One thing almost all the films of British filmmaker Peter Greenaway have in common is the way their stories evolve from structural elements. Greenaway is less interested in straightforward narrative and psychodrama than in the way the elements of a system can lead you into an understanding of story and character. In The Cook, the Thief, His Wife & Her Lover it was rooms and costumes and coordinating colors. Drowning by Numbers concerns three women with the same name, each of whom drowns her husband. And in The Belly of an Architect, architecture is as much a character as the one played by Brian Dennehy.

Before he started making his own movies Greenaway worked as an editor on short documentaries for Britain’s Central Office of Information–making what he calls “soft-core propaganda.” It may have been then that he developed the formal obsessions so apparent in his own work. He made a total of 19 shorts before his first feature, The Draughtsman’s Contract, which was released in Europe in 1982. With few exceptions they are on some level parodies of COI films, pseudo documentaries–complete with authoritative-sounding voice-overs–that explore their subjects by obsessively cataloging and listing: defenestrations, battles, the alphabet, and things having to do with birds all serve as frameworks for his creations.

The Falls, finished in 1978 and released in 1980, might be considered Greenaway’s longest short rather than his first feature. The incident it describes, known as the Violent Unknown Event, can also be seen as the turning point in Greenaway’s career; after the Event he abandoned the documentary style and started making films that could more comfortably be called narrative. It stands as a fulcrum between the two styles.

We learn from the film that the Event (or VUE), about which little is understood except that it may have been caused by birds, has claimed 19 million victims, most of whom appear to be turning into birds. The names and characteristics of all of the victims have been compiled in a vast encyclopedia, and the film consists of short biographies of 92 of these people. Using both original and found footage–and footage shot for earlier projects–Greenaway creates a wholly convincing vision of an alternate reality. Vintage clips of people trying to fly with synthetic wings illustrate “Potagium Fallitus,” or the affliction of turning into a bird. Some victims are played by actors, others are identified by found photos–including one of famous bird victim Tippi Hedren. A photo of the Brothers Quay, the real-life experimental filmmakers, introduces the biography of “Ipson and Pulat Fallari,” victims suffering from high blood pressure and synchronized blackouts. Others fear darkened cinemas or drive compulsively in circles.

It’s a documentary but it’s not. And the revision of the form makes us adjust our expectations about how we get to know characters. Whether or not a particular character knows the writings of a famous ornithologist, or if he or she has become allergic to speeds over ten miles per hour, is far more important than his or her age or occupation.

Though most major American cities have hosted Greenaway retrospectives, his early films are showing in Chicago for the first time this weekend at the Film Center of the Art Institute (Columbus Drive at Jackson). The Falls is playing Sunday at 6, and screenings of shorts are at 6 and 7:45 Friday and Saturday. Admission is $5, $3 for members; call 443-3733 for more.