Guerrilla Games recently held a technical presentation on the Volumetric Cloudscapes of Horizon Zero Dawn at SIGGRAPH 2015. In this presentation, they detail the technology that they have used to render the skies of Horizon Zero Dawn. You can get a glimpse of this in their Time Lapse of the world here.
In addition to this, they also showed some unreleased concept art and screenshots from the game revealing the evolution of Skies in Horizon Zero Dawn.
You can check out the concept and in-game screenshot showing the Volumetric Cloudscape below.
Guerrilla Games then detailed their early concepts and design of the skies in Horizon Zero Dawn. They had a set of main points in mind for the skies in Horizon Zero Dawn.
•Art direct-able•Realistic Representing multiple cloud types•Integrate with weather•Evolve in some way•And of course, they needed to be Epic!
You can see the evolution of their clouds in the screenshots below. All of them were rendered in real-time running on the PS4.
They tried a variety of methods for the clouds of Horizon Zero Dawn including Poly Clouds but eventually had to look for a better method because all of them were unable to evolve over time, which was a requirement for them. Not to mention these method requires some large amount of memory and as a result could go over rendering budget of the game.
This bought Guerrilla Games to their next solution: Voxel Clouds.
Voxel Clouds might look impressive but they also have a very large overhead. Guerrilla Games managed to get these running in the game but it took 1 second per frame to compute these clouds basically rendering them useless for in-game use.
The final solution for them was the Volumetric Cloudscapes and this is intended for the final version of the game. However Guerrilla Games has plans to improve it even further ahead of the launch in 2016. You can check some gorgeous screenshots of these Volumetric Cloudscapes below.
This final solution resulted in a rendering budget of 20 milliseconds for the Volumetric Cloudscapes. They were able to reduce it even further to 2 milliseconds per frame after performing optimization on it, hence using them to render the skies in Horizon Zero Dawn.
Horizon Zero Dawn is currently in development exclusively for the PS4. It was announced for a release in 2016 at E3 2015.
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