Tips for Sky Atmosphere & Fog - Unreal Engine 5 (& UE4)

Hey everyone, welcome back. It's great to see you. The topic of today's tutorial is going to be all about how to set up the sky atmosphere to drastically change the look of your scenes.

So with just a few sliders, we can go from having something that looks like a regular average sunny day to something that looks like it's a totally different planet.

So with that being said, let's jump right in and get started.

All right, so now that we're in Unreal, what we're going to be looking at in this tutorial works in both Unreal Engine 4 and Unreal Engine 5.

I'm using UE5 here, but don't worry, the process is exactly the same in UE4.

The scene I have right here is a scene that I created during my last livestream. I'll put the link to it in the description below.

So for starters, we're just going to relight this completely, and I'm going to show you how you can completely change the mode of your scene with just a few sliders. So let's get started.

So the first thing I'm going to do is I'm going to use the Environment Light Mixer to establish a default sky atmosphere system.

So you'll find the tab right here. If you don't have the tab right there, you can go to window and then open ENV light mixer.

If you don't know how to use it, I made a tutorial about it right here. I'll put the link to which in the description as well.

So go check that out if you don't know how to use the environment light mixer. So I'm going to go into lit mode so we'd see what we're doing.

And in the environment light mixer, you're going to want to create skylight, create atmospheric light zero, and create sky atmosphere.

Now you'll notice everything's still kind of black. That's normal. Don't worry. Don't forget to toggle your directional light.

And your skylight should also have real-time capture turned on.

So you'll notice now that if we rotate our directional light, you know, the sky will also change accordingly depending on how high the sun is in the sky.

So as the sun gets closer to the horizon everything kind of gets a nice warm yellow color. And this all feels very believable.

This feels very earth-like. Pretty realistic in the sense that you know all the light it's colors that we're used to seeing.

But what happens if we want to take it to the next level and we really want to just change the mood the entire mood of our scene here?

I'm going to get out of camera view here and show you guys a few sky atmosphere settings that you can change to totally change the look of your scene.

So zooming out here, let's take a look at our sky atmosphere in the outliner here.

And in the details panel, let's scroll down all the way to where it says atmosphere, my right here.

Okay. And if you'd play with or play around with the my scattering scale,

you'll notice that things start looking very different, right?

Like you'll notice like, Whoa, almost feel like a kind of a desert storm or something.

This is a very interesting look that it gives with just a very simple adjustment of the slider.

Another setting you can change is the Rayleigh scattering. OK, so we're going to play around with this right here and you'll notice suddenly like, whoa, things look totally different.

So if you play with these two sliders, both the Rayleigh scattering scale and my scattering scale, you know, you can definitely achieve some very interesting looking sunsets, things that you wouldn't be able to find by default.

So these are two of my favorite settings to play around with.

You also have my absorption scale as well that you can play as well here. So there's a few sliders here that you really should know about.

Obviously, I'm not here to tell you that there's a right or wrong answer to use here. You need to be the art director yourself.

But the point of this video is to make you aware that these sliders exist.

Now, keep in mind, you also have an art direction box at the bottom here where you can kind of tweak the color of your sky a little bit more, as well as having a few other settings for a height fog contribution and a bunch of other settings.

So I really just want to make you aware of this whole section down here of the sky atmosphere.

And now the last thing I want to talk to you guys about is how to use the exponential height fog in conjunction with the sky atmosphere.

So I see this misused all the time, and I'm going to show you how to use it properly. So we're going to go up here in the place actors menu.

We're going to create a height fog.

And you'll notice obviously things get way too bright, really

over the top but this is fine for now I just

want to show you notice what happens if I rotate the Sun below

the horizon okay notice how everything it

should be black but it's not like notice how everything is still very

bright blue why is this the reason for this is because the exponential height fog is an additive process okay and you'll notice here we have a few settings to change.

So going to again to the details panel we want

to change the fog in scattering color here make this black and scroll down a little bit further and you want to change the directional in scattering color and make this black as well.

And now notice how the fog will correctly change color and inherit the color of your Sun depending on how high it is on the horizon.

So now if we move the Sun below the horizon everything goes

black as it should okay so now

your fog will actually take the correct color of the sky or