Crazy Horse used 3ds Max for the trains, the FumeFX plug-in for smoke, Synth Eyes for tracking, Photoshop for texturing and surfacing, After Effects and Nuke for compositing.

"The way we constructed the trains is we had about five days on set to completely photo document the entire train," adds co-CG supervisor Luke McDonald. "There were 17 different cars, each one of them being unique, so each one had to be measured and checked twice. There were multiple shots where the train was full-CG and we determined the path of the train and then we determined the path to Robert Stromberg's matte paintings. And there were other shots, where we would take the shot footage of the talent jumping around on the train and just use the people and create a completely new camera for it and do a big pull out or a sweeping move across the train. It was multiple track shot footage and then recreating the cameras from scratch so we could have a much grander camera move on the train."

"We had a window of less than 40 minutes per day where we could shoot with a crazy rig," Graff adds. "And on two of those three days we had to double up because of the different environments. And every time we changed direction, we changed camera angles and ran, ran, ran to get all these backgrounds."

The stampede was a chore as well. It involved a two-day shoot, with three cameras doubling up angles and motions, starting with plates of the lions since they were the most dangerous, followed by the cast and other animal plates. "I'm happy what we pulled together with a pretty small footprint during production and how we got all of these elements that we ended up using and fitting," Graff suggests.

"For the stampede, Paul had the fantastic idea that whenever we shot a single animal, we'd cover it from three different angles, so we could re-use a great take of a lion or lioness and manipulate it three different ways to get three different shots and it worked out really well," adds McDonald.

Bill Desowitz is senior editor of AWN & VFXWorld.