If we can believe Homer — the poet, not Simpson — the “real” Trojan War lasted 10 years. Troy only seems to take that long.

I put “real” in quotes above because Homer’s Iliad, the inspiration for Troy, was written, or rather chanted, some five centuries after the actual events. That’s plenty of time for (possibly) drab events to be encrusted with myth, intrigue and heroism. So don’t worry, I’m not going to bitch about the lack of “authenticity” in Troy, the Wolfgang Petersen-directed battle-and-beefcake snoozefest. For a movie about one of the few stories it’s accurate to call “epic,” this snores-and-sandals stinker is singularly cramped, uninvolving and uninspiring. It’s not even bad enough to be funny, like portions of Petersen’s The Perfect Storm. And did I mention that it’s looooooong?

Who’s to blame? In cases like this I usually exempt the actors. A job’s a job and they have to earn a living in a tough business, so even the ones in Troy who seem to be slumming (Peter O’Toole as the Trojan king Priam), chewing the scenery (Brian Cox and Brendan Gleeson as Greek brothers and kings Agamemnon and Menelaus) or doing the best they can with a one-dimensional part (Eric Bana as Hector, the good but dull prince of Troy) should get a break. Those clearly out of their depth (ex-model Diane Kreuger as a pretty but insipid Helen and mush-mouthed Garret Hedlund as Achilles’ callow protégé Patroclus) are more to be pitied than censured.

Is Brad Pitt at fault? Sort of. Even big stars don’t often have the combination of juice and control freakiness to truly affect the quality level of the films they’re in. Tom Cruise is the exception that proves the rule, and then only when he’s not working with Steven Spielberg (Spielberg is Mr. Quality Control, even when his films are aimed in the wrong direction). Star/producers (i.e. George Clooney, especially in conjunction with Steven Soderbergh) and comic star/writers (i.e. Mike Myers) have more muscle and therefore more responsibility, but for the other dozen or so stars big enough to rate script approval and their pick of director, their actual control is limited. And that level of stardom is its own gilded trap.

This star problem — drawing power without quality control — is compounded with a budget-busting blockbuster, where the financial expectations are so high that the few stars who can “open” such a big picture tinker with their on-screen persona at their own — and the film’s — risk. So even if Brad Pitt realized how miscast he is as warrior/sorehead Achilles, what could he do? “Hey Wolfgang, I think I’d really do better in a smaller part. I’m just petulant, not noble or tragic. Let’s see: I’m still pretty but I’m getting just a bit too old to play Paris — let Orlando Bloom keep that. Hey! I bet I could have fun as Odysseus, making snarky comments and thinking up the Trojan Horse. I can do comedy — did you see my work in Fight Club and Twelve Monkeys? I could even do Hector, the concerned son/husband/father. I was really good in Seven! Eric Bana can do my part, he’s got great pecs and a nice ass.”

Is screenwriter David Benioff at fault? Of course he should shoulder his share of blame for making such a great story so boring, but he should also be applauded for taking the Greek gods out of the equation. Benioff is right; he’s said in interviews that there’s no way you can have Zeus & Company looking down from Olympus without the movie becoming irredeemably silly, or turning into a late-season episode of “Xena: Warrior Princess.”

What about director Petersen? Gifted but uneven, he made the claustrophobic classic Das Boot (1981), the technically accomplished but underwhelming Perfect Storm (2000) and the trimly entertaining In the Line of Fire (1993). He gets out of the way of good actors (O’Toole here, John Malkovich in Fire) and finds some surprising depth in others (Clint Eastwood in Fire, Mark Wahlberg and Diane Lane in Storm). And he does achieve some nice effects in Troy. In one battle scene, the Trojans pelt the invading Greeks with flaming arrows and then catapult enormous, well, fireballs that send the startled soldiers screaming. And he has one short, silent sequence that any director would be proud to feature in his action-film demo reel. The Trojans believe the Greeks have caught a plague and shipped out. A lone Trojan horseman comes over the crest of a hill to see the Greek fleet far below in a hidden cove. He turns to ride back to the city and warn Troy to beware of Greeks bearing gifts, and is swiftly shot out of the saddle before he can even raise his voice. It’s quick, it’s neat and it encapsulates everything that’s at stake. So if Petersen can do that, how come the rest of the movie smells up the theater?

I blame CGI — computer-generated images. Troy and Van Helsing, another recent disappointment, are loaded with CGIs, the bad cholesterol of today’s filmmaking.

I can hear the arguments now: “CGI is just a tool, it’s not bad in and of itself, how else are you going to create vast armies, rebuild ancient ruins or animate scary monsters? What are you, some kind of Luddite who wants to go back to miniatures, matte painting and stop-motion animation?”

