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n n n n VFX•CG Films (Top) Animators at Weta Digital referenced jackhammers for the digital staplers' movement. (Bottom, left to right) Artists matchmoved Noomi Rapace's torso and rebuilt it digitally. All the tools used in the surgery are computer-generated. tion in the effect and have it escalate dramat- ically in every shot." As they had done for the disintegration, the effects team also looked for examples from re- ality to create the DNA part of the sequence. "For the engineer, Ridley [Scott] had a strong idea about what he should look like, but we were able to design the DNA shots," Hill says. "The brief from Ridley was fantastic. He said, 'It's like a war in there.' " To create the engineer's DNA, the artists used, as reference, the spine bones of a fish that they wrapped digitally into a double he- lix and rendered with the material quality of tooth enamel. "That gave us room to infect it with the dark and sinister and corrupting in- fection," Hill says. Burning polystyrene foot- age provided elements that the team fed into shaders to create the evolving infection. "Our effects team did a fantastic job of smashing up the DNA and creating the blood in the veins," Hill says. "We used [Autodesk's] Maya to create an enormous particle simula- tion, and used [Side Effects Software's] Houdini for cell mitosis later." For rendering, the team used Pixar's PRMan, and for compositing, Nuke, all with the studio's proprietary code running on top. 50 June/July 2012 The sequence takes place near a waterfall filmed in Iceland, and when the engineer falls, he splashes into digital water created to allow interaction with the digital character. "The mood of the shot when the spine rips open, his head falls off, and his arm breaks is dark and violent," Hill says. "It continues to be fast paced, but by the time he reaches the bottom of the waterfall, the mood changes. We took the particle sim of all the cells that have broken apart, all the broken bits of DNA, and reform them into a fantastic-looking DNA with a clear double helix structure. We wanted some- thing filmic, not a medical visualization. We used extreme depth of field to make the whole scene look big. We see the DNA re- create with hundreds of cells splitting and growing. We see that the engineer sacrificed himself to create life. Thelvin Cabezes and Christoph Saltzmann, the leads on the sequence, did a stunning job on this shot." Abominable Surgery In stark contrast to the beautiful opening se- quence, the artists at Weta Digital also created what is perhaps the most horrific sequence in the film, one people are as likely to remember as the classic chest-bursting scene in the first Alien. previs, our jaws dropped," Hill says. "We thought, 'They can't want to do this. It's too disgusting. But, they did. We became kind of numb to it after a few dailies." In this sequence, the character Elizabeth Shaw "When we saw the medpod sequence as (played by Noomi Rapace) is pregnant. The fa- ther of her "child" is Charlie Holloway (actor Lo- gan Marshall-Green), but the "child" is an alien because alien DNA has infected Holloway. Shaw crawls into a medpod bay and re- programs a machine designed to perform ab- dominal surgery on men, to do a C-section on her instead. "She's lying there and the creature inside is bashing against her abdomen," Hill says. "We see baby feet and elbows pushing and distorting her abdomen." To create that effect, the artists match- moved Rapace's torso, rebuilt it digitally, pro- jected the plate onto the digital model, and then enhanced that model to correct stretch- ing and fix specular highlights. "She's covered in sweat," Hill says. "We needed to re-apply all the reflections and shadows from all the tools on her distorting and undulating body." Animators referenced car machinery to cre- ate the motion of the tools, all of which are CG. "We added a slightly spidery motion to make the tools feel sinister," Hill says. "And we added one or two tools more than necessary to make the scene feel claustrophobic." The first gory shot happens when a laser slices open her belly. "We needed to match- move Noomi [Rapace], create belly geometry, slit that open, and build her internals," Hill says. "You can see steam rising from where