Revamp Exterior Lighting w/ Atmosphere Index + Bonus Tip! –Unreal Engine 4 (4.26)

hey everyone welcome back today we're going to be talking about the atmosphere sunlight index now what the heck is that basically this gives you a bit more creative control over the lighting in your atmosphere for use in exterior scenes so this is not really useful for interior lighting but if you're doing exterior lighting this is an extremely useful tool to know about so let's jump right in so here i've got a simple lighting setup i use the environment light mixer to set up everything correctly if you've never used the environment light mixer before i recommend you check the video i made right here just so you can get up to speed on how i set up my scene right here okay so i'm not going to cover that i'm going to assume you've already set up a basic atmosphere again if you don't know how to set up a proper atmosphere watch this video and you'll be right up to speed okay so now in the scene i've got a directional light i've got a skylight i've got volumetric clouds so it's very important that you have the sky atmosphere in your scene and in your sunlight it's really important to search for atmosphere and you need to make sure that atmosphere sunlight is checked right here all right otherwise this whole tutorial is not going to work for you so let's dig right into what the heck the in the atmosphere sunlight index does so i'm going to select my directional light here over here in the outliner i'm going to hit ctrl w to duplicate it so now we have sunlight and sunlight too so i'm going to select sunlight 2 and in the search details panel right over here we are going to search for index okay so right now atmospheric sunlight index is set to zero let's set this one to one and now you'll see whoa or sky suddenly got a lot brighter why is that let's take a look and let's rotate this directional light a little bit you'll notice we now have two suns in our sky so the atmosphere sunlight index is most commonly used for having a sunlight and moonlight there's a hundred other use cases for this you can have like two suns if you're trying to do a star wars desk like tattooing binary sunset type of look that's just one of many examples of what you can use this for this gives you a lot more creative freedom this can be used in a multitude of ways it's kind of a hidden feature but super useful to know about so one thing to keep in mind is you can only have two atmosphere sunlight indexes okay so by default the atmosphere sunlight index is set to zero and you can have one other see it's zero or one it's binary so essentially you can have one sunlight and one moonlight now i'm going to take this one step further and i'm going to show you guys how to use this atmosphere sunlight index in order to achieve a kind of blue hour lighting as seen here we've got some nice blue light coming in nice blue but there's no direct sunlight right like there's no um the the sun is behind a cloud or it's already set so i want to get the same look but it is tricky to get this look right out of the box but that's a fun challenge so let's get started now before we begin i just want to preface this by saying that this there are a hundred different ways of doing blue hour lighting i don't want i don't want you guys to start commenting like oh well you could have done this or you could have done that like yeah you're probably right there's so what i'm about to show you now is just one way of doing it if you come up with a better solution good for you that's awesome this is just one of hundreds of different ways of achieving blue hour lighting this is what i find gives you the most control but like i said there's more than one way to get there so right now the first thing i'm going to do is i'm going to go ahead and i'm going to hide this new sunlight i just want to have one for now okay now the really nice thing about the sky atmosphere okay is that it's going to give you really nice gradients in your sky right so if i rotate my sunlight here okay i'm going to lower it like this now let's let's look up and we get this beautiful gradient we get this nice bright orange and it kind of cools down and go we get the whole spectrum of colors right we got you know from the cold red at the bottom all the way through yellows and greens and blues beautiful lighting but you'll see uh our scene gets very dark here okay so i want to get this look in unreal but you'll see it it's kind of tricky to get that you don't get that cold lighting like the sun is below the the horizon right now uh but we're not getting any of that cold light so what do we do now the first thing we can do is you know in the post process volume we can change the white balance a little bit so you know because right now everything's feel a little bit warm so i'm going to select my post process volume and i'm going to search for white balance and let's bring the temperature down a little bit okay let's make this a little bit more blue there we go i really want to get that you know it it's actually after sunset i really like the the the gradient that we get in the sky here beautiful beautiful colors but what do we do now like obviously it seems way too dark i'm going to select my sunlight and i'm going to brighten this up a little bit by default it's set to 10 lux i got it to like 50. so we got a much brighter sky uh but that's fine for now and we're starting to get a bit more light in here so i'm going to bump up the value of my skylight up to 2 or three or something just to get a little bit more light in here but you can see so now we're getting a bit better exposure but the colors still don't feel quite right it's still very reddish you'll get that cold blue hour look yet so let's grab our profile volume again and let's change the white balance even more i'm going to bring this temperature way down even more to make it very cold and maybe even i'm gonna shift the tint a little bit as well something like that so now we're getting something you know that's a little bit colder so now things are looking a little bit better but it's still a far cry away from this right so what's next this is where we're going to start using the atmosphere sunlight index to kind of help us out get a bit more directionality get a bit more color in the scene okay so i'm going to go ahead and i'm going to unhide this second light up here which is obviously the scene looks way bad now i'm going to select this i'm going to change the name i'm going to call this um indirect light and i'm going to rotate this all to the opposite side of my main sunlight i'm going to rotate this in direct light here i'm going to rotate it down a bit but now you'll see like i don't actually want two directional lights hitting my scene right i i only want light coming from one main direction and this one is going to be mostly my indirect light so what do we do how do we make sure that that it doesn't actually cast light so select your indirect light here your second directional light and we're going to search for channel by default it's set to channel 0 and i'm going to uncheck it so now by unchecking channel 0 this new light the second directional light is not actually giving out any direct light okay but notice something it's affecting our scene a lot so here's what i'm going to do is i'm going to give this a lot a very strong color i'm going to make this like a very deep blue something like that okay and now you'll see like whoa we're starting to get somewhere here now if i un check this it goes from very you know kind of very almost warm to very bright blue and obviously this is way too bright so i'm going to tone this down