The hero Tooth Fairies were created using hand animation to obtain a defined performance.

Another key digital enhancement was the addition of CG flames on Liz Sherman, a girl who has the ability to control fire. First, actress Selma Blair was body-tracked and geometry was used to drive a fluid fire simulation. Eugenie Von Tunzelmann was the CG lead on the character: "The effects TD would tweak the simulation on a per-shot basis. The fire had to react appropriately to Selma's gestures and her performance, such as any emphasized words. We added fields, collision objects and so on if necessary. Both the fire simulation and the renders were achieved using proprietary software."

Part of Double Negative's involvement also implied creating and animation highly realistic digital doubles for Hellboy, Abe and Johann. Even though Hellboy only had five full CG double shots, the team had to contend with many CG fists and CG tails. The characters were first cyberscanned on set by PCA, and then extensive digital stills were taken by the Double Negative crew. The team also shot reference footage on HD of the characters doing a range of poses and actions. The characters were then all hand-animated. No motion capture was used. "Hellboy flying out of the window at the end of the Tooth Fairies sequence was all-CG apart from the 'Casino' shot," Garrard says. "Abe had one full-CG moment swimming in his tank, and Johann was a CG double when inflating and deflating."

Creativity and Enthusiasm
Hellboy II ended up being one of the toughest shows ever undertaken by Double Negative. The variety and volume of characters and creatures meant that the team was busy from the very beginning. "Conceptually, the movie gave us a lot of creative latitude and it proved to be a very rewarding and creative experience," Butler concludes. "Guillermo is a visionary director and he inspires everyone around him. It is hard not to be affected by his enthusiasm!"

Alain Bielik is the founder and editor of renowned effects magazine S.F.X., published in France since 1991. He also contributes to various French publications, both print and online, and occasionally to Cinefex. In 2004, he organized a major special effects exhibition at the Musée International de la Miniature in Lyon, France.