In 1949, Life magazine photographer Gjon Mili made a pilgrimage to the French Riviera to see Pablo Picasso.
Mili had conceived of a way to photograph trails of light, and he wanted to shoot Picasso "drawing" in midair with a light pen — a process that would leave no trace except on film.
Picasso loved it.
The result, published in Life and exhibited at the Museum of Modern Art, was Picasso’s celebrated series of ‘‘light drawings’’ of bulls and centaurs and the like — photographs that captured him in the act of creating the ultimate in ephemeral art.
Picasso is long gone. But 68 years later, Google has been calling on dozens of artists, animators and illustrators with a high-tech update of Mili’s concept — a virtual-reality setup that enables people to paint with light that actually stays where you put it, at least for viewers wearing a VR headset.
In place of Mili are Drew Skillman and Patrick Hackett, a pair of video-game developers turned virtual-reality enthusiasts who live in San Francisco.
They were trying to build a 3-D chess application one night a couple of years ago when they discovered an unexpected side effect: As you moved the chess pieces around in virtual space, they left trails of light behind. Sensing that their bug was in fact a feature, the two dropped the chess project immediately and hurled themselves at the light trails, hoping to develop a tool for drawing in three dimensions.
In April 2015, seven months after they had cobbled together a rudimentary system they called Tilt Brush, Google bought their company for an undisclosed sum. With Google’s support, Tilt Brush has attracted a team of developers and evolved into a sophisticated tool for drawing, painting, even sculpting in space.
It was released in April as a free add-on to the new HTC Vive, an $800 virtual-reality system produced by the Taiwanese manufacturer HTC in partnership with Valve, a U.S. video-game developer. (It’s on sale as a $30 software package from Valve’s online store.)
This is hardly the kind of reception the two inventors were expecting when they started working on it in Skillman’s apartment, a 400-square-foot studio in South Park, the little neighborhood that has been a hub for San Francisco’s digerati since the 1990s.
‘‘Not in our wildest dreams,’’ said Skillman, 36.
The Tilt Brush name stems from its earliest versions, with which you would draw or paint on a two-dimensional surface that could be tilted in any direction in virtual space. Because the HTC Vive includes not only a virtual-reality headset but also a pair of hand-held controllers and two tracking sensors that map your movement in space, though, the program was revamped to enable you to paint or draw anywhere within a room-sized area.
One controller serves as a palette, with dozens of colors and effects; the other acts as a brush or pen. To watch someone use it is a bit unnerving because the person seems to be making marks in midair, but those marks cannot be seen.
The illusion of delusion disappears, though, when you put on a Vive headset and a step between the sensors. What you see is a phantom creation in three dimensions, something you can walk around, walk through, poke your head inside, do everything except touch.
Google’s investment in virtual reality pales beside Facebook’s $2 billion purchase of the VR pioneer Oculus. Still, Tilt Brush is part of a growing effort.
During the past year, Google has invited more than 60 people to try Tilt Brush and offer feedback, and the company is beginning to unveil their work and participation.
‘‘You would never want to create an artistic tool with only engineers,’’ Skillman said. ‘‘That’s just absurd.’’
According to Tory Voight, Google’s Tilt Brush program manager, those who have joined this artists-in-residence program include Dustin Yellin, a Brooklyn artist known for his 3-D collages encased in layers of glass, and Jonathan Yeo, a British painter whose portrait of Kevin Spacey as the fictional U.S. president Francis J. Underwood was exhibited last year at the Smithsonian Institution’s National Portrait Gallery.
Jeff Koons, whose art works have sold at auction for as much as $58 million, had early access, although he was not part of the artists-in-residence program. Alex Hirsch, the young animator behind Disney’s hit TV series ‘‘Gravity Falls,’’ also has checked it out.
In June, Hirsch posted a sample creation on Twitter, along with an enthusiastic status update: "Drawing in virtual reality makes you feel like a world-devouring wizard god!’’
But the first to try it was Glen Keane, who, in his 37 years at Disney, had brought the warmth of hand-drawn animation to characters such as Ariel (in ‘‘The Little Mermaid’’), Aladdin, Tarzan and Pocahontas.
‘‘When I left Disney in 2012,’’ Keane said recently in his studio in West Hollywood, California, ‘‘I told them it was because I know there’s something new coming — I don’t know what it is, but I need to leave to find it.’’
Enter Tilt Brush, which Keane encountered when Skillman introduced himself at a visual-effects conference in San Francisco. Though still in a primitive state, it was maturing rapidly, and Keane soon became a convert.
In September 2015, seven months before its release, he previewed its capabilities with ‘‘Step Into the Page,’’ a five-minute video.
‘‘The edges of the paper are no longer there,’’ he exclaimed in a voice-over as he did a loose, freehand sketch of Ariel in virtual space. ‘‘This is not a flat drawing. This is sculptural drawing.’’
Scott McCloud, the graphic artist whose book ‘‘Understanding Comics’’ is considered the ultimate guide to the art form, got to play with Tilt Brush when Google invited him to its Silicon Valley headquarters in August.
‘‘I don’t mind saying, I’m a little bit obsessed with this program,’’ he said. ‘‘One thing that appeals to me the most is, it’s still very early. Everyone is asking fundamental questions. We’re still trying to figure out what people are going to use it for. I love it when technology is in that stage.’’
So, what are people going to use it for? McCloud threw out a few suggestions: performance art, virtual sculpture, industrial prototyping.
Keane has a different item on his wish list. Currently, works created in Tilt Brush are motionless; they're essentially static, and Keane is an animator.
‘‘To me, the thing to conquer is to be able to animate in real time in space,’’ he said.
‘‘Just like you have a spatial dimension, you’ve got to have time as a dimension,’’ Keane said. ‘ ‘There’s no reason you can’t do that. I’m not smart enough to figure it out. But Drew is.’’