'Giant footprint' fireworks revealed to be computer magic

Few of the 4 billion spectators dazzled by last Friday's opening ceremony would have been aware that the spectacular 'giant footprint' fireworks seen in the live broadcast were composed with computer graphics.

The footprints, representing the 29 Olympic host cities of the modern Games, proceeded in sequence across the city's landmarks, including the Forbidden City and Tiananmen Square.

The fireworks were fired on the night, but viewers at home or watching the 'Bird's Nest's' giant screens were seeing computer graphics; only the last footprint was captured live, the Beijing Times reported.

The report said organisers feared it would be too difficult to capture all 29 footprints live from the air, given technical difficulties and strict aviation controls in Beijing. Therefore, the computer graphics were inserted into the broadcast.

Gao Xiaolong , head of the visual-effects team, said the main problem with filming the fireworks live was how to align the helicopter so that the 'footprints' would be seen in a row. Mr Gao said this would have been difficult to manage and could have put the helicopter at risk.

Lu Zhenggang , chief executive of the computer-graphics company Crystal Digital Technology that worked with the visual-effects team, said it took more than 100 engineers and 13 months to create the 55- second sequence.

'We have processed 50,000 gigabytes of computer graphics with 500 servers, the largest in the Games' history,' Mr Lu said in a video clip posted on his company's weblog.