From Wired, here's a pre-making-of article about the upcoming sequel, The Matrix Reloaded.

It's a hell of a funny, cool, and just a little bit scary article.

On the centerpiece fight scene of the film:

As the team tossed ideas around for one hellacious fight scene that became known in-house as the Burly Brawl, Gaeta realized that the innovative technology he and his crew developed for The Matrix's ultra slo-mo action sequences would not be sufficient to bring the Wachowskis' new vision to the screen. Those oft-imitated shots - now universally known as Bullet Time - required serpentine arrays of meticulously aligned cameras, and months of planning, for a brief scene featuring two or three actors. In the Burly Brawl, super-Neo would battle more than 100 Agent Smiths in an extended orgy of kung fu orchestrated by crack martial-arts choreographer Yuen Woo-Ping.

and...

If the dojo fight in The Matrix was a kung fu sonata, the Burly Brawl is a symphony. Neo tears the sign from the ground and wields it as a kendo sword, vaulting pole, and battering ram. A woman walking by can't believe what she's seeing; suddenly her body is hijacked, she drops her grocery bag, and another Smith charges into the fray. Whole battalions of Smiths arrive, mount assaults, attack in waves, scatter, regroup, and head back for more. (At ESC, one massive pile-on was dubbed the "Did someone drop a quarter?" shot.) In the thick of it, Neo is dancing, chucking black-tied bodies skyward, pivoting around the signpost, and using shoulders as stepping-stones over the raging river of whup-ass.

Heh.

How're they gonna do it? Why, invent new special effects:

Gaeta found the answer in 1997, at the annual visual effects convention Siggraph, where he saw a short film by Paul Debevec, George Borshukov, and Yizhou Yu called The Campanile Movie. The film - a flyover of the UC Berkeley campus - was generated entirely from still photographs. Like the 19th-century cartographers, Debevec and his team derived the precise shapes and contours of the landscape by triangulating the visual information in still photographs. Then they generated 3-D models based on this geometry, but instead of applying computer-generated textures to the models, they wrapped them with photographs of the buildings themselves. The trick worked spectacularly well. Instead of resembling something out of Toy Story, the buildings and the surrounding hills in The Campanile Movie looked absolutely real.

Cool stuff.

But just a little bit frightening. Turns out this technique makes it incredibly easy to render and mimic human beings in realistic settings:

The ability to create photorealistic virtual human beings raises unsettling questions, especially in conjunction with the means to cut-and-paste them into any landscape. These questions troubled Gaeta himself so much that, a few years ago, he wrote a letter alerting President Clinton to the fact that such technology could be used for purposes of mass deception. (The letter was never answered.)

As it happens, one group deeply interested in the new breed of hyperrealistic CG is the military. Darpa is fast-tracking image-based rendering and lighting for use in immersive battle simulations. In 1999, the US Army launched the Institute for Creative Technologies at USC, where Paul Debevec - Borshukov's former mentor at Berkeley - is now the head of graphics R&D.

We're going to have to have an ever-higher standard of proof for what we see on screens in the future ahead.

Anyway, I also just liked this line about attempts to green-light the first film:

Action-movie mogul Joel Silver was enthusiastic about the script, but with its gnostic allegories, Baudrillardian subtexts, and Philip K. Dick mindfuckery, it was no Die Hard With a Modem.

The whole article's long, but worth the read.

Update: The article's author e-mailed me to say:

Derek:

I'm glad you liked my article on the Matrix! Thanks for linking to it.

Steve Silberman
contributing editor
Wired magazine

Ah, the internet is a beautiful thing. My pleasure, Steve.