Faking the Moon – Gerty and beyond

Duncan Jones’ Moon is the story of Sam Bell, the lone occupant of a lunar mining base who discovers not all is what it seems away from Earth. Cinesite contributed more than 270 visual effects shots to the film, incorporating miniatures into a lunar landscape, creating a CG service robot called Gerty and producing several split-screen composites for shots of Sam interacting with a clone of himself. Cinesite Visual Effects Supervisor Simon Stanley-C

09Jul/moon/e_4_moon_vfxfxg: The effects in the film are minimal and never seem to take over. Was that approach part of your original conversations with Duncan Jones?

Simon: It was always to keep the effects quite matter of fact – to create a natural environment. With something like the clone effects, obviously you don’t want to draw attention to the shots, you know, ‘Here is a clone effect’. It’s got to be very matter of fact. They pass drinks to each other, they chat with each other. The lunar landscape shots just had to be as realistic as possible. We always referenced Michael Light’s ‘Full Moon’ book, which is basically everybody’s 1960s reference of what the moon looks like. It’s black and white, very stark. It has a very hard-lit look to it. That’s something we always referenced back to – that very classic look. As far as we know the moon could be green, orange or blue. No one’s ever been up there with decent colour photography. So you’re sort of stuck with this very monochromatic look for the lunar landscapes.


fxg: What was your initial brief from the director for your shots?

Simon: Well, we picked this script up back in November 2007. At our first meeting with Duncan Jones he had a rough shot list. The clone shots were relatively straightforward in terms of the description of them, in that we had to reproduce Sam. So the brief on that was we would be doing multiple Sams. We knew we’d be using some motion control and getting as many close action gags as possible.

The brief on the lunar landscapes was slightly less detailed. We knew there would be some matte painting work for that. There were originally far less shots planned than made it in the film. There was a brief initially to do a CG astronaut that we’d be placing in a handful of shots to do some moonwalking. At the end of the day, we didn’t do a CG guy. We ended up shooting greenscreen astronauts and manipulating them as 2D elements back into shots. The Gerty brief included a handful of CG shots. At that stage, the prop Gerty hadn’t been built. And similarly, we knew there’d be a few shots of the arms for Gerty that they’d want to move around, but it was a little bit sketchy to begin with.

fxg: What techniques did you use to achieve the lunar landscape shots?

Simon: We produced a massive matte painting. That was derived from a shot that was always in the film early on. It was a view from the monitoring room, which is a 180 degree window looking out over the landscape. So we always had in mind that we’d be producing a massive matte painting to cater for that landscape. Through NASA reference and stills from the miniature, we produced the matte painting which we then mapped onto a cyc. Firstly, this was to achieve the move for the monitoring room and then we used sections of it for other matte paintings. This gave us continuity – if you look left, it’s the correct left, if you look straight ahead, the mountains will actually sync up.

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fxg: How did you incorporate the miniatures into those shots?

Simon: There were 60 or 70 shots of the miniature lunar landscape that we incorporated. The miniature was about the size of a tennis court. That wasn’t really big enough for the rover to be able to travel across – to express the idea that it was on one side of the moon and goes over to the dark side of the moon, and that the terrain should change. So there’s always part of the miniature in there, but we’d finish it off with a matte painting to extend it into the distance or cheat the scale of it. We’d take things like the tower and reduce it off into the distance. The moon base, though, was always a practical element that we incorporated. We used Nuke to comp the lunar landscape shots.

fxg: What were some of the details you added into the lunar landscape environments?

Simon: We added little things for the rover shots. We had two different scales of the rover. To sell the idea that it could travel further, we used the smaller one. Those were always pulled on wires. We added all sorts of things like rear brake lights, which we created by taking cues from an Audi. We also enhanced the headlights and put flares into the windscreen. We added dust coming off the wheels, too. For the close-up shots of the rover, we added some little 2D gags, like rocking the cab when Sam gets in and out of it. We added dust falling off it because someone was inside moving it around.

For the extreme close-ups we painted in additional textures like small panels with more nuts and bolts. We tracked this grainy detail back into the rover and the larger harvester vehicle just to try and enhance the scale a little. It was a great model, but next to Sam sometimes the scale wasn’t right. The nuts and bolts, for example, were too big next to him. We’d paste our new panels over as a digital asset onto the rover and harvester.

We also added lens flares – lens flares everywhere! We shot some elements, and we had some in-house elements already like anamorphic lens flares and cheats. There were a few CG lens flares, but I would prefer to use real ones where I could. Duncan loved the flares – when there was a happy accident as things would catch the light and it would flare up. So we put flares and sheens in the windscreens and off camera. There’s always a notion that the sun is out there somewhere bleaching the frame and hazing it up and milking it out a little.

Then there was the dust added back into the harvester shots. There was dust in the plates, but essentially it didn’t move correctly. Duncan was very keen that, because of the point six gravity, the dust should have this parabolic quality. It should rise up and then down. It doesn’t behave as it would on earth. So we created this CG dust and tracked it back on with multiple passes to give it the correct physics for the scale of the harvester while taking into consideration the gravity of the moon.

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fxg: Were the sequences prevised at all?

