`STORM' TROUPERS SPECIAL EFFECTS GENIUSES MASTER WAVES OF THE FUTURE.

Byline: Bob Strauss Film Writer

For a slam-bang movie thrill ride, there's nothing like the science of fluid dynamics.

Really. We're not kidding.

In order to film ``The Perfect Storm,'' Sebastian Junger's best- selling, non-fiction account of the 1991 mother of all weather systems and the Massachusetts fishermen who never returned from it, water the likes of which has never before been seen in cinema - raging chop, withering spray, ocean swell the size of mountains - had to be created.

And lots of it. Something like half of the film's running time is set at sea during the storm of the century, when a hurricane, an arctic front and a third weather system collided in the North Atlantic. And director Wolfgang Petersen wanted it all to look convincing and relentlessly terrifying, all the time.

``This is a great, extreme story of man against nature with 100-foot waves, awesome dimensions,'' explains Petersen, who has made the above-average action thrillers ``In the Line of Fire'' and ``Air Force One'' and, in his native Germany, ``Das Boot,'' which is widely considered one of the best submarine movies of all time. ``But, how to put that on the screen? It's fairly easy to write about it, but how to visualize that in a way a sophisticated audience of 2,000 would go for the ride and believe it. If it works, it would be so visceral and in-your-face frightening that it would almost be hard to sit through it.

``And that was the goal,'' Petersen adds. ``What we wanted right from the very beginning was to take an audience to a place where they have never really been before and experience something that they've never experienced before. That included myself; I've never really been in a situation like that, and nobody who has is here anymore to tell the tale. Thank God, with the filmmaking tools that we have these days, you can go there. It's far beyond what I could do in 'Das Boot' 19 years ago.''

Easy for the director to say, since he certainly wasn't going to take camera boats out in gale conditions to capture the necessary footage (in fact, Petersen reports that shooting non-storm ocean scenes off of Dana Point and the lost fishermen's home port of Gloucester, Mass., was a nightmare of composition-wrecking crosscurrents and mass seasickness). The really heavy water, more than 300 shots' worth, had to be carried digitally.

Which would be a lot of busy work, no doubt, but otherwise shouldn't be a problem. After all, outfits like Industrial Light & Magic had been creating convincing, computer graphic dinosaurs, meteors, tornadoes and the like for years.

How tough could a little water - OK, a lot of water - be?

``This was the hardest project I've ever done,'' confesses Stefen Fangmeier, the ILM visual effects supervisor of such CG benchmarks as ``Twister,'' ``Speed 2'' and ``Saving Private Ryan.'' ``You know, you can make one shot beautiful, but the important thing here was to provide a consistent quality, make all 338 look great. And there was not only the volume of stuff, but how long it would take to get it right. The feedback is very slow when you have to use these very computation-intensive systems. You'd do a simulation of a wave crest; then it would take two hours before you could look at it and if it didn't look right, then it takes another two hours to try to fix it.

``And you had to really nail it pretty close. If any of the water or boat or wind movement or density was 5 percent off - a little too fast, a little too slow, a little too thick, a little too clumpy, a little too much reflection - it looked wrong. There was little margin for error; either you get it or you just struggle forever.''

But it's only water. How can water be so complicated? I mean, everybody knows what water looks like ...

Oh, I see.

``People are pretty good at looking at water and knowing when it's wrong,'' ILM's John Anderson notes. ``They're not very good at telling you what's wrong about it, but they can tell you that it's not right.''

Anderson, a former University of Wisconsin atmospheric and oceanic sciences professor, is ILM's resident - yes - fluid dynamics expert. His team was responsible for simulating the underlying movement of ``Perfect Storm's'' roiling seas to a persuasive T. But the key word there is ``persuasive''; for all the hard science and realistic detail that had to inform the watery computer graphics, an extra, less-quantifiable factor had to be figured in as well.

