~tb + 1. And I'd like to point out the irony here... snowboard manufacturers have been advertising sidecut radius (or equivalent) since about 1990, iirc. It wasn't until relatively recently that sidecut radius would be published by ski companies, printed on skis, or mentioned in ski magazine reviews. At the same time, snowboard racers have gone back to simply referring to a sidecut as "PGS" or "SL", and the numbers are back to being secret. Ha.
Well when you consider that a traditional radial sidecut ceases to be radial when it is up on edge, the door is open to lots of different shapes.