Dr. Manhattan had to look photoreal, maximizing the performance and preserving as much as possible in CG. 

They utilized an automated capture technique for the face using multiple cameras to triangulate the scene and convert the data to 3D and would activate a bevy of face shapes that would drive the scene. All of the animation was done in split-screen compared to Crudup's performance. The neck was crucial and driven by a lot of controls to match the actor's movements. But despite the Tron-like suit, Travers says the actor was very committed and cooperative. Then, aside from the neck, the next biggest challenge was animating a ripped, naked body and figuring out how that kind of body behaved. It all had to be re-targeted to Crudup's performance. Fortunately, most of the shots were in closeup with little movement, so they were mainly concerned with matching the position of the CG head with the actor's so that the eye lines worked perfectly.

Also, Dr. Manhattan's entire internal structure was a volume render in keeping with the graphic novel's depiction of the character's interior being made of the cosmos. "We built these internal structures... that would light up the areas inside him," Travers continues. "They would charge up when he experienced a build-up of energy that would shoot through his arm. The internal structure was rendered using the volumetric renderer Svea and the outer skin was rendered in RenderMan." On some occasions, such as the TV studio scene, they had to make his skin look opaque. But they used subsurface scattering through the back of the ears or any of the cartilage areas on his face. Imageworks used Maya for the character animation and texture painted in BodyPaint 3D. Houdini was used for procedural animation.

Imageworks utilized a peak crew of 100. But unlike Beowulf or Monster House or The Polar Express, the advantage here was that they only had to focus on one character, which was not very expressive. However, there was an additional challenge in that Dr. Manhattan had to look photoreal and share plates with real people. Thus, he was treated like a real human being, which had to be worked out during the look development phase. Even the skin textures were borrowed from the actor.

And even Travers admits that Dr. Manhattan's naked body could not be avoided. "He had to be naked because that's what Snyder wanted. He's lost all sense of vanity and is completely apathetic to the human race. We were all giggling as we worked on his private parts, but then, after a while, we got used to it. Certainly, in American society, nudity is so much more taboo than violence, but here's a movie where exploding and tearing and hatcheting people is [talked about less] than whether or not you can see Doc's [blue] penis."

Sony created the Mars Glass Palace, which was built in 3D, procedurally animated in Houdini and rendered in Arnold, which is optimized for ray tracing. 

As for the virtual Mars, Imageworks utilized a lot of the Martian photography from JPL and started with building the Martian sky from very polarized-looking photos and then constructed the landscape from 2D matte paintings all the way to 3D geometry in compliance with the camera targets. The trickiest part was tearing the environment apart when the Glass Palace comes out of the ground or when it's shattered. This involved some pretty intense simulation.

In terms of the Glass Palace, which serves as Dr. Manhattan's perfectly constructed quantum clock, it was easy having two gears intertwining with each other and figuring out the mathematics involved. However, when the pieces come close together, they flip, and that became complicated every time a new ring had to be added. It was built in 3D and procedurally animated in Houdini and rendered in Arnold, which is optimized for ray tracing. Shattering all that glass was a new experience for Sony. It proved a tricky rendering environment because the Glass Palace had to be connected to everything. And light is refracted through the glass along with the dust and debris.

The destruction of New York, meanwhile, went beyond any simulation Imageworks had achieved for the Spider-Man franchise. In tearing everything apart, they literally had to build the internal structures as part of the simulation.

Finally, for the money shot of Dr. Manhattan walking over the hill in Vietnam, which was shot on a bluescreen with a buck of rice patties and actors playing Vietcong soldiers running toward the camera, Crudup was placed on a platform way in the back so they could get the direction right. Imageworks ended up having the Vietcong look like they were blown up from the inside. "We literally built 3D versions of those actors from the inside out: organs, blood, bone, skin, cloth, all individually," Travers explains. "They start out as the actors in the plate and as they're exploding, you're transitioning to their 3D versions of themselves. In fact, it was so gory, that a pared down version had to be made for the trailer."