New Year’s Eve 2020 was always going to be different from previous years. London’s Westminster Bridge and Edinburgh’s Princes Street Gardens both remained empty of revellers and there were no huge explosions of fireworks when Big Ben struck midnight. Instead, both capitals turned to emerging performance art to mark the new year while reflecting the public mood: drone shows.
Over London, an array of 300 light-up drones illuminated the sky, each acting as a pixel to form images representing the year that had just passed: an NHS logo, a heart, the late Sir Captain Tom Moore, a ‘Black Lives Matter’ fist, a blue-and-yellow EU dove and - perhaps most relatable - Zoom’s ‘You’re On Mute’ microphone symbol. In Scotland, the dulcet tones of David Tennant accompanied drones forming up to create a stag, a whale, and a Scottish saltire.
These events were not unique. Though the technology behind them is still new, drone shows are increasingly a fixture at sufficiently large or important public events. An enormous silhouette of a running man in the sky above Shanghai became a viral sensation in 2019, and in November last year, the finale of President Biden’s victory speech in Delaware saw drones take to the sky to form up the United States flag and the number ‘46’, the number of Biden’s presidency. But how exactly do drone shows work?
“Everything we do is proprietary. We have proprietary software, and we have our own drone,” explains Emily Wallace from SkyMagic, the company behind the London show. Each drone in the fleet is capable of travelling up to 15 metres per second and more importantly, is capable of displaying any colour, to the power of 900 lumens, making it visible up to 2km away.
As for movement, both SkyMagic and Celestial Labs, the company that created the Scottish show, use systems that pre-program each drone in the fleet with a set of instructions when they take off. This means that if the signal linking the drones to ground control is lost, it will not impact the performance. So though the drones appear to be moving as a flock to form up whatever images are required, they are actually all moving and performing entirely independently.
“We don’t use waypoints; we use frames like in the movies,” explains Alexey Dobrovolskiy, the CTO of SPH Engineering, which makes Drone Show Software, the software package used by the Scottish show. For each second in a show, the drones know the set of coordinates where they need to be or movements they need to perform, and they remain synchronised using the ultra-accurate time signals from GPS satellites.
Unsurprisingly, safety is also taken seriously during drone shows. On SkyMagic’s drones, the batteries in each only last around 20 minutes, which is about in line with consumer drones, but SkyMagic says that it never lets the battery in each fall below 30 per cent for safety reasons. Dobrovolskiy says that his software contains a ‘red button’ that can be pushed to turn off or land the entire fleet in an emergency.
Designing drones shows is, fairly obviously, a new discipline that requires new tools. So how does an artist put metaphorical pen to paper, when the canvas is several hundred spots of light that can be arbitrarily arranged in the sky? For both SkyMagic’s software and Dobrovolskiy’s Drone Show Software, the process begins in Blender. This is an open-source modelling package that is used across the visual effects industry to make 3D models for everything from video games to Hollywood movies.
The artist can use Blender to do the creative work of designing the animation, dragging, and dropping the on-screen drones to where in the sky they need to be, in 3D space. And they can playback the animation at will, tweaking it to make sure everything is where it needs to be.
When it is time to export, Dobrovolskiy’s software takes care of checking the proposed animations are actually possible within the physical constraints of real-world drones.
“Our plug-in will check maximum speed, minimum distance between drones in 3D and all other vehicle parameters because when you design in software you don’t have physical restrictions,” he explains. “Drones, unfortunately, have a maximum vertical speed, maximum acceleration, maximum braking speed and so on.”
His software also takes care of slicing up the animation file into different sets of instructions to load separately onto each individual drone. It is, though, still a reasonably technical process.
“I don’t think there’s anything in the world right now which is completely plug-and-play,” says Celestial Labs co-founder Tony Martin. As a result, his company has built its own software and plug-ins to aid the design process. For example, his company is able to “pre-visualise” drone shows.
“We’ve got a 3D environment that we’ve created ourselves, which allows us to wander through the drone swarm if we choose to do so,” he explains. “It’s very easy to interface that with a VR headset and actually be able to look around at what’s going on in the display.”
“We can also render cityscapes and other 3D environments into which we can put the pre-visualisation so that we can contextualise the animation with structures and crowds so our clients can see what it’s going to look like before we commit to flying.”
Though the drone show industry is still in its infancy, the technology behind the shows is evolving quickly.
When SkyMagic was founded in 2015, its first shows only used between 80 and 100 drones, compared to the 300 used in London on New Year’s Eve. Similarly, shows typically had to space drones four metres apart, to account for the lack of accuracy in the GPS signal.
Today though, the number of drones that companies can put into the air is ever-increasing, and perhaps more importantly, the industry appears to have settled on using Real-Time Kinematics technology. This enables drones in the sky to be packed together much more tightly, by using additional fixed base stations to augment the GPS signal and help the drones keep their position. As a result, the London show spaced drones just two metres apart.
“I really feel this will open up the door to most urban locations. We can get more drones in a smaller space, and they’re far more accurate,” says Wallace.
The future could see shows become even more sophisticated, with drones capable of forming even denser images.
“It’s going to be higher resolution, more effects, more dots in the sky, greater levels of accuracy. The shows themselves will become ever more complex,” says Martin. “The outputs from the drones will become more diverse in terms of what is mounted on the drones and what the crowd sees.”
Martin also teases that Celestial Labs is working on new types of performance too. “It’s pretty top secret,” he says. “I can say that it is to do with interactivity. [Both] the interactivity of a performer and the interactivity of audiences.”
Drone shows in the not too distant future could be even more spectacular. “We’re playing around on a Game Boy. We’re playing with eight-bit graphics and where it’s going to go is PlayStation 5,” Martin predicts.