assuming the usual FX vol surface conventions are correctly set for the given market: how do I extract the 3D Bloomberg implied vol surface. I understand that the data from their implied vol table form the basis of our interpolation and that you can export to Excel. However, I would like to fit the implied vol surface and see how different methods behave relative to Bloomberg or Murex's surface - is there a standard way of checking this beyond evaluating the implied vol surface at multiple point