 Originally Gollum was set to solely be a CG character, but Jackson was so impressed by Andy Serkis' audition tape that they used him on set as well.A team led by Randy Cook performed the animation using both motion capture data and manual recreation of Serkis' facial reference.Gollum's CG model was also redesigned during 2001, now using a subdivision surface model instead of the NURBS model for "Fellowship" (a similar rebuild was also done for the digital doubles of the lead actors), when Serkis was cast as Sméagol, Gollum's form before he is cursed by the One Ring, so as to give the impression that Serkis as Sméagol transforms into the CG Gollum.