Read more: 鈥�Dreams on demand: Virtual reality finally delivers鈥�
Dancers have to put up with a lot on stage 鈥� but until now they haven鈥檛 had to worry about an army of 2000 men with rhino heads. The preview of a contemporary dance show this week in Paris, France, showed that the fantastical can be put on stage when virtual reality technology replaces traditional sets.
In the finale of the show, , pre-recorded motion capture let the dancers march alongside rows of surreal animated rhino-men. This was one of several scenes brought to life in 3D 鈥� but the audience wasn鈥檛 wearing special glasses. Instead, the visuals exploit perceptual tricks such as illusory perspectives to immerse the performers in different dream worlds, such as an asteroid-filled region of space.
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The system, developed by a team led by Beno卯t Marini from the French 3D design company Dassault Syst猫mes, is based on software used in industry to model cars and planes. Working in the theatre gave Marini a new set of challenges, though: Dassault鈥檚 virtual environments are typically explored by a few people in a specialised room, but Mr & Mme Reve would have a large audience in a conventional theatre, without screens wrapped around them and without tracking glasses.
鈥淲e had to figure out how to distort the projection to create a perspective that works for every spectator,鈥� says Marini. The team solved the problem by using virtual cameras to simulate different vantage points and find the trompe l鈥檕eil effects that worked best for all positions.
Travelling light
What鈥檚 more, the set-up had to be easily transported and adapted for different theatres. And whereas VR rooms normally beam images from behind their screens, limited backstage space forced the team to design screens for front projection, which produces much more distracting reflection.
鈥淎fter a few trials, we decided to use a slightly grey canvas which makes dark colours more intense,鈥� says Marini. The system they devised uses six projectors controlled by a single computer, with visuals played back automatically in sync with the sound.
The team had hoped that the projectors could replace conventional theatre lights, but additional lighting proved necessary.
The biggest technical challenge, however, happened behind the scenes, as the team explored how to allow for live interaction with the virtual visuals. To capture the motion of dancers on a 14-metre-wide set, three Kinect sensors had to be positioned above the stage, using their infrared cameras to measure changes. Signals from the three sensors overlapped in certain areas, requiring additional processing to extract usable information.
鈥淜inect signals are also disrupted by the dancers鈥� hair or elements of their dance mats,鈥� says Marini. 鈥淲e couldn鈥檛 use the raw signals so we had to develop software to clean, filter and correct the results.鈥�
Hitting the marks
The dancers enjoyed playing with the system, but proved less keen to use it live. When dancers perform, the choreography is precisely timed and they use marked reference points to navigate the stage. 鈥淏izarrely, more constraints give greater freedom to dance,鈥� says , one of the dancers. 鈥淲ith the interactive elements, there鈥檚 the fear that the technology might fail.鈥�
This is why the motion-capture sequences were pre-recorded for the show rather than allowing for live interaction on stage. However, Marini says it鈥檚 just a matter of time before the dancers accept the technology: they have been working together for only just over a year. He is already planning to develop more digital tools for the dancers, such as a library of moves that can be used to virtually create new choreography.
In the future, the team hopes to create shows that involve the audience as well, for example by allowing them to interact with the set using smartphones 鈥� maybe even altering the visuals. 鈥淲ith 400 spectators, however, it鈥檚 hard to know how to make each person contribute,鈥� says Marini.
For this show, the goal was to make the technology inconspicuous and to immerse the viewers in the narrative. Unfortunately, the storyline, inspired by the imaginary worlds of playwright Eug猫ne Ionesco, was too abstract to achieve this, although the talent of the dancers didn鈥檛 fail to impress.
Nevertheless the stunning visuals provided a glimpse into VR鈥檚 potential to give theatre designers an alternative to solid sets that could be less time-consuming and costly. In time 鈥� and if the cultures of dance and technology manage to find common ground 鈥� VR could create experiences that seamlessly blend the real with the extraordinary.
