Desperate neither to declare the wonderments of digital 3-D nor to debunk them, Martin Scorsese’s “Hugo” does have some preaching to do, on the director’s pet subject of film preservation. Magnanimously, Scorsese won’t say outright that today’s algorithm-rendered pseudo-epics have nothing on the blood, sweat and practical effects of the very old school. It’s all of a piece, he suggests, and ain’t it grand?

Some of it, sure. With its saucer-eyed faces, its jumpy camera zips, and its Paris “of old,” “Hugo” presents itself at first like some overwrought steampunk confection a la “Amélie.” Or, more currently, like a weird segue between the new “Sherlock Holmes” movie and Spielberg’s “Tintin.” How necessary this seems will be in the eye of the beholder.

Hugo (Asa Butterfield) is a watchful orphan living by his wits in the Paris train station whose clocks he maintains. When not dodging an odd, increasingly Peter Sellersish, orphan-hunting cop (Sacha Baron Cohen), he’s swiping occasional croissants and the spare parts necessary to fix a wind-up mechanical man inherited from his dear departed watchmaker father (Jude Law).

The automaton looks like something out of Lang’s “Metropolis,” and in its deadpan way has one of the movie’s most expressive faces. It’s also Hugo’s connection to the embittered proprietor of the train-station toy shop (Ben Kingsley), who won’t let his adopted daughter (Chloë Grace Moretz) see movies because he used to make them and now can’t bear to revisit that past. Turns out he’s the early cinema pioneer Georges Méliès, whose 1902 movie “A Trip to the Moon” was among the first to see the medium’s potential as cutting-edge magic act. But the world seems not to want this “Papa Georges” anymore, and so the boy also must try his hand at fixing the old man’s broken spirit.

Thus, in spite of Butterfield’s quite clever performance, does he also become a cog in Scorsese’s film-history-appreciation machine. Sometimes literally: Having taken pains to remind us that silent-comedy maestro Harold Lloyd once dangled from the hands of a big city clock, Scorsese takes further pains to have Hugo dangle from the hands of a big city clock. It’s about as thrilling as a thank-you note.

“Time hasn’t been kind to old movies,” someone says, and suddenly it feels like we’ve been watching this on public TV, with our station hosts politely breaking in to ask at length for donations. Good thing, then, that flashbacks to an inspired young Méliès at work have all the vigor and momentum of Scorsese’s best stuff. So much, actually, that it almost backfires: Screw Hugo, we might think, let’s stay with this guy. (Kingsley is expectedly great.)

No can do: “Hugo” derives from writer-illustrator Brian Selznick’s Caldecott Medal-winning children’s book, “The Invention of Hugo Cabret.” Screenwriter John Logan shares Scorsese’s evident enthusiasm for the material, and it’s as good a try for holiday-glazed, calculatedly timeless family entertainment as this movie-mad filmmaker could hope for.

Not being above gimmickry for its own sake is part of this picture’s charm, and its point. As a blessing, it’s mixed. Too much of the “Hugo” machinery seems false, both computery and emotionally cloying. Too much of the technique is self-impeding. For instance, Scorsese’s well established knack for appropriating pre-existing music — in this case, by Erik Satie — obviates Howard Shore’s humdrum score, but guess which composer’s work we hear more often? And although it is sentimentally satisfying, this narrative gearbox needs too much winding up.

“Hugo” is a kitschy, self-enclosed curio, like some great big cinematic snow globe complete with atmosphere so moist and particle-flecked that just the thought of inhaling it feels a little suffocating. It may yet inspire future generations — of art directors and production designers, at least — but in the meantime remains gleefully preoccupied with commemorating past glories.