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As the ceremony got under way with a dramatic, drummed countdown, viewers watching at home and on giant screens inside the Bird's Nest National Stadium watched as a series of giant footprints outlined in fireworks processed gloriously above the city from Tiananmen Square.
What they did not realise was that what they were watching was in fact computer graphics, meticulously created over a period of months and inserted into the coverage electronically at exactly the right moment.
The fireworks were there for real, outside the stadium. But those responsible for filming the extravaganza decided in advance it would be impossible to capture all 29 footprints from the air.
As a result, only the last, visible from the camera stands inside the Bird's Nest was captured on film.
The trick was revealed in a local Chinese newspaper, the Beijing Times, at the weekend.
Gao Xiaolong, head of the visual effects team for the ceremony, said it had taken almost a year to create the 55-second sequence. Meticulous efforts were made to ensure the sequence was as unnoticeable as possible: they sought advice from the Beijing meteorological office as to how to recreate the hazy effects of Beijing's smog at night, and inserted a slight camera shake effect to simulate the idea that it was filmed from a helicopter.
"Seeing how it worked out, it was still a bit too bright compared to the actual fireworks," he said. "But most of the audience thought it was filmed live - so that was mission accomplished."
He said the main problem with trying to shoot the real thing was the difficulty of placing the television helicopter at the right angle to see all 28 footsteps in a row.
One advisor to the Beijing Olympic Committee (BOCOG) defended the decision to use make-believe to impress the viewer. "It would have been prohibitive to have tried to film it live," he said. "We could not put the helicopter pilot at risk by making him try to follow the firework route."
A spokeswoman for BOCOG said the final decision had been made by Beijing Olympic Broadcasting, the joint venture between the International Olympic Committee and local organisers that is responsible for providing the main "feeds" of all Olympic events to viewers around the world.
"As far as we are concerned, we let off the fireworks - that's what's important to us," she said.
Mr Gao said he was worried that technologically literate viewers who spotted the join might be critical, but comments online suggested more admiration of the result.
Although the event as a whole received rapturous reviews abroad, that has not been entirely the case at home. Some internet comments were hostile, saying that while it looked stunning the contents were vacuous.
Others focused on the sheer numbers of people involved - more than 16,000 performers, mostly from People's Liberation Army song and dance troops.
"That certainly showed China's unique character," said one comment. "Namely, that we have 1.3 billion people."
