[Freesurfer] Creating a distance scale bar for a pial surface-render viewed in tksurfer

I was wondering if freesurfer has a way of generating a scale for distance, similar to what one would see in the legend of a roadmap. I'm thinking of using such a scale for a 3-d pial surface-render of an averaged brain (as generated using make_average_surface). Since it's a 3-d image, I had in mind a sort of 3D Cartesian coordinate scale, with scale bars for the x, y, and z directions. Does freesurfer have some visual representation of a distance scale like I've described, or perhaps some alternative?

Eric Moulton PhD Assistant Neuroscientist P.A.I.N. Group Brain Imaging Center McLean Hospital 115 Mill Street Belmont, MA 02478 Phone: 617-855-2604 Fax: 617-855-3772