For this preliminary design work, because it was only on stills, we worked almost exclusively in Photoshop. We took the original photographs and painted successive layers of removing more and more detail, flattening out colors and surfaces, until finally we arrived at the graphic style of the books.

"In addition to the simplification, we also added CG snow piles, aerial snow and overall 'de-greening' of the environment. Most of the environment simplification shots were done with a 2.5D projected matte painting approach. We first matchmoved the shots using mostly PFTrack, but also some boujou and 3D Equalizer, and modeled stand-in geo for the shots in Maya, representing buildings, cars and roads. If the shot was locked off or otherwise essentially shot from a single perspective, we would paint a single layered painting that covered all the areas where simplification was required. If it was a moving camera, we would either create a larger oversized painting that encompassed the entire camera move (useful for mainly nodal pans), or select keyframes throughout the shot for a multiple painting approach. In Nuke, the various layers in the painting were projected onto the stand-in geo from the matchmove, and then everything was blended together in the final comp.

"For the falling snow, we developed a highly controllable and directable 3D snow particle system in Houdini that could be tuned not only for amount, speed, and wind acting on the snow, but also for the character and the style of it."

For the final confrontation with Ramona's arch evil-ex Gideon (Jason Schwartzman) at the Chaos Theatre, Scott pulls a flaming sword from his chest and fights a horde of charging hipsters.

The actor wielded a plexiglass sword filled with red LEDs so that he had interactive light cast on him representing the flames; it also gave great reference for the level of motion blur the CG flaming sword should have. He had a cut off version of the sword allowing him to swipe "through" his attackers, and a full-length version for shots where his strikes don't connect. Each time Scott strikes one of the hipsters with his sword they burst into a shower of coins. The coin explosions were created in Maya DNB and rendered in RenderMan; the CG flames again were created in Squirt; the plexiglass sword was replaced with a CG metal blade, which, in turn, was engulfed in CG flames. The flames were overseen by Mick Harper with assistance from Federico Fasselini. Jim Steel, Shahin Toosi & Cleve Zhu oversaw the compositing effort.

"Ultimately, the vfx play a key role in creating the fun, energy and insane 'never seen before' surprises that characterize the film," Churchill concludes.

Bill Desowitz is senior editor of AWN & VFXWorld.