diff --git a/EGkBBox3d.h b/EGkBBox3d.h
index b78652b..efe3ee7 100644
--- a/EGkBBox3d.h
+++ b/EGkBBox3d.h
@@ -33,20 +33,25 @@ class EGK_EXPORT BBox3d
       BBox3d( const Point3d ptP)
          : m_ptMin( ptP), m_ptMax( ptP) {}
       BBox3d( const Point3d ptP1, const Point3d ptP2) ;
+      BBox3d( double dX1, double dY1, double dZ1, double dX2, double dY2, double dZ2) ;
       void Reset( void)
               { m_ptMin = Point3d( +INFINITO, +INFINITO, +INFINITO) ;
                 m_ptMax = Point3d( -INFINITO, -INFINITO, -INFINITO) ; }
       void Set( const Point3d ptP)
               { m_ptMin = ptP ; m_ptMax = ptP ; }
       void Set( const Point3d ptP1, const Point3d ptP2) ;
+      void Set( double dX1, double dY1, double dZ1, double dX2, double dY2, double dZ2) ;
 
    public :
+      bool IsEmpty( void) const
+              { return ( ! IsValid()) ; }
       void Add( const Point3d& ptP) ;
       void Add( const BBox3d& b3B) ;
       void Expand( double dDelta) ;
       void Expand( double dDeltaX, double dDeltaY, double dDeltaZ) ;
       bool GetMinMax( Point3d& ptMin, Point3d& ptMax) const ;
       bool GetCenterExtent( Point3d& ptCenter, Vector3d& vtExtent) const ;
+      bool GetCenter( Point3d& ptCenter) const ;
       bool ToGlob( const Frame3d& frRef) ;
       bool ToLoc( const Frame3d& frRef) ;
       bool Encloses( const Point3d& ptP) const ;
diff --git a/EGkVector3d.h b/EGkVector3d.h
index 2b1b8d1..9d14ca2 100644
--- a/EGkVector3d.h
+++ b/EGkVector3d.h
@@ -14,6 +14,7 @@
 #pragma once
 
 #include "/EgtDev/Include/EGkGeoConst.h"
+#include <math.h>
 
 //----------------------- Macro per import/export -----------------------------
 #undef EGK_EXPORT