Issue link: https://digital.copcomm.com/i/426320
12 cgw n o v e m b e r . d e c e m b e r 2 0 1 4 ling, we didn't need to add any science-fiction fantasy overlay to make them exciting," Franklin says. "The science gave us a pure, stark beauty. The images were strong enough to use in the movie." B R I N G I N G O U T E R S P A C E I N Chris Nolan is known for want- ing to film reality in-camera. But, if part of the film takes place in outer space, the only way to do that would be to bring outer space imagery onto the set. "In a majority of visual effects films, actors work on sets with greenscreens," Franklin says. "Over the past couple of films with Chris [Nolan], we've moved away from that. For In- ception, we relied on rotoscop- ing. We felt having real people in real locations gave better results photographically because we didn't compromise the lighting with a giant greenscreen. Chris wanted to take that idea further by projecting images on giant screens with the actors and the sets in front." The projections would give the cast and on-set crew a sense of where the spaceship was in the vast universe. "So, I did a lot of research into digital projectors," Franklin says. "I needed to know the amount of light output we could get. I discovered that as long as we didn't try to project into too large an area at one time, if we used two projectors carefully aligned to double up on each other, and if we shot on 500 ASA stock, with the cooperation of the brilliant cinematographer, we could shoot the interiors of the spacecra with low-level lighting and get a decent exposure ratio with what was outside." Franklin believed, though, that the researchers, TDs, and artists at DNeg wouldn't have gone far enough toward creating the graphics by the time they start- ed shooting, so he would need to replace the projected images with final graphics later. Still, he thought, the rough images would help inform the photog- raphy on-set anyway. The reality was different. "I found that the guys were making such fantastic prog- ress in developing the renders, we could provide advanced graphics early," he says. "I didn't plan this when we went into the movie, but at the end, I realized we didn't use a single green- screen for all the space shots." The production crew built the main sets on huge stages with 100-foot ceilings that had been used for The Wizard of Oz in the 1930s. The set for the spaceship Endurance sat on a seesaw gimbal 250 feet long. Projected on 300-by-80-foot screens outside the spaceship were the images created at DNeg using James' implementation of Thorne's equations. "We shot the images all in-camera with IMAX cameras," Franklin says. "Later, we fixed Revealing a Mystery DNeg Chief Scientist Oliver James and Executive Producer and Physicist Kip Thorne worked together to create scientifically accurate visualizations of curved light around a black hole. And through this virtual telescope, they uncovered a mystery. The process of creating the renderer extended over several months. Thorne would send James equa- tions that James turned into rendered images. "We iterated back and forth," Thorne says. "He would see things that looked strange and send a film clip so I could look at it." One film clip showed an unusual effect. "We saw a weird struc- ture near the edge of the black hole," Thorne says. "I was quite sure it had to be an error. But, the error never went away." He describes the 'error,' which became a discovery: "Let's say you have a black hole in front of a star field, like a night sky," he says. "The black hole gravitation- al lens is like a wavy mirror in a fun house. That's been seen and known for years – it goes back to Einstein himself nearly a century ago. But, what we had never seen before was a complex fingerprint-like structure that we discovered on the edge, really quite beautiful, really worthy of a collabo- ration between a physicist and an artist. It changed in surprising ways as the camera moved around the black hole." So, they pushed it further. "There's this property of a black hole, which is spin," James says. "The faster it spins, the more distorted the light field becomes. It would be too confusing to show that in the film, but Kip is interested in extreme ends. The renderer we had built is like a virtual telescope, so I said I'd push it to the extreme and make images for him. When the spins got incredibly high, 99.9 percent of the maxi- mum spin a black hole could have theoretically, the distortions became more and more extreme." "It produces a beautiful pattern," Thorne says. "I think it's exciting in that I believe there are some interesting mathematics to be sorted out. There has been a lot of work by other physicists to study grav- itational lensing by black holes where the source of light is near and the camera is far away on Earth. For science fiction, you want the camera close and the source of light far away, or sometimes close. There has been little work where the camera is close." Thorne continues: "It turned out that there is this little discovery where no one has explored. It's not profound. But, it is a mys- tery. It's highly enjoyable. This is truly a fun mystery that I expect others will sort out. But, not in the next few weeks. What's going on in there is too complex. The mathematics associated with that pattern may turn out to be rather neat." –Barbara Roberton