code: public void notifyModified(int flags) {
  		if (flags == DirtyFlags.DirtyAll) {
  			m_reservedPointCount = -1;// forget the reserved point number
  			_notifyModifiedAllImpl();
  		}
  		m_flagsMask |= flags;
  
  		_clearAccelerators();
  		_touch();
  	}
docs: Notifies the Geometry of changes made to the vertices so that it could
  reset cached structures.