GREAT BARRINGTON â âHe doesnât think like we do. Heâs a mechanical engineer,â playwright Mark St. Germainâs brother Paul says to him of their father, Louis St. Germain, in St. Germainâs fitful, less-than-satisfying autobiographical memory play, âDad.â âTheyâre all about precision; getting things right. Measurements. Blueprints. Otherwise, the world doesnât make sense. He needs answers.â So does his playwright son, Mark, played by an uncharacteristically hard-working Mark H. Dold in the Great Barrington Public Theater production that opened over the weekend in the Daniel Arts Center at Bard College at Simonâs Rock, where it is scheduled to run through Saturday evening.