diff --git a/CurveArc.cpp b/CurveArc.cpp
index c872577..2f78bbb 100644
--- a/CurveArc.cpp
+++ b/CurveArc.cpp
@@ -727,7 +727,11 @@ CurveArc::GetBBox( const Frame3d& frRef, BBox3d& b3Ref, int nFlag) const
       return false ;
   // assegno il box nel riferimento
    b3Ref.Reset() ;
-   ArcApproxer aAppr( LIN_TOL_APPROX, ANG_TOL_APPROX_DEG, false, *this) ;
+   double dLinTol = LIN_TOL_APPROX ;
+   double dAngTolDeg = ANG_TOL_APPROX_DEG ;
+   if ( ( nFlag & BBF_EXACT) != 0)
+      dLinTol = LIN_TOL_MIN ;
+   ArcApproxer aAppr( dLinTol, dAngTolDeg, false, *this) ;
    double  dU ;
    Point3d ptPos ;
    while ( aAppr.GetPoint( dU, ptPos)) {
diff --git a/EgtGeomKernel.rc b/EgtGeomKernel.rc
index a3ec081..379f8cd 100644
Binary files a/EgtGeomKernel.rc and b/EgtGeomKernel.rc differ