What a good idea it would be if hamburgers and ears of corn and meatballs and ice cream could fall from the sky at the press of a button on a futuristic gizmo! World hunger would end. Everyone would be happy,

Well, be careful what you wish for. That’s the message of the humorously titled 3-D computer-animated Cloudy With a Chance of Meatballs, about a nerdy young inventor who finally hits the jackpot with a machine that rockets into the clouds and turns water vapor into any food one can imagine. Pizza. Cheeseburgers with lettuce and tomatoes. Bacon and eggs and pancakes with syrup. Even pastrami on rye if you’d like.

Cloudy With a Chance of Meatballs has a lot going for it besides its title — vibrant colors, fast-paced action and, in some theaters, some of the best 3-D animation you’re likely to see.

Yes, the computer-generated characters are stylized and look a little plastic. But then there are such eye-popping moments as a river of food flooding through a town and mowing down everything in its path, or millions of cheeseburgers falling from an enormous purple cloud or a snowstorm of ice cream. Cowriters and codirectors Chris Miller and Phil Lord keep the story of junior inventor Flint Lockwood (voice by Bill Hader) barreling along. Yet the film doesn’t hold up to the promise of its early scenes, dragging out its way to an extremely lively but inevitable ending.

The plot is fairly simple and familiar: The underdog who refuses to give up, tries to win the heart of the girl of his dreams and to finally gain the praise he desperately craves from a father who doesn’t understand him.

Flint has been inventing things since grammar school, but none of his inventions work out quite the way he’d hoped. There are spray-on shoes that unfortunately don’t come off, a “remote-control” TV with legs that carry it over to a person who wishes to change channels –– and then walks right out the door, rat-birds who are a cross between rodent and bird and look like hungry rats that can fly on multicolored parrot wings.

Flint hasn’t given up, however. His latest is a machine that looks like a canister vacuum cleaner and is supposed to turn water into food. Any kind of food you’d like. Rather than feeding millions, however, Flint sees it as a way of saving his island town of Shallow Falls, where the local sardine fishing industry is dying, and of finally winning the respect and pride of his father (James Caan), who runs Tim’s Sardine Bait & Tackle Shop.

Things, as you might guess, again do not go the way Flint had planned, with his food machine invention taking off like a rocket across Shallow Falls, decimating the landscape and terrifying the townspeople. But not for long.

For Flint’s invention, rocketing heavenward and taking root in a cloud bank, begins doing just what Flint had dreamed it would do … and then some, raining down whatever food he orders it to create from the water vapor in the cloud. A TV weather channel intern, Sam Sparks (Anna Faris), who has been sent to Shallow Falls to cover the last-ditch attempt by its ambitious mayor to attract tourists to an amusement park called Sardineland, instead uncovers Flint’s remarkable “ manna-from-heaven” event. Her faith in Flint’s abilities propels him to venture forward in his experiment which grows grandiose in size, like the mountain of golden yellow gelatin he creates one night to please Sam.

But there’s a hitch to the food machine which goes a little haywire and begins mutating its bounty to enormous sizes, sending the now-frantic Flint and his friends on a wild ride into the clouds. Along with Sam and Flint on this dangerous mission are a talking monkey and a blowhard named Baby Brent (Andy Samberg), who is locally famous for being the namesake on a brand of sardines and whose baby picture still graces the cans, although he is now all grown up.

The plot gets overplayed as the film revs up toward what should be a colossal ending, but surprisingly seems instead to peter out. Cloudy With a Chance of Meatballs threatens to overstay its welcome, even at a running time of a little over 80 minutes.

Yet there are wonderful imaginative sights in the film that are delights, such as a tornado of spaghetti, headless chicken carcasses springing to life or Gummi bears on the attack. It’s these things that keep the film rolling along and one glued to the screen, even as you know just where it’s headed.

*** 1/2Cloudy With a Chance of Meatballs

Voices: Bill Hader, Anna Faris, James Caan, Bruce Campbell, Andy Samberg, Mr. T.

Rated: PG, contains cartoon violence, scary images.

mjanuson@projo.com