Guerilla Games is well-known for the Killzone series. FPS games usually restrict the player to a predefined track, which means that developers just placed clouds using billboards and highly detailed sky domes. This technique is widely used in most 3d games right now. This allows to develop “art directed sky” with lots of details. All you need is Photoshop and some artistic talent. However the studio’s new game Horizon: Zero Dawn demanded a different approach.

Horizon is an open world game. You can explore the land and climb mountains. Developers have simulated the spinning of the earth by modeling a time of day cycle. The weather also changes, so naturally the sky has to change dramatically. The sky also takes a large part of the screen, so Guerilla just had to make it aesthetically pleasing. Here’s what they did.