In a recent interview with 4Gamer, Legend of Zelda series producer Eiji Aonuma talked about his work and divulged the creation process of the Wind Waker remake. He said that the process, while difficult, took about six months to complete.
Aonuma talks about some of the hurdles that the developers had to clear when remaking the game. Most of of the hurdles came with the difference in technology between the Wii U and the GameCube, the need to do everything by hand when it came to the cel shading, and manual editing, among other things.
The Legend of Zelda: The Wind Waker HD is now available for the Wii U.
Source: Siliconera