Ipanema, here she comes. Diane von Furstenberg sent her girls packing to Brazil and neighboring lands — “from disco in Rio to polo in Argentina” — in a collection that was fun, feisty and oh so hot, occasionally too much so. She cut her dresses short and sensual, some with one shoulder, and kept to a party palette of tropical hues. Polkadots were a recurring motif, rendered in oversize prints and shimmying confetti paillettes. And in keeping with her “la petite valise” approach, she offered some appealing items — a boyish slouchy T-shirt, a sweet eyelet top and an arty paint-splattered jean. It was a spirited Rio romp, only lacking caipirinhas and a cabana boy or two.