So the Metropolitan Opera didn't produce the universally acclaimed Ring cycle that the Wagner community was hoping for. But a great behind-the-scenes documentary film about its creation, titled Wagner's Dream, is being simulcast at 6:30 p.m. Monday in six Philadelphia-area movie theaters. And whatever one thinks of the $19 million production itself, the film is destined to be one of the classic documentaries about opera.

The Met gave filmmaker Susan Froemke extensive access to workshops, rehearsals and the cast's superstars — without apparent whitewashing. OK, the film doesn't quote New Yorker critic Alex Ross' damning assessment — "the most witless, wasteful production in modern operatic history" — but that, frankly, could have come out too late for the film's production deadlines.

With its huge technological resources, the Met's new Ring could have been a landmark in the four-part, 16-hour saga's 136-year performance history. The appointed producer, the Canadian theater artist Robert Lepage, seemed ideal, partly due to his longtime attraction to all sorts of mythology. His Canadian Opera Company's production of Stravinsky's The Nightingale, staged in a wading pool, is one of the most imaginative and resourceful opera productions of the past decade.

Lepage's Ring set, however, turns out to have been all too accident-prone. Consisting of 24 huge moving planks that are in fact video screens with endless scene-setting possibilities (and were inspired by the tectonic plates of Iceland), the set was designed to gyrate in ways that realize the impossibly magical stage effects that composer/librettist Richard Wagner envisioned but never came close to realizing in his lifetime.

Lepage has always pushed technology to the edge: His Hamlet adaptation, titled Elsinor, was once canceled 10 minutes into the performance due to a computer meltdown. But such mistakes simply can't happen at the far bigger and way-more-expensive Metropolitan Opera. In the film, one sees the set getting stuck from both onstage and offstage perspectives, ruining the climactic effect in the opening night of Das Rheingold. Time and again, Met czar Peter Gelb says the medium of opera must be pushed into new terrains in order to survive. He's right. But some terrains are more congenial than others.

There are no villains in the film. No scapegoats — not even Gelb, one of the most controversial figures in the performing arts. He comes off well: Super-tough but thoroughly reasonable and passionately engaged with the project on every level. One is charmed by leading soprano Deborah Voigt, who sang Brünnhilde for the first time. In the early scenes, she walks into a Ring photo shoot, hears "Ride of the Valkyries" on the sound system and quips, "They're playing my song." When Voigt tripped over her dress and fell in her first entrance in the opening night of Die Walküre, she vowed that the staging would be changed for future performances. "Be careful what you wish for," warned one onlooker. "He [Lepage] might fly you in." Though Philadelphia bass Eric Owens had a major career breakthrough singing Alberich in Das Rheingold, he's seen in rehearsals looking wide-eyed and wary.

So was the Ring Lepage's Waterloo? Hard to say. The set was one big wild card, so it's hard to know to what extent his ideas made it to the stage. There were significant differences between the workshops in Quebec (where Lepage is based) and what was possible on the Met stage. After all, the New York crew was expecting a 50,000-pound set and got a 90,000-pounder.

By part four, Götterdämmerung, many of the concerned parties seem weary and resigned. Lepage can't hide his disappointment when he talks about how he had hoped he could get the machine to figuratively stand on its head at that point. Instead the machine had come to dictate the staging rather than the other way around. Even his stage direction (Lepage himself is a fine actor) may have fallen by the wayside amid fear of the machine.

In the theater, I loved Die Walküre and Siegfried. Götterdämmerung seemed haplessly unfinished. I never saw Rheingold in good working order — or with singers who seemed to be doing more than getting through the opera, composure intact.

At one point, Lepage compares himself to Christopher Columbus convincing his crew that they won't fall off the edge of the Earth, and inspiring faith that a great continent awaits. At this point, the Lepage Ring has only found its Lesser Antilles. Is the Met, in future revivals, willing to devote the time and money to allow Lepage to keep sailing?

Information and tickets for Wagner's Dream: www.metoperafamily.org or www.fathomevents.com

Contact music critic David Patrick Stearns at dstearns@phillynews.com.