This season, Teton Gravity Research celebrates 30 years of filmmaking with “Pressure Drop” at the Vilar Performing Arts Center on Oct. 3. “Pressure Drop” portrays “that fleeting space between calm and chaos …” when the mountain demands all of your energy, attention and physicality. Like every TGR film, this one features an abundance of big mountain lines, huge flips and a couple of crashes. Skiing isn’t the only thing highlighted in this 30th anniversary film by TGR, snowmobiling gets the spotlight, too. Teton Gravity Research/Courtesy photoThough it’s called “Pressure Drop,” there are some silly, playful scenes, particularly one involving a snowman and athletes bouncing off tree trunks.