Digital Drama: The technology transforming theatre
"Vidiots, they sometimes call us," admits Timothy Bird.
Some people in the theatre industry don't take kindly to the innovations that Mr Bird and his team at Knifedge are introducing to the stage.
Innovations like a computer-generated avatar sword-fighting an actor live on stage in his most recent show Pippin, transporting the audience to the world of a computer game.
Or the sight of a Seurat painting gradually coming to life on stage in Sunday in the Park with George, the show which cemented Knifedge's reputation with an Olivier award for Best Set Design in 2007.
Impressive feats like these by Mr Bird and others like him have meant that in the last five years the role of "video designer" has become increasingly common in theatrical programme credits - a term hardly known a decade ago.
So who are these "vidiots", and what do they want to do to theatre?
No 3D glasses required
Mr Bird says he moved from working in television production to theatre, because TV follows a standard format that has not changed much over the last couple of decades.
"Theatre is very different," he says.
In a movement that some critics are calling "technodrama" and "mixed reality", shows across the globe have been embracing the latest digital technology.
3D projections, virtual-reality masks for actors, stop-motion camerawork and computer animation have all been put to use.
And as the hardware and software become ever cheaper, the methods are trickling down to fringe theatre too.
They are no longer just the preserve of big-budget shows by the likes of Robert Lepage. The French-Canadian digital pioneer has brought the latest technology to world attention, for example by experimenting with 3D projection at New York's Metropolitan Opera.
But what excites Mr Bird are the advances in 2D video projection technology.
The real digital revolution, says Mr Bird, is that you can now map your 2D projections onto your particular stage set in a venue - rather than merely project onto a flat surface.
"This gives the projected images a 3D quality without the audience having to wear the glasses", says Mr Bird, "which would kill the theatrical experience."
To achieve this, the Knifedge team spend thousands of hours at their desktops in their central London base, using software to map sets.
They use modelling software like Vectorworks and 3D animation software like Maya, in tandem with more traditional techniques like card and glue modelling.
When the time comes to transfer these visions to stage, the team often bring sleeping bags to the theatre, working through the night to bring their designs to life.
This commitment to detail extends beyond the theatrical stage. Mr Bird's troupe of video designers - what he calls an "imagineering outfit" - also illuminate pop concerts, commercial product launches, and in one recent commission, an international swimming gala.
If one person's career encapsulates this transition from traditional, analogue theatre to the brave new world of digital, it is that of William Dudley.
He has seven Olivier awards to his name, in a professional career spanning six decades. But to video designers he is probably best known for his work on The Woman in White in 2004, which featured ground-breaking video projection techniques on to moving pieces of scenery.
His digital conversion happened in 1990 when a poster designer friend suggested he get an Apple Mac. "What the hell is that?" he recalls saying at the time. But then he used it to start using Photoshop version one, which he says marks the turning point in his career.
Stage designers at that time still predominantly used spray paints and paper negative cameras - a primitive kind of photocopier - to devise stage sets, he says.
Mr Dudley used video projection for the first time in 2002 with director Tom Stoppard's Coast of Utopia trilogy at the National Theatre.
He recalls: "Tom said: 'I've written it like a movie, I'm not apologising, it's your problem.' I told him I've cracked the problem, thanks to video projection."
Working on the show, Mr Dudley learned you could put projectors right next to the stage, allowing actors to walk in and out of the projection - "a similar effect to Woody Allen's Purple Rose of Cairo".
"I seek to make theatre as magical as cinema is," says Mr Dudley. "I always wince when people say that what I do is mere spectacle."
Theatre has been exploring the magical possibilities afforded by science and technology since the dawn of drama.
"The Romans were the technology buffs who liked to show off their engineering skills," according to David Wiles, professor of theatre at Royal Holloway. "They were interested in things like collapsing mountains, and using hydraulics to flood the stage."
"The Greeks would fly gods in on a crane, but in general they were more restrained," adds Professor Wiles, who is co-editing the Cambridge Companion to Theatre History. "They were more theoreticians, interested in the science of acoustics in the auditorium."
But would the Romans have introduced live tweets into the Coliseum if only they could? Would the Greeks have been interested in generating a chorus using virtual reality avatars? Is there a line technology should not cross, when the drama itself becomes compromised, in any age?
Many in the theatrical community - from directors to lighting designers to actors and critics - have openly attacked the work of video designers, saying it distracts the audience, breaking the spell of the performance.
"In this age of attention deficit disorder, I can understand technology has a purpose," says Matt Wolf, theatre critic for the International Herald and Tribune, wryly.
"Technology can serve to replace the power of the imagination," he warns.
Mr Wolf says he believes in the old dictum that the power of theatre resides in "two planks and a passion" - when that exists, technology can only interfere.
"It seems odd," he adds, "that theatre is seeking to emulate cinema - let celluloid do what it does best."
Video designers openly joke about this resistance they face. Mr Dudley has battled with what he calls "the campaign for real scenery", while Timothy Bird at Knifedge is always seeking to build alliances with what he calls "the enlightened lighting community".
But some influential voices have spoken up to defend them.
"It would be crazy for theatre not to embrace new technology, especially video projections, the results can be brilliant," says the Guardian's theatre critic, Michael Billington.
Technology can also be overpowering on stage, but that is the fault of the directorial concept, adds Mr Billington, who analysed the evolution of British theatre after World War II in his book State of the Nation.
"For theatre to turn its back on new technology would be as if it had rejected electrically controlled lighting when it came into play in the 1880s," says Billington.
However, even the practitioners of the art admit it has its limitations.
"If the directors just chuck technology at it [the production], it becomes a spurious gimmick," admits Timothy Bird. "The trick is to keep the liveness, the human element."
"Some directors see it as a distraction," says Dick Straker, of the Mesmer collective, who set up a very informal video design team at the National Theatre a decade ago.
"They see the strength of theatre as the one-to-one live relationship between actor and audience, and they say: 'Why would you want to intervene with pre-recorded special effects, by making it mediated, like TV?' - I can sympathise with that."
Dick Straker believes a new generation of video designers is waiting to burst onto the stage, and it will change things in ways we cannot yet imagine.
"Ten years ago people like myself were just dabbling in this technology, now students consciously choose to be video designers for theatre," he says.
"I see a difference in these twenty-somethings, digital technology is completely integrated into their lives, they are a different breed and their relationship to the medium is different."
The incumbent crop of video designers is already experimenting with the kind of tools this new generation will have at its disposal.
The trend appears to be towards ever more interactive sets, with effects triggered by actors live on stage.
Knifedge is testing the use of Xbox Kinect cameras for this purpose (which detect movement for the purpose of video gaming), and chemically treated glass that turns opaque with an electrical charge, creating an instantaneous projection screen.
Dick Straker is interested in infra-red devices to cue action on stage.
William Dudley - who now "haunts car shows" to find the latest technology for theatre - is intrigued by new digital lenses that use algorithms to pre-distort images so they appear flat when projected onto curved surfaces, like tent ceilings. "There is nothing to stop us doing planetarium-type shows," he says.
In fact, he is contemplating using such technology for his version of Sunday in the Park with George, to run at the Chatelet Theatre in Paris in April 2013 - with more than a year to go, his team are already on site, finalising the video design of the show.
The "vidiots" may yet take over our theatres, with even more impressive tricks.