``In the past, when we've done shows with waves like 'Deep Impact,' we've hand-animated the bulk of the wave, then procedurally put texturing and splashes and stuff on top of it,'' Anderson explains. ``For this movie, both because of the number of shots and because it's a photo-real movie of something that really happened as opposed to a giant comet or something, we wanted to have as much of that intrinsic rightness, in terms of how the water moves, as possible. To the extent that we could, we wanted to start with something close to physically correct wave fields.

``But that doesn't mean that we weren't trying to achieve performances,'' Anderson adds. ``A number of times, we'd go back and modify a simulation to get a performance, but we tried to keep the physics during the shot right if we could do that.''

Or, as Fangmeier puts it, ``We're not making a documentary here. As long as it looks real and feels right ... and scientific reality doesn't always feel right.''

Still, what Anderson's team had to perfect on a macro level, the 100-plus digital artists Fangmeier oversaw had to render in maddeningly precise detail.

``Waves, at their surface, have a lot of sudden movement on them,'' Fangmeier notes. ``It was important to get all of those right, especially relative to a 70-foot boat, to give it a sense of scale (a lot of times, the boat would look too modelly or small). But really, the hardest thing was the white stuff on the water. That is really the character of the storm, the indicator of how rough it is. Foam, wave crests, splash ripping off from the waves is what really gives you the sense that there's this ferocious storm and great wind going on. Creating all of that stuff on the water, then adding in boat wakes with their own foam structures, was quite a technical challenge to deal with.

``Stuff gets windblown, collides with the boat, splashes off of it, mixes in with other water movement - all of these things are very naturally interrelated, but because of complexity issues with our computations, we had to deal with them all as separate elements.''

And that's just inside computers. Though many of the storm shots featured a CG fishing boat, helicopter, Coast Guard cutter, sailboat and/or human figures, numerous shots were also composited with live elements.

George Clooney, Mark Wahlberg and the other actors playing the doomed crew worked primarily on a life-size replica of the missing swordfisher, the Andrea Gail, which was connected to a gimbal in a 95-foot-square, 20-foot-deep water tank on a Warner Bros.' soundstage. The blue screen-surrounded facility was also equipped with wind machines, rain towers and water cannon that spread buckets of wet stuff all over the frame.

Surprisingly enough, this chaotic practical water ballet was relatively easy for the CG artists to match.

``There are a lot of shots that blend actual guys in the water with our CG water,'' Fangmeier says. ``But what actually helped in that process was that the tank water reflected the blue screens, which made it easier to find the right places to blend our CG water into that.''

A rare technical nicety in this work-intensive struggle. Of course, the actors and stuntmen who worked the tank shots had it a little less cushy.

``Talk about a film that was a physical challenge of enormous proportions, it was `Perfect Storm,' '' director Petersen marvels. ``I told these guys that it would be really bad if they just came off as Hollywood actors pretending to be fishermen. We wanted to create a total reality, which meant that with the dump tanks and the wind machines and rocking gimbal, they would go through hell. It was unbelievably tough; the water threw them all over the boat.

``But they all seemed excited by it,'' Petersen observes. ``That's because, basically, actors like it very much if they get a chance to prove themselves, that in a physical sense they are up to the task.''

Whether audiences will be able to take the just-this-side-of-physical pounding ``The Perfect Storm'' will put them through remains to be seen. But whether they like it or not, the breakthrough aspect of this cinematic sea saga cannot be denied.

``We really created water without restraint,'' Fangmeier says proudly. ``There was nothing Wolfgang asked for that we said we couldn't do. The boat rolls, the boat flips over, there was nothing we couldn't have in the movie. When you give a filmmaker an ocean and can say, 'Do whatever you want,' that's great.''

CAPTION(S):

4 photos

Photo: (1 -- cover -- color) George Clooney in the "The Perfect Storm"

(2 -- 3) The Andrea Gail faces the forces of nature during ``The Perfect Storm,'' while George Clooney struggles to keep the boat steady as members of his crew reach out to render aid to their shipmates.

(4) Mark Wahlberg, left, and George Clooney brace themselves for the onslaught of a huge wave in ``The Perfect Storm.''