Wonderful Days (Korean: 원더풀 데이즈) is a South Korean animated science fiction film, released in 2003. It features backdrops rendered using photo-realistic computer-generated imagery, comparable to those in the film Final Fantasy: The Spirits Within, along with the use of highly detailed models for some of the backdrops into which the cel animated characters were then animated. However, convincing CGI animation of humans (especially human movement) was not attempted.

The film has been released in numerous Western countries such as the U.S. and Great Britain under the title Sky Blue. These versions have been slightly edited, with the loss of two minutes' running time compared to an original Korean cut. Other Western countries such as France and Finland have kept its original title--which is a Hangul transliteration of the English phrase "Wonderful Days" (it would be rendered in Revised Romanization as "Wondeopul Deijeu").

The backgrounds in the film were shot with traditional motion control techniques, then processed to look like CG. The vehicles were all rendered, and the characters were cel animated.

The film is scheduled for release in the US on Blu-ray disc on June 28, 2008.

Source: Wikipedia