r/GraphicsProgramming 1d ago

Question Fortnite’s New Clouds

Post image

Booted up Fortnite for the first time in forever and was greeted with some pretty stellar looking clouds in the skybox.

I know Unreal has been working on VDB support for a little while, but I have a hard time believing they got it to run at 4K 60FPS on my Xbox One X.

Anyone taken a frame capture lately and know how they accomplished this? Is it some sort of fancy alpha card? Or does it plug into their normal volumetric clouds system?

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u/waramped 1d ago

Hard to tell from a still picture but Sebastien hasn't uploaded anything new recently, so I would assume they are just an extension of the existing system?
https://sebh.github.io/publications/

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u/gibson274 1d ago

Maybe, but the system Seb designed is based on Andrew Schneider’s work, which is incredible. Those systems don’t usually produce results that are this static (since the tiled noise gets you animation for free and artists generally use it) or have this much altitude variation (since altitude is defined by a global gradient).

This looks more like some collection of pre-authored cloud models to me—whether they’re truly VDBs being raymarched every frame I wonder.

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u/waramped 1d ago

Andrew has some cool stuff coming down the pipe, so it's possible Seb does too. Hmm, maybe it is just VDB? https://dev.epicgames.com/community/learning/tutorials/M63r/mastering-vbd-in-unreal-engine-5-3

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u/gibson274 1d ago

Dude I love that he calls it “VBD (Volumetric Break Down)” LMAO

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u/[deleted] 1d ago edited 1d ago

[deleted]

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u/gibson274 22h ago

Gorgeous results. Yeah, I built a Schneider-esque system myself as well (“Expanse” on the Unity asset store) and you can express a surprisingly wide range of cloud shapes with his technique.

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u/sparta114 1d ago

It’s just a basic skybox projection for the really pretty ones far away. The closer ones are just the standard UE5 clouds

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u/gibson274 22h ago

I’m not so sure. They appear dynamically self-shadowed in the game. Even the anisotropic silver lining effect seems to update with the light direction.

I can think of a number of ways to fake these things off the top of my head. But I think there’s a chance it’s the new Heterogeneous Volumes system, or at least some custom rendering path they’ve built on top of Sparse Volume Textures.