rem: inline friend bool operator != (const OSGBoxVolume &b1, const OSGBoxVolume &b2)
add: inline friend bool operator != (const BoxVolume &b1, const BoxVolume &b2)
context:   inline friend bool operator != (const OSGBoxVolume &b1, 																  const OSGBoxVolume &b2)		{ return !(b1 == b2); }