Simon: Previs came really, really late on the rover shots. As Gavin Rothery (the overall Visual Effects Supervisor) was doing concepts on that, the editor was cutting them in and that defined how many miniature shots would go in the final conform. There was a lot of storyboarding that was done as we were going along, just keeping a couple of days ahead of the shoot. We didn’t really need to previs the clone shots, but I did post-comp them. I comped them as quickly as I could with Shake on set. I was able to take the passes from editorial or straight from the video assist and do slap-comps, really as a proof of concept. Similarly, with Gerty, we didn’t have plates or layouts so there wasn’t any particular previs for that.

09Jul/moon/e_7_moon_vfxfxg: Gerty is a really convincing character in the film. How did you achieve it?

Simon: Gerty’s body was built as a prop. Pretty early on we got access to that, photographed it to hell and measured it to create a digital asset. For Gerty’s arms, we took the physical ones they’d built much further. The practical arms really weren’t posable. They were on a stand and the idea was that they would puppeteer them with fishing wire off-camera. And that worked about once. They didn’t move well and they were too heavy, so we did them digitally. This was always intended anyway as they were going to be travelling around in the background. The idea was that you would be aware of them but it wasn’t a major player. But that developed a bit as the shots progressed. Duncan could see the value of increasingly having more digital arms to add character.

The way Gerty moved around the set was really defined by the set. There was a runner along the top like a monorail hanging down. That defined where Gerty could go, which was good because there were places it couldn’t go. It wouldn’t suddenly appear around a corner, for example. The speed at which it moved and the way it negotiated doors was interesting. We came up with this mechanism that drops down. It’s subtle stuff, it’s in the shots. Some people will notice it and others won’t. It definitely had to drop down when it went through the bulkheads. It would have to wait for doors to open and close. We had to give it weight and make it a little clunky. It’s an old robot, a service robot. It’s a bit like a car factory, very practical and a bit beaten up. It doesn’t move too smoothly. There are little bumps and things as it runs along those rails.


fxg: What tools did you use to make Gerty?

Simon: Again, we were really lucky being able to do an extensive photo shoot up front. We also managed to get access to a lit set of the moon base every weekend. We cued up lighting scenarios for the moon base – day and night. It’s a subtle difference – nighttime had amber lights while daytime had bluer lights. So moments when Sam is meant to be resting had a subtle shift in tone. We went in and shot full HDRI photography on location around the moon base. We did a full survey of the moon base. We were also lucky to get a full LIDAR scan of the main parts of the moon base. We used all that data to construct a fairly rudimentary model of the base, and used that for casting shadows and reproducing the correct lighting. Then we used HDRI for specific shots. We used RenderMan for Gerty, which was animated in Maya with our in-house lighting pipeline to push through all the HDRI. And then it was all comped in Shake.

fxg: What was involved in the Sam clone shots?

Simon: We did a week of motion-control using this mini Milo rig, nicknamed ‘Sprog’, which was a really good rig. It was on rails and you could hand-operate it, record your move and then playblack for repeated moves. Over that week we did 11 shots, with each one having a minimum of three or four passes, with Sam doing a costume and makeup change between setups. They were pretty well planned out, with just some constraints where we could use the motion rig within the moon base. It was a physical set with a closed ceiling, so there were some limitations. You couldn’t put a crane or a big cyclops in the set, but this mini-rig was perfect.

fxg: How was Sam’s performance directed for those shots?

Simon: Sam was brilliant. He was like a human motion-control rig himself. At the time you kind of take it for granted. But he really got it. He really understood about performing with himself. So we’d do a run, we’d make a select, then give him an audio feed. This wasn’t on everything – sometimes the sound department would give him a playback and either overnight or during his costume change, he had a little video iPod and he could watch his previous performance. He was spot on. He always got his eyelines right. There were some really subtle things, like stepping out of the way knowing when he’s about to walk into himself. For the table tennis game he preempted jumping out of the way of the table that his other self knocks and pushes towards him. It was really helped by a brilliant performance.

There was a little bit of mix overlay on the day while we were shooting it, just playing back tapes to Sam and being mindful of where he was standing. We used some props to mark where he had been or where his shoulder needed to be in relation to his other self. For the scene where he touches himself and fixes his cap, we locked him off, gave him a marker and positioned a C-stand so he knew where he had to place his arm. Then there was a little bit of digital manipulation with some roto and warping to fine-tune everything. We warped the fabric a little to make it bend in the right way when they interacted. We composited it all in Shake.

fxg: Just finally, I really like your earlier comment about the matter of factness of the effects in the film and that the effects never take over.

Simon: Well, it sounds cheesy but it was quite a delight to work on. It was an eight week shoot that we shot at the pace of a TV episode. When you’re dealing with things like motion-control, it’s a bit scary because you want to know that the rig is locked down. But it worked. We made a lot of snap decisions there and then on set. Duncan would think about the shot and say: “Can I afford this?” We’d do a budget on the fly. We knew what the shots would involve and what they could afford. So we might delete three Gerty shots for one scene and then add three more in another. It was a very organic process.

Images courtesy of Liberty Films / Cinesite (Europe) Ltd.