As “Super Troopers 3” opens in theaters this weekend, audiences at the Greenfield Garden Cinemas will have a chance to hear behind-the-scenes stories from Ashfield native Tony Scelsi, who served as the film’s second second assistant director. Scelsi, who now lives in Greenfield, began working on the franchise as a production assistant on “Super Troopers 2” before advancing to second second assistant director on the third film. “It’s one more that when the director is also starring in the film,” Scelsi said. Scelsi said that for smaller, independent films such as “Super Troopers 3,” the time spent shooting the film isn’t as long as so people may think. While larger-budget productions can spend nearly six months filming, “Super Troopers 3” wrapped in just 28 days, including only 20 shooting days.