"To top it off, they had the smoke from the locomotive flying through the scene. That was the real beast. To get this whole scene to have enveloping smoke to come in and out, with vampires appearing and disappearing to add tension. We had to think of some creative ways. It can be computationally expensive and time-consuming. So we needed to be lean and mean. Timur likes to do lots of speed ramps because of his penchant for stylization. It's cool-looking but it involves volumetric effects that are in constant flux. So we would be getting a new edit every day with minor tweaks on the speed ramps going from two to three percent changes on ramps, and if we weren't able to react to that fast enough, then our iteration time would be too long and they couldn't put our shots in the cut. We needed to be able to turn around a new speed ramp on a shot within hours. So doing a full volumetric smoke solution in 3D was prohibitive. We did some tricks in comp where we would map pre-rendered moving smoke on oblong spheres, which was a big cheat, but augmented with pieces of volumetric smoke."

Fire, which is on the other end of the spectrum, was all CG. Method did full stereoscopic renders for lots of fire shots, working in compliance with Stereo D on the 3-D post conversion.

Method also developed a new system for fire leveraging Houdini that was quick and efficient Click here for the complete 12 image squence breakdown. View a clip of the entire sequence including shot sequence breakdown on AWNtv.

"Almost all of your cheats are discarded because you can't map onto cards," Goux continues. "And so all of the fire is full volumetric fluid renders. That was in parallel with boxcar look dev. We had pretty limited fire capability and took a massive tech development in Houdini, creating a tool that was quick and efficient. You need iterations with this director and this movie."

While looking at a 3D model of the bridge, they would paint pieces of wood where they wanted the fire to come from, and then would start simulating low-res fire off of that. They would emit fire from wherever they painted. In a few hours, they got pretty good-looking fire. Two or three versions a day allowed them to pick a high-res version that would cook over night. Some of the larger shots would take longer.

At the same time, Method dealt with concepts of heat and fuel, when a beam would crash or hit another beam, which would trigger an ember event. If a beam fell higher than a certain velocity, then the chard part in the shader would glow hotter as it rose faster in the air. All of those cues were incorporated into their system.

"It is moody, gritty and messy," Goux suggests. "We hit a threshold with Timur where he told us it was just great."