diff --git a/EGkSurfBezier.h b/EGkSurfBezier.h
index 12e93f6..d4e0620 100644
--- a/EGkSurfBezier.h
+++ b/EGkSurfBezier.h
@@ -69,6 +69,7 @@ public :                      // IGeoObj
       virtual bool GetControlCurveOnU( int nIndV, PolyLine& plCtrlU) const = 0 ;
       virtual bool GetControlCurveOnV( int nIndU, PolyLine& plCtrlV) const = 0 ;
       virtual const ISurfTriMesh* GetAuxSurf( void) const = 0 ;
+      virtual const ISurfTriMesh* GetAuxSurfRefined( void) const = 0 ;
       virtual ISurfTriMesh* GetApproxSurf( double dTol, double dSideMin = 100 * EPS_SMALL) const = 0 ;
       virtual bool GetLeaves ( std::vector<std::tuple<int, Point3d, Point3d>>& vLeaves) const = 0 ;
       virtual bool GetTriangles2D( std::vector<std::tuple<int,Point3d, Point3d, Point3d>>& vTria2D) const = 0 ;