This new Disney computer-animated movie makes use of the same 3-D process that was employed for the first time in “Chicken Little.” Unfortunately, in anything but purely visual terms it’s a hit-and-miss proposition, not tediously ordinary like its predecessor but too often mistaking mania for amusement.

To deal with appearances first, though the actual look of the picture isn’t anything remarkable, the 3-D effect is excellent, and if you’re going to arrange a family outing to see “Meet the Robinsons,” you should definitely search out a theatre showing it in that format. (It’s preceded by a 1953 Donald Duck cartoon retooled for the process, which looks great, too.) But although the script is credited to no fewer than seven writers—or perhaps because of it—the movie mixes some nifty touches with others that are simply frantic and unfunny. And, unfortunately, the latter predominate.

It begins with Lewis (voiced jointly by Daniel Hansen and Jordan Fry), an orphan whose obsession with inventing things always turns off potential adoptive parents. (It also annoys his roommate, a sad-sack little tyke named Michael “Goob” Yagoobian, voiced by Matthew Josten.) At a science fair where his latest contraption—designed to retrieve memories so that he can recall his mother—predictably fails, there appear two strange visitors.

One is a pushy, hyperactive boy named—in what’s surely a nod to the old “Lost in Space” television series—Wilbur Robinson (Wesley Singerman), who claims to be from the future and who urges Lewis not to give up on his machine, even though its malfunction was engineered by an even odder fellow, called the Bowler Hat Guy (Stephen John Anderson, the director and co-writer). Before long Wilbur whisks Lewis off to the future to save his world. There he meets the wacky Robinson clan, a vast brood that includes mom Franny (Nicole Sullivan), who spends her time conducting a chorus of singing frogs; granddad Bud (Stephen John Anderson), an old duffer involved in all sorts of goofiness; Uncle Art (Adam West), a pizza delivery guy who dresses like a superhero; silent, obese Uncle Joe, the ultimate couch potato (to name only a few); and their fast-talking, stretchable family robot Carl (Harland Williams). Lewis and Wilbur must also defeat the machinations of Bowler Hat Guy, who, it turns out, is from the future too and, under the influence of his hat, a powerful machine that can extend metal legs and totter about to cause all sorts of mischief, wants to use Lewis’ memory invention to alter his world in a most unpleasant way. Though the movie never really makes clear how that’s supposed to happen, in the process Bowler Hat fashions some menaces for the boys to overcome, like a T-Rex from the prehistoric era. Ultimately the interrelationships among all the character are revealed and Lewis learns the great lesson the Robinsons have to impart—which is “Keep On Moving,” whatever failures might fall your way. And from what we see in an extended coda, Lewis obviously takes the message to heart.

Unfortunately, he’s one of the picture’s main problems. Frankly, Lewis is a drip—and he’s irritatingly matched with the aggressive Wilbur, who’s as dully stereotypical in his way as Lewis is in his. But they’re literally small potatoes compared to the Robinson clan, each of whom is supposed to be crazily lovable but comes across as merely crazy instead. They prove a boringly exhausting group as they pop up like inmates at an asylum to do their wacky bits of surrealistic nonsense before receding back into the chorus line as another member of the family steps out for his solo. The bizarrely pointless nature of their oddities—combined with the frantic chase sequences as Lewis and Wilbur deal with the dangers unleashed upon them—make most of the “future” parts of the movie pretty much a mess.

On the other hand, there’s at least a smidgen of smarts about the villainous Bowler Hat Guy, who’s given an almost Victorian-era look, even if most of his dialogue (he has a habit of talking to himself) is pretty lame. And the creepy hat itself makes a good impression, too. But even better is young Michael, an almost preternaturally depressed kid who’s easily the most memorable character in sight: he may be slow-moving and sad, but he’s a lot more fun to watch than the wild-eyed Robinsons. There’s also an amusing girl at Lewis’ science fair who looks as though she might have stepped out of “The Addams Family,” but she’s dispensed with in a breeze. Too bad.

The visuals in “Meet the Robinsons” aren’t that great—they look rather like something derived from “Jimmy Neutron,” with the overbroad character animation oddly matched with nondescript backgrounds. But the 3-D effect makes them more attractive than they actually are. (Another reason to seek out a venue with that format. The plastic glasses required are light and comfortable even for somebody who has to put them over ordinary specs.) In terms of content, though, the movie is mediocre—an overly busy adventure with far too many annoying characters, an army of mixed messages and more schmaltz than heart. And a few original songs by Rufus Wainwright, all of them instantly forgettable, don’t help matters. Even if you look forward to meeting the Robinsons, after ninety minutes you’ll probably be happy to take your leave of them.