Peter Jackson’s epic adaptations of J.R.R. Tolkien’s classic literature provided a new groundbreaking technology to advance special effects. It was during the second installment, The Two Towers, that motion-capture and Andy Serkis were introduced to mainstream audiences.
Serkis famously wore a motion-capture suit while on set and his movements were recorded into a computer program, creating a guide for the digital model used in the film. This allowed the CG character to be extremely life-like, and the practice benefited actors Elijah Wood and Sean Astin as they had someone to act with during filming.
The method is now the go-to way for animating CG characters. Davy Jones from the Pirates of the Caribbean sequels and Caesar in Rise of the Planet of the Apes (also played by Serkis) wouldn’t be possible without it.