With Cowboys & Aliens, director Jon Favreau (Iron Man) relied on his strong relationship with Industrial Light & Magic to again deliver vital and complicated visual effects for this otherworldly and Western adventure. We talk to VFX supe Roger Guyett and texture supervisor Martin Murphy about ILM's approach to the film's mysterious aliens.
In addition to the alien characters, other visual effects were required for the speeders, the alien spaceship, its interior, environment re-creations and the head up display for the bracelet. The early alien invasion of the town of Absolution utilized both practical laser lighting and fire effects, along with practical ships and effects enhancements. Interestingly, ILM artists had enhance the initial look of the alien 'bolos', the lasso-like cables that take people into their ships, with extra lights, etc - after viewers thought the studio had failed to paint out the cables in the film's first trailer. For a scene of the two heroes - Jake and Ella - riding atop a speeder, production shot the actors on a practical mock-up against bluescreen, as well as producing digi-doubles for wider shots.
- Watch interviews with Roger Guyett and Martin Murphy, plus clips from the film including shots of one of the aliens, in this video fxguide filmed at ILM for The Daily.
Although ILM was the lead facility on the film - under visual effects supervisors Roger Guyett and Eddie Pasquarello - other houses also made significant contributions. Legacy Effects fabricated a practical alien used as reference on set, as well as a full scale alien speeders. New Deal Studios constructed a miniature paddle steamer seen upturned that ILM comped into the final shots, while Kerner Optical built a miniature of the alien ship and bluescreen stand-ins. Further digital visual effects work was completed by Fuel VFX, The Embassy, Ghost, Shade VFX, with previs from Halon Entertainment.
For visual effects supervisor Roger Guyett, Cowboys & Aliens presented a unique opportunity to create realistic alien effects in a Western movie mash-up. "There's a classic style that the movie was trying to keep to," says Guyett, "such as The Searchers or those classic Ford epic Westerns that I grew up watching. Or movies like Unforgiven that have a hardness and a real flavor to them. We were trying to make sure our aliens fit into that world and had that same characteristic - trying to make them feel that although they were aliens. They existed in that environment and had all the dust and carried all those qualities with them and had all those organic qualities."
Director of photography Matthew Libatique shot Cowboys in anamorphic format on film, furthering the classic movie feel. "The anamorphic format and widescreen were what people associate those Westerns with," notes Guyett. "And anamorphic lenses behave differently, they have a more organic feel to them. They're not perfectly round and there's a different depth of field you get out of it." The anamorphic format gave ILM no extra room to re-frame shots, a challenge with having both nine foot aliens and smaller humans in the same space. "So we would tile," says Guyett. "We would go around and shoot more areas in case we lost a mountain top, because the letter-box format of anamorphic doesn't give us much height."
Guyett was drawn to the single source lighting and high contrast lighting approach taken on the film, although he embraced the colors of the New Mexico area where the desert scenes were shot and enjoyed contrasting that with the alien technology brought to the Old West. "There wasn't a lot of color in that era because people had to use dyes or whatever," he says. "But now you add the color of the white blue from the bracelet, and that to me is visually interesting because you've got this contrast and it's visually more shocking now that you're playing with those elements - suddenly a new technology they come across and have to deal with."
To film scenes that would later include ILM's digital aliens, production relied on a nine-foot Legacy mock-up on set. "It was just fascinating seeing this nine-foot thing and someone standing next to it," says Guyett. "Everyone immediately gets the physical presence of that character." Scenes of the cowboy/alien gun battle, in which the aliens move at twice the speed of the humans, were slightly more challenging to realize.
"So, you've got an alien running around and a bunch of cowboys who are supposed to shoot at it," proposes Guyett. "How do they know where to shoot if they're on horses? They're supposed to ride through the shot and aim at something - you've got to tell them where to aim. We had a bunch of guys who wore gray suits and funny hats that made them three feet higher. And people always want to look at their faces, even if you tell them that the face is three feet higher - there's a natural human reaction that everyone looks at the faces. Jon noticed this happening and he took a marker pen and drew faces on the top of these heads!"
For animation of the aliens, ILM initially explored motion capture but found that the physiology between the creature and human being performer would be too different. Animation supervisor Mark Chu co-ordinated animators at the studio, giving the aliens both subtle movements for close-up scenes and a much more menacing feeling in scenes where they attack. "We also did funny little things," adds Guyett, "where we had flies gathering around the aliens, even more than with the humans. I thought that was a funny thing for the aliens to have to deal with. You don't want to over-drive ideas like that, but when you're spending so much time working on the personality of the creature, you think about all these things."
