Judd Apatow rules the movie comedy universe at this point, and Kevin Smith knows it. The writer-director’s latest is a carefully calculated bit of artistic mooching in which he attempts the balancing act of appropriating elements of the Apatow canon while appearing not to pay homage to it.

Consider that Apatow hits such as The 40 Year Old Virgin, Knocked Up and Superbad derive a good deal of their humor from dialogue on the subject of porn. They’re love stories disguised as raunchfests and feature a rotation of regulars including Seth Rogen, Elizabeth Banks, Gerry Bednob and Craig Robinson. As it happens, all three of these things are also true of Zack and Miri Make a Porno. Smith’s one twist on the Apatow formula? Porn isn’t just discussed. It’s produced. Sort of.

Rogen and Banks play longtime friends who share a shabby Pittsburgh apartment. One day it occurs to them that trouble may be looming as a result of their failure to pay rent or utility bills for several months. It’s unclear why two neurotypically developed people pushing 30 wouldn’t know better — or where the money is going instead. Both roommates have jobs, and neither appears to have a secret drug or gambling problem. So when their heat, water and power are shut off, it comes across less as a believable inconvenience than as a sloppily contrived plot point.

Not to mention that this happens to take place on the evening of Zack and Miri’s 10th high school reunion. What are the odds? They decide to attend anyway — a choice that proves fortuitous for the viewer, as the sequence features the savviest casting and biggest laughs of the entire film. Brandon (Superman) Routh and Justin Long make brief appearances. Routh was the class hunk and star jock, so the big joke is he’s gay. The much funnier joke is that his boyfriend, Long, is a dude-on-dude porn star who consumes one margarita too many and feels compelled to shout the truth about their love to the rafters. The public spat that ensues is priceless.

The evening proves fortuitous for Zack, too, as his close encounter of the X-rated kind leads him to conclude that the solution to his financial woes lies in homemade adult entertainment. His thinking is that if he and Miri make a pornographic movie, at the very least everybody in their graduating class will be likely to buy a copy, and that cash alone will get them out of debt and then some.

Again, a somewhat contrived plot point — but, hey, look at the title. Whether the reasons for doing so are credible or not, somebody’s got to make a porno here. Banks goes along with the plan because the two are such close friends and have seen each other naked countless times already. Robinson plays a henpecked husband who works alongside Rogen in a Starbucks-styled coffeeshop. He agrees to put up the money in exchange for the title of producer and the chance to audition scantily clad female talent.

Eventually a crew is assembled (Clerks’ Jeff Anderson comes on as director of photography), and a cast is chosen (Jason Mewes of “Jay” fame — sans Silent Bob — plays Lester, a heavily tattooed chap hired for his ability to achieve instant erections). Real-life porn vets Katie Morgan and Traci Lords round out the lineup. Zack decides to shoot at the coffeeshop after hours, a location choice that does make for one gut-busting scene when the door is left unlocked and a customer in search of java wanders in to discover something considerably steamier brewing.

But I must say that the most shocking thing about Smith’s latest, in the end, is just how shocking it’s not. Yes, it’s as potty-mouthed a picture as you’re likely to see, but that’s the thing: For a movie originally rated NC-17, it’s all talk and very little action. Not that I was eager to drink in the spectacle of Rogen going all John Holmes, mind you. It’s simply that the title’s a total tease. Again and again, the filmmaker threatens to push the envelope, only to pull back and retreat into conventional romantic comedy territory.

Despite all the naughty dialogue, this is fundamentally a story that wouldn’t look out of place on TLC, a theoretically touching tale of two friends slowly realizing they were meant to be something more. The further into the film Smith gets, the less he focuses on the porno and the more he plays matchmaker for Zack and Miri. Meanwhile, he displays none of Apatow’s knack for interweaving raunch and romance, so the final third of the movie feels like it was transported from a completely different picture.

Rogen and Banks are, of course, two of the most likable screen presences out there, but they aren’t enough to elevate the film beyond the level of gratuitously gutter-mouthed Apatow knockoff. The bottom line: Zack and Miri make a porno. Kevin Smith makes the most derivative, disappointing picture of his career.