By Neil Smith
BBC News entertainment reporter in Bangkok
Director Oliver Stone has described making a movie about the 11 September attacks as "a very humbling experience".
Stone won Oscars for movies including Born on the Fourth of July
But the Oscar-winning filmmaker denied the drama - to be entitled World Trade Center - would have a political agenda.
Speaking at the Bangkok International Film Festival, Stone called the feature a "24-hour document" in the lives of two New York Port Authority officers who became trapped under the rubble of the Twin Towers.
"They were trapped at the heart of the destruction, near an elevator shaft,"
he said. "They survived 24 hours under extraordinary circumstances.
"It's an investigation into how they survived - how they mentally made it under those terrible conditions."
The 2001 World Trade Center attacks left 2,749 people dead
The officers, Sergeant John McLoughlin and his younger colleague Will Jimeno, are played by Nicolas Cage and Crash star Michael Pena respectively.
They were part of a group of five officers who entered the South Tower shortly before it collapsed. The other three were killed.
Filming took place in New York and New Jersey, though the Ground Zero site itself was recreated in Los Angeles.
"We didn't want to offend people in Lower Manhattan," said the 59-year-old director.
Despite this, Stone says the shoot replicated the men's ordeal as closely as possible.
"I've had a cough in my chest for six weeks now, because the last four weeks has all been smoke," he explained.
"It was all dark holes, smoke and destruction, with only millimetres to work in. It was awful."
The film, he added, was "a very austere, technical attempt to be realistic about what happened - to show it as it really was".
Released in the UK on 29 September, World Trade Center also looks at the officers' wives - played by Maria Bello and Maggie Gyllenhaal - as they anxiously await news of their husbands.
"It was wonderful to go back to working-class people - cops, firemen and their families - and see what their lives were like."
However, when asked whether the world in general and America in particular was ready for a drama about the 9/11 attacks, the director was dismissive.
"I would hate that to be the main question about the movie, though I sense that is what's going to happen," he told the BBC News website.
"I'm not in the business of knowing whether America is ready. You just hope it will be."
As the director of JFK, Nixon and Born on the Fourth of July, Stone has been feted and castigated in equal measure.
Platoon, based on his experiences as a young soldier in Vietnam, won four Oscars in 1987, while JFK won two more five years later.
World Trade Center features actor Jake Gyllenhaal's sister Maggie
However, his 1994 film Natural Born Killers - a satire about two itinerant serial killers based on a script by Quentin Tarantino - was widely criticised for its violence.
And his last movie Alexander, an epic study of the ancient Macedonian leader starring Colin Farrell, received some stinging reviews and flopped at the US box office.
Despite such career setbacks, the former New York University Film School graduate has pledged to carry on regardless.
"I'm not the only director who has had to deal with rejection, failure and defeat," he said.
"But either you get a gun, load it and shoot yourself in the head, or you carry on doing what you love."
Indeed, the three-time Academy Award recipient only admits to one regret after more than three decades in the industry.
Stone's Alexander, which starred Colin Farrell, failed to impress critics
"My biggest mistake was not to direct Evita," he said. "I had two windows of opportunities to make it, first with Meryl Streep and then with Michelle Pfeiffer.
"We came so close to making it, so it was a real heartbreaker for me."
The Andrew Lloyd Webber musical was eventually filmed in 1996 by British director Alan Parker, with Madonna in the title role. Stone, though, believes the singer was not quite up to the part.
"The thing with Eva Peron was she was both a hooker and a saint," he explained.
"Madonna could do the hooker, but she couldn't do the saint."