[UE4] Volumetric Cloud System

LarsLaukens

Hi guys, as my graduation work for college I'll be trying my hand at some volumetric clouds in unreal.
I'll be posting my new progress here, as well as what I've got so far, feel free to comment or ask whatever.



My initial test was to just place some particle systems in a cloud shape. This wasn't bad but it didn't have a lot of mass or shape. Felt kinda like steam.


Next, I tried to make my particles spawn from the mesh so I'd have some more control over the cloud shape, but they only spawned from the shell. Making the clouds hollow. Also still no self-shadowing.


Made a new material based on 3d noise with a world aligned gradient for fake shadows, added some shells to my cloud spawn mesh and changed my particle settings a bit. The clouds are generated based on some layered noises and have actual volume in 3d space. The particles act as a kind of 'canvas' to view the noise.


Here's where I'm at right now.
I layered some extra noise into my diffuse and made some blueprints to spawn and move the clouds. Will be adding different types of clouds and maybe some material trickery to fake lighting during a day/night cycle.

If you have any questions or comments, feel free to leave them

leleuxart

Have you tried the Ray Marching Heightmap function yet? http://shaderbits.com/blog/ray-marched-heightmaps Might be worth looking into, at the very least it's one more example to throw in with your other tests.

There are also numerous cloud Blueprints that might be worth looking into. Maybe you can dissect them for something particular that you need, at least with the lighting. Something like TrueSky or UltraDynamicSky 

LarsLaukens

leleuxart said:

Have you tried the Ray Marching Heightmap function yet? http://shaderbits.com/blog/ray-marched-heightmaps Might be worth looking into, at the very least it's one more example to throw in with your other tests.

There are also numerous cloud Blueprints that might be worth looking into. Maybe you can dissect them for something particular that you need, at least with the lighting. Something like TrueSky or UltraDynamicSky 

Oh wow, I wasn't aware that unreal had ray marching. This looks very interesting to say the least.
I was trying to replicate the cloud system of Horizon: Zero Dawn described here: http://killzone.dl.playstation.net/killzone/horizonzerodawn/presentations/Siggraph15_Schneider_Real-Time_Volumetric_Cloudscapes_of_Horizon_Zero_Dawn.pdf
They use a similar ray marching technique I think.

I'll also have a look at TrueSky and the likes. Thanks for the help! 

FreneticPonies

Ask questions away over here! http://www.gamedev.net/topic/680832-horizonzero-dawn-cloud-system/

Plenty of people doing the same thing professionally, including the guy from Guerrilla Games

LarsLaukens

Had a look at the raymarching tutorials by Ryan Brucks here: http://shaderbits.com/blog/creating-volumetric-ray-marcher
Got some pretty decent results, still have some features to add and some kinks to iron out. I don't really have any experience coding HLSL shaders, so understanding the code came fairly slowly

Basic Volumetric Heightmap


Full Volumetric Material


Not sure how I'd tackle building them up with noises though.