Raising the roof: the tech behind The O2’s incredible Rugby World Cup light show

Towers of tech

If you’re yet to be convinced, here are just a few of stats behind one of the world’s biggest ever ‘projection mapping’ stunts: 29km of cabling, 68 projectors, 144 lighting fixtures, 1.8km of rigging, ten media servers, 250m of truss and over 14,000 man-hours.

This all combined on Tuesday to transform the crest of The O2 into a rose in bloom, which appeared to rise from the interior of The O2 itself and blossom on its surface (scroll down for the video). It’s just the first of many visual tricks you’ll see over the next six weeks.

Projection mapping technology – a process where images are projected onto an object’s surface to create optical illusions that completely change its appearance – is far from new. You might have seen it before on the front of Battersea Power Station or emblazoned on the side of Sydney Opera House.

But one area where this project is in a league of its own is scale. Not only is The O2 larger than most structures on which projection mapping has been tried, its ‘big top’ shape presents a near-insurmountable range of tech challenges.

Dome truths

You might think The O2, a leviathan of white canvas, would be the perfect surface on which to project an image. Not so, according to Projection Artworks, the company behind ‘Wear the Rose’.

Projectors are designed to render images on flat surfaces. Which means that, without the use of some clever tech, The O2’s curvature would make the Rose look like it’d been under the studs of an All Blacks scrum.

To compensate for the warped surface, a software suite called D3 was used to calculate how each projector should adjust its part of the whole image. All the visuals are fed through D3, where they’re dissected into tiny pieces for each projector.

Which all sounds very easy, in theory. In reality, this required the entire surface of The O2 to be 3D-scanned from above. At one point on the O2’s surface, toward the very peak, there is a spot where the output of 22 projectors cross, and all are working to the same visual beat. It’s a feat akin to getting 22 synchronised swimmers to touch toes and stay in perfect formation.

Right angles

As if this wasn’t difficult enough, the team also had to combat another problem – viewing angle. The blooming rose appears to burst up from the bottom of The O2, an amazing effect, but one which comes at a price. As Projection Artworks explained, the deeper you attempt to create an illusion of depth in a flat object, the more restricted the viewing angle of that illusion becomes.

By allowing the rose illusion to run so deep into the structure of The O2, the team created a highly restricted position from which the full effect can be seen. Which means those of you hoping to get a glimpse of the magic from atop The Shard will be looking through your binoculars in vain.

Tweet The O2

Luckily, there is an impressively techy alternative to flying over The O2 in a helicopter – ‘Wear the Rose’ will also be projecting 5,000 fan tweets per day onto the roof throughout the tournament and sending GIFs of these messages back via Twitter.

To achieve this, cameras have been mounted above the projection, which capture the tweet as it moves across the roof and sends this back as a retweet.

Which means the digital journey of this seemingly simple trick is: your phone, to twitter, onto web servers, into the projection software, onto The O2’s roof, into its cameras, then back to the servers, Twitter, and, eventually, your phone again. And there we were complaining about our temperamental smart light bulb.

To get your face onto The O2, just tweet a message of support to the England team with the #WearTheRose hashtag. Then pray to the Gods of social media, before raising your smartphone in honour of the men who hand-hoisted 60kg projectors and spent 14,000 hours in the September rain to make it all happen.