Yes, as my friends and family will attest, I am a technophobe, but no, I’m not calling for a moratorium on CGI, just moderation. It is a tool, sometimes an extremely effective one. That short scene I admired above was only possible because Petersen could show dozens of Greek ships crowded together in the harbor, without having to actually rent boats or build miniatures.

But — and be aware I know very little about how CGI effects actually work — I think overreliance on them presents some serious problems:

1) Actors have nothing and no one to play to/with: This is less of a problem than it seems, or rather it’s so ingrained in the scattered, piecemeal way movies are made that CGI only accentuates the problem. Even on quiet little indie flicks that take place in three tiny rooms, not all the actors who are in the scene are on the set — or even in the same time zone — as the rest. Still, I’m convinced the massive amounts of CGI used in Van Helsing were a big reason for the stiff, poorly timed performances, even from normally reliable actors like Hugh Jackman and Kate Beckinsale. I can just hear director Stephen Sommers: “O.K., Kate, I know there’s no one there, but you’re talking to your brother who has been changed into a werewolf as you’re being attacked by two of Dracula’s three flying brides. Give me fear! Give me compassion! Action!”

2) Just because you can show it doesn’t mean you should show it, or more is really less: As classic creepies like the original black-and-white Cat People (1942) amply demonstrate, what’s unseen can be far scarier than what’s seen. A good deal of that film’s power comes from the fact that the audience NEVER sees the heroine actually change into a killer black cat (it’s all in her imagination — or is it?). CGI has made so many things possible for (relatively) little money that film industry techno-geeks are loading movies with them, turning feature films into FX demo reels rather than forcing the director and screenwriter to be creative with the settings, characters and dialogue to tell their story.

3) Narrative and characters get lost amid the effects: This is a corollary of number 2 and also an unfortunate consequence of the audience’s lost innocence when it comes to the movie business. Just as a film’s pre-release “buzz” and opening-weekend numbers are now part of the audience’s perception of the film (if a film does poorly it must be a poor movie, right?), many of us are more knowledgeable about special effects and how they are achieved. So directors feel free to use lots of CGI without worrying that it will spoil the illusion, because the audience doesn’t have any more illusions. But if we’re focused on the effects — even on how “real” they look — we’re not thinking about the story or the characters.

As a consumer service, I’ve come up with a mathematical formula that may prove useful in gauging the EQQ (Entertainment Quality Quotient) of a given movie, to wit:

EQQ = St + Sc + Sx/CGI x 2h+

Where “CGI” is the percentage of computer-generated imagery (measured either by number of minutes of total screen time when any CGI appears, or area of the screen taken up with CGIs on average throughout the entire film); and “2h+” is a running time of more than two hours. Really and truly, is there so much story to tell that even the most basic movie is 135, 142, 157 minutes long? People have babysitters at home charging by the hour, or they’d like to go to the diner and discuss the movie afterwards without a night out turning into an all-nighter. My boyfriend’s comment after pretty much every movie we see — even Bugs Bunny cartoons — is “It could have been shorter.” He’s right.

Counterbalancing long movies with too much CGI can be:

“St” is a dynamic star. Troy made me appreciate how much Russell Crowe’s onscreen charisma made Gladiator entertaining. I also no longer begrudge Crowe his Oscar, having seen The Insider on DVD. Man he’s a good actor, if not the most pleasant person offscreen, apparently;

“Sc” is a strong script. I realize this is both entirely subjective and often meaningless, since it’s the director who bring the script to life and give it its tone. But it’s equally true that a strong script — however you define it — is a basic building block of any film with a high EQQ. Great directors are great directors not just because they can turn chicken shit into chicken salad but because they choose strong scripts or work with writers to make them strong. And mediocre-to-good directors, i.e. the vast majority, need all the help they can get;

“Sx” is, well, sex. This would seem to help Troy’s EQQ, in which pretty people Brad Pitt, Diane Kreuger, Eric Bana, Orlando Bloom, Saffron Burrows (Andromache, a.k.a. Mrs. Hector) and Rose Byrne (Briseis) all suffer a wide variety of wardrobe malfunctions, but it’s just eye candy. In fact, Troy is like a perverse porno film, with the sexy scenes as mere setups to the real action — killing, mayhem and bloodshed. And since we don’t care about any of the characters, seeing their skin is mere movie-star voyeurism — and again, takes us out of the story.

In case you couldn’t tell, I am biased toward narrative and characters rather than visual sensation for sensation’s sake, which I believe CGI encourages. That’s partly because narrative is comforting and partly because I really believe it’s the most effective way — make that the most human way — for movies to achieve entertainment, emotion and art. CGI should be sprinkled on the movie salad like ground pepper, not ladled on like gloppy, bright-orange, restaurant-“quality” Russian dressing.