Ryan McGinley has taken another batch of nubile young things on a three-month road trip across big-sky America and photographed them in the buff, communing with nature. An annual event, the group this time crisscrossed through 30 states, where McGinley’s chosen non-models — artists, musicians, dancers, poets — frolicked in fields, explored caves, built campfires, and looked longingly at the nighttime sky in apparent existential self-reflection. The new works, part of Art Basel Hong Kong, are on view at the Galerie Perrotin gallery in an exhibition called, in rather hippie-like terms, Vertical Color of Sound.