Bobcat Goldthwait’s comedy can be dark, but beneath the antic exterior he’s got a good heart. That explains why he’s in town shooting a documentary about his longtime friend and fellow comedian Barry Crimmins. “I’ve basically known Barry all my life,” Bobcat told us Tuesday. “I think he’s a brilliant satirist, and my goal with this movie is to expose him to a larger audience.” Wednesday, Goldthwait (inset) will film Crimmins onstage at the Comedy Studio, a space he helped create above the Hong Kong Restaurant in Cambridge. Already in the can are interviews with an impressive collection of comics who credit Crimmins as an early influence, including David Cross, Steven Wright, Marc Maron, Lenny Clarke, Jimmy Tingle, Tony V, and Steve Sweeney . “It’s kind of a heartfelt story because it will also deal with [Crimmins] working through abuse he suffered as a child and getting through to the other side,” said Goldthwait. “It’s an inspirational story about an inspirational guy.” Crimmins, who grew up in upstate New York, is perhaps best known for booking Boston’s best and brightest wits at the Ding Ho, a Chinese restaurant in Inman Square, in the 1970s. He later focused on performing, getting a lot of attention for his political satire.