the relax in zbrush does a sort of relax but keeping volume somehow. I wonder if a maxscript relax could be made which relqaxes each vert then push back along vertex normal by some factor to restore somewhat the volume. This may not be the solution for this particular problem but It's got me thinking! :D
What about Set Flow under graphite>loops>set flow (edge sub-object mode)?..usually it'll give a nice smooth result (you can press it a few times to get more relaxed edge flow, it's not gonna make it flat like what relax will do). _Revel
Relax is nice if you want the surface to be FLAT flat, like on a side body panel. Around curves, you'll probably want the vert-by-vert method, although there's some sweet Maxscripts for speeding this up a bit. Check out: http://www.scriptspot.com/3ds-max/scripts/straighten-edge . To use that one, I'd do a loop…