Detail in the alien creatures came not only from the environment around them, but of course also from ILM's skin and texture work. "Texturing something here usually begins with receiving artwork," explains ILM texture supervisor Martin Murphy. "The art department produces close-ups and breakdowns of certain areas of the skin or fur or cloth. If it's a hard surface object they look at how the light would work in different situations. We then have a turnover meeting where we talk about how long it's going to take, the technical aspects involved and how many people it will take to get the job done."
Once the texture artists received a sculpted and an approved computer model, they would then attach paint, color and displacement maps. Then they begin a back and forth look development process with a technical director, who sends through screenshots and test frames to see how the textures are working on the creature.
"The technical director," says Murphy, "works more on the materials and you as a texture painter are working on the images or maps from diffuse, specular, bump, displacement and scatter. They all plug together into a shader and the TD can fine-tune and tweak and work magic with that. When the two work together, that's when you get a surface quality that is complex and interesting and real."
One of the biggest challenges on this film, from the texture artists' perspective, was that the aliens were to be seen in both a dark cave environment and harsh sunlight. Their wounds and scratches would also be seen close-up. "In fact," notes Murphy, "one of the first things a texture artist will ask is, 'how close is this character to the camera?', because that will change your complete set-up. You're going to break the character's geometry up into what we call partitions. We can assign a certain amount of resolution per partition. So if a character comes very close to the camera, we know that one map - say 4096 x 4096 pixels - will hold up in resolution to perhaps just the center of the face, and then we'll have to map different ones onto different sides of the head."
That kind of high resolution modeling applied also to other parts of the aliens' bodies, such as the hands, since a low resolution hand touching a high resolution face would not look right. Murphy says texture artists generally aim to create texture maps that are slightly higher resolution than a typical frame width of 3000 pixels, but there are times when background characters, for example, become more prominent and so extra paint detail needs to be added to the original work.
"We use the word 'paint' when we talk about texturing an object, but it's a bit of a slang," notes Murphy. "It really is about creating levels of maps - when light hits them they tell the material to react in a certain way. So we paint the diffuse color, and that would be on top. And underneath there would be an area map that lets a certain amount of sub-surface scattering in. And then under there would be a bump map to get fine ridges or details in the surface. Then there's a displacement map which is another black and white map which pushes the surface of the model to get even finer detail. Then under that would be an opacity map, perhaps for a piece of clothing as a tear or a rip on the side. It really is all these maps working together so that they work well when light is projected onto them."
Even the aliens themselves were a combination of different types of materials, especially in the case of the cave alien. "There are some parts of him like his arm that you can see into," says Murphy. "It's almost like glass or ice or gelatiny surface that blends into a dryer area. The there's pieces of him that are more like a soft-shell crab or shiny and wet."
The film's aliens see their fair share of battle on Earth and have the scratches and markings to prove it. Murphy's team was responsible for adding the extra layers of dirt, grime and cuts and scars necessary to add a high level of realism to the aliens. "We tried to add in details so that it's not just one clean alien," says Murphy. "Every alien you see close to camera has its own little features, dirt arrangement, wounds here and there. It really grounds the character to the environment."
In particular, the texture team created a yellow fungus-like look on the scars of the aliens, after Favreau requested that they experience a very unpleasant biological reaction to being wounded on Earth. To paint the fungus, Murphy says he looked to real-world reference as a starting point. "I scanned the internet for pictures of mold and growth on trees and anything I could find that looked like it had some sort of beginning growth or end growth, where the edge was a little bit more developed than where it began. I made this huge fried egg pattern and used sections of that and just applied that to the color with different textures rendered all the way through, so it looked like it belonged there."
Murphy's reliance on real textures as reference has come in handy before. For Rango, he bought and photographed multiple types of leather from second-hand stores to help with painting textures, and he looked to an unlikely source for that film's giant eye in the aqueduct sequence. "The director wanted to see all those filaments that an eye has, like a baleen on a whale. In my apartment, I had these dried sticks that were sitting in a vase. They were thicker at the bottom and at the top they had a little bit of a wobble to them and then they got really thin. So I put down a flat blanket in my living room, and took them out and laid them all flat and shot them from the top, and those were exactly what I needed. So I took a bunch of high resolution shots of those, tiled them altogether, put them on a spherical piece of geometry in Maya, rendered them out super hi-res, took them into another program and painted little aberrations into them and that was my texture. And back into the vase they went at the end of the day."
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