Robert Downey, Jr. wrote most of his lines down on post-it notes and scattered them around the set so he could read off them while filming a scene. The rotoscoping team simply animated over the notes to remove them from the film during post-production.
According to Writer and Director Richard Linklater, filming was completed in twenty-three days. The animation took eighteen months.
When Bob Arctor (Keanu Reeves) sits on the stage waiting to give his speech to the Brown Bear Lodge, one of the images his scramble suit displays is Philip K. Dick. This is a clever reference to the novel, in which the scramble suit is said to show the likeness of its creator once in every several million permutations.
Philip K. Dick's daughters gave Writer and Director Richard Linklater their father's personal copy of the novel "A Scanner Darkly" when he completed this movie.
This is the highest-grossing digitally rotoscoped animated feature, grossing 7,659,918 dollars. However, being also the most-expensive rotoscoped feature ever made, that figure is lower than the film's cost of 8.7 million dollars.