.GetCenter() ;
+         vtN = cArc.GetNormVersor() ;
+         dRad = cArc.GetRadius() ;
+         bCCW = ( cArc.GetAngCenter() > 0) ;
+      }
+      else {
+         if ( ! AreSamePointEpsilon( ptCen, cArc.GetCenter(), dLinTol))
+            return false ;
+         if ( ! AreSameVectorApprox( vtN, cArc.GetNormVersor()))
+            return false ;
+         if ( abs( dRad - cArc.GetRadius()) > dLinTol)
+            return false ;
+         if ( bCCW != ( cArc.GetAngCenter() > 0))
+            return false ;
+      }
+     // passo alla curva successiva
+      bNext = GetNextArc( ptIni, ptFin, dBulge) ;
+   }
+   return true ;
+}
+
 //----------------------------------------------------------------------------
 bool
 PolyArc::GetFirstUPoint( double* pdPar, Point3d* pptP, double* pdBulge, bool bNotLast) const