The mischievous bills were all CG-animated in XSI and composited into live action by London effects shop Lola. According to Lola managing director Grahame Andrew, step one to the counterfeiting was making sure the money looked photo-real. During the shoot in L.A., just like actors would, the animated bills had stand-ins. Andrew and crew took real-life moolah and rigged it on wires throughout the set. "The dollar bills gave us lots of lighting references for what the animated bills would look like," he explains. "They also helped us frame the shot; sometimes it's hard in CG knowing how to frame a background plate, because really you should be concentrating on the foreground, which is actually a CG element." Lola also did some R&D to make the money look realistic as it romped. "This involved building the notes along the creases, so they would fold and bend in convincing fashion, and a little work with the translucency, shadows and density to get the correct feel - all those things everyone does. It's sort of the simple approach. Make them look like real dollar bills and they look like real dollar bills."
In the end the models turned out to be fairly simple, straightforward rectangles with no additional appendages, so they really came to life via Lola's character-building efforts. "Bills, even of different denominations, all sort of look the same, so trying to get different characters into them was interesting," he recalls. "They're sort of defined by their actions." Lola translated the bill corners into "arms and legs" and had the bills interact with various animated or puppeteered props like snack foods and shaving foam, with which the bills cavort.
There was also the Charmin jogger. "We rigged the toilet paper to unravel and again we stuck a lighting stand-in. We also did CG indentations on the roll to make him look like he was really impacting it." And the gooey gum trap that one bill gets stuck in on the way to the car dealer? "Very low-tech. We stuck a little metal rod in some real chewing gum and puppeteered it. Then we removed that and stuck a CG bill on instead." One of the more complicated scenes appears in "False Alarm," when the bills spill out of a bank vault, land on the ground, pick themselves up and run out. "Laurence wanted to make sure that they were still real bills," Andrew emphasizes. "Although they've got character, they're still paper and if they were up in the air they would float like real bills first. The controls you have for a floaty bill are different from the ones for bill that's running along." Lola composited and cleaned up the mad money in Flame and Combustion, and Andrew jokes that the two-month post process yielded "hundreds of dollars."