When it came to powering DC's Green Lantern, Sony Pictures Imageworks was charged with the superhero light suits as well as the construct energy force that brings objects from imagination to lethal life; the home planet of Oa; and the CG creatures, ranging from trainers Tomar-Re (voiced by Geoffrey Rush) and Kilowog (voiced by Michael Clarke Duncan) and the villainous Krona/Parallax (voiced by Clancy Brown). The opportunity to work on 1,000 out of 1,500 total shots allowed Imageworks to put the proprietary Arnold  renderer to full use for the first time on a vfx-intensive film and to evolve its animation tools and rigging pipeline.
But it began with the suit. Green Lantern, directed by Martin Campbell (Casino Royale ), tells the origin story of reckless pilot Hal Jordan (Ryan Reynolds), who is recruited by the Green Lantern Corp. to save the universe using the power of Will, which is generated by a unique green energy source.
"The suit goes underneath the microscope like a lot of these things when you have a tentpole," admits Jim Berney, visual effects supervisor at Imageworks. "You've not only got Warner Bros., Campbell and Imageworks looking at it, but you've also got DC and the fanboys looking at it too. Spider-Man dons a really cool suit, but it is something he can put on and take off. For Green Lantern, it's like a construct. He puts this ring on and it's the energy that forms around his body and whatever clothes he's wearing. The morphology changes into a suit. To do that, we went with a full-body replacement for those three principal actors. You'll see muscle structure and muscle fibers underneath. There's an outer layer that slides around on top of the muscle layer, and where the symbol is works as a pilot light. And he has these stages of energy: When he's in ready mode, you can see the energy roiling within. It's in the logo and spreads along his pecks. As he gets into battle mode, it starts to fire up and move closer to the surface. As he's charged up and starts to levitate or fly, it surfaces more as he creates constructs. You'll see the energy flare up and move from the core of his chest and also down his neck and shoulder to the ring and blast out to create these constructs."
The energy itself was quite an R&D project. They wanted it to look unique: not like electricity or fire. They wanted the energy to have purpose to its movement. It was another iconic piece of the puzzle. So they tried different iterations of how the energy emitted around his body. It started with concept designs by Grant Majors and others two years ago and then evolved into bringing movement into CG. Campbell tended toward the subtle at first. He didn't want it to look "corny" or "goofy." But, of course, the energy amps up as the fighting and destruction escalate.
Beyond the design of the energy, there was the technical consideration of how to track the suit on a practical head. "We did something similar to the FACS system for the neck because there's no place to hide the blend line," Berney continues. "The digital suit had to deform and the muscles had to move exactly like Ryan's. To accomplish that, we put dots on the neck and those were tracked and then we did a series of deformations and riggings based on a Mova  session for the neck. With that and a bit of hand work, we were able to mimic the neck movements of Ryan and apply that to our digital suit."
Meanwhile, the suit's two-layered system allows the light to transmit through it, so the energy itself can perform as a light source. This, along with everything else, was accomplished through the Arnold renderer, which has been developed as a ray tracer. You can move light and see the results in seconds. It provides artists more creative freedom to make it look cool rather than managing data, calculating shadow maps or doing pre-passes to figure out various other things.
As for Oa, there's a wakeup room comprised of opalescent stone (like an organic honeycomb); lots of canyons and towers; a small mountain of buildings with a tunnel running through the inside leading to the core planet. The mountains in the distance were matte paintings, but everything else was modeled and textured and lit, even the sky made of strange clouds comprised of prismatic light. This also benefited from Arnold as well as Houdini .
Of the various creatures (overseen by David Schaub , animation supervisor at Imageworks), Parallax was the most ambitious. He's made of millions of souls from destroyed planets. He's not a cloud particle or an avalanche: he's amorphous and moves like a predator. It took nearly a year to put together (Neville Page was the creature designer), particularly all the connective tissue but also the cobweb-like, diaphanous cloth that covers the building block elements, so to speak. Within it, a big monster head emerges, which transforms into a more hideous-looking face. "So there was a tricky rigging challenge of going from one head to another, and it was a matter of keeping the topologies the same even though they look different," Berney suggests.
For Imageworks, Green Lantern brought character and environmental work beyond what's previously been achieved at the studio. "Our effects team grew to 45-50 just doing simulations and effects," Berney adds. "We've already discussed how Arnold has progressed. And we've been evolving our animation tools and rigging pipeline: our deformations and coming up with what we call a 'unity mesh.' That allowed us to fairly easily go from one type of character to another without a full rebuild. It's a long time accumulation of technologies coming to the head at just the right time."
Bill Desowitz is senior editor of AWN & VFXWorld.