The third installment in Disney’s lucrative urban dance flick franchise mostly delivers the guilty-pleasure goods. And for a welcome change of pace, the 3-D doesn’t seem like just a cynical ruse to bilk gullible teens out of a few extra bucks of allowance money. Give returning director Jon M. Chu his due. Unlike most so-called dance movies these days, Chu actually films his performers in full body shots (most of the time anyway), so we can see they’re really dancing. I know this probably sounds like a small thing, but most contemporary dance flicks tend to obscure their hoofers’ lack of experience, grace and, talent with choppy, headache-inducing MTV editing. The cookie-cutter storyline and archetypal characters remain pretty much the same as in the previous Step Up movies. Sharni Vinson stars as dance-addled, hot-to-trot ingénue Natalie, Rick Malambri plays rakish boho-impressario Luke, and the whole thing builds to a big dance showdown in which Luke’s pure-of-heart Pirates crew battles the boo-hiss Samurai posse. Shake your booty indeed.