so maybe like an exposure of five lux if i bring it to zero and make it five four yeah four it seems pretty good so you might be asking yourself why the heck is a light that's not casting any light affecting my scene so drastically now the reason for that is because of this atmosphere sunlight index okay you'll see it's actually visible but it's only affecting the atmosphere it's not affecting your actual geode it's not affecting the surface of the planet so to speak okay and because our skylight is set to capped real-time capture it's still capturing that bright thing in the sky and thus illuminating your scene accordingly so i'm just going to exaggerate this thing real quick i guess it's a 10 and let's see what happens when i rotate this the other way do you see the pay attention to manny right here okay when i rotate this do you see how the light is affecting him but it's soft indirect light it's not direct sunlight if i had again if i had set my channel back on you'd have direct light but this time it's only the indirect light that's affecting him and affecting the color of our sky atmosphere so i'm just going to leave that here right now let's go ahead and take a look at our reference again now you'll see we're not quite there yet but we're getting close now of course this image has been edited you know and it got some curves adjustment on it's got a very strong vignetting but you know the mood that we have in this image is we're getting close to getting that in the scene so i'm gonna bring this brightness back down to four or something there we go so now in order to bring our image a little bit closer to the reference i'm gonna go ahead and add some very strong vignetting here too normally i would do this in post like in photoshop or resolve or whatever but you know we can kind of preview the same look right here so in a post process volume we're going to type vignetting and i can bring this real strong something like that because look again looking at our reference here the vignette is pretty strong but now the main differences are mostly hue related so i'm going to go ahead and adjust the white balance to just match it a little bit more closely so i'm going to go to the process volume again i'm going to type white balance and let's tweak the temperature yet again and we change the tint a little now you'll see we're we're getting closer we're getting much closer i think i need to tweak the tint a little bit more it's not going to be a perfect match because again this image has been properly edited in photoshop and the tools in photoshop are made for editing photos for them to look good right so really what we want to do is we want to get about as close as we possibly can but it doesn't have to be an exact match so right now i'm kind of happy with the direction this is going this is a kind of a good blue hour feel here but now we're getting pretty close and i think the only thing missing right now is maybe a little bit more directionality so just a little trick here something that i tend to do a lot uh is i'm going to cheat it i'm going to go ahead and add an area light i'm going to go to the play factors up top here and i'm going to choose rectlite and i'm going to bring a big wrecked light in here i'm going to move it above manny have it face down something like this because look the reason why i'm doing this let's take a look at the rocks right notice how the rock have this nice like top lit look to it the sky is still very bright and it's affecting these rocks it's really giving a bunch of 3d shape to these rocks so see that it's the the top of this rock here is not being lit by the sun it's being lit by the indirect light of the sky so i'm gonna go ahead and fake that on our character here lighting in cg is all about cheating and getting a good looking result so now i have a wrecked light placed above him you'll realize it's obviously a way too strong and it doesn't look that good i don't like to have no strong shadows on them so what i'm going to do is i'm going to increase the size of that wrecked light and soften the light on it so so i'm going to select my wrecked light and source width and source height i'm going to set this from 64 to like 512. and now just like that you'll notice this lighting is getting much softer on it we don't have that strong shadow anymore right so i'm going to turn down the brightness from eight to maybe like two three so let's get closer to manny and toggle that light on and off to see what it's actually doing and now this is without the light and this is with the light so it's just adding a little bit of something an extra little bit of of light shining on very soft very subtle but just a little something to get him to pop and just like that we're starting to get a result that is getting pretty close to our reference obviously there's some major substantial differences here such as you know there aid in the water the rocks are a different color the rocks are wet in our reference uh we're missing a lot of elements to really make this match right um the sky is different the clouds are different of course i'm aware that that's not the point of this tutorial we're not trying to basically make this scene we're trying to get a similar mood and really the main point of this tutorial was to show you guys how to use the atmosphere sunlight index creatively for you know unconventional purposes to kind of help you with your lighting get a bit more control over the final look of your scene so one new thing i want to start doing every week is bonus tip so let's say you wanted to change the physical size of your sunlight or your moonlight this is how you would do it so we're going to select our sunlight and in the search details panel we're going to look at source angle okay so you'll see it by default it's at the 0.535 and now look look at the size of the of the sunlight right now now if i increase the value and set it to like 10 you'll see the sun actually gets much bigger i set it to 20 or 50 you'll see this is how you change the size of the assign you can also make it smaller so if i said it's like 0.3 you'll see it's just a tiny little speck in the sky now now one thing to keep in mind is that if you change the size of your sun it's also going to affect the shadows so the larger the sun the softer your shadows will be the smaller the sun the harder your shadows will be so i'm going to take a second to show you this let's pay attention to the shadows of the grass and the ground here forgive the terrible textures this was done real quickly so now let's look at the shadows right here from the gradually they're very sharp so if i select my sunlight and set the source angle down here to 10 you'll see the shadows suddenly get much softer okay so if i hit the 20 it'll get even softer if i set it back down to 0.2 you'll see everything gets really sharp again so like i said the size of your sun directly contributes to how soft or hard your shadows will get so i'm going to be going way more in depth on this topic in a new video that i'm working on that i'm really excited about and i can't wait to show you guys so hit that subscribe button so you don't miss it it should be out in about a week maybe two so stay tuned that being said that concludes this week's video thanks so much for watching guys hit that like button if you haven't already and i'll see you guys next week

Channel: William Faucher

Views: 38,765

Keywords: UE4, Unreal Engine 4, Unreal Engine, Cinematics, 4.26, UE4 4.26, UE5, Realtime, realtime rendering, rendering, CGI, 3D, 3D Artist, atmosphere, atmosphere index, exterior lighting, blue hour

Id: p7HzA0njaFA

Length: 14min 53sec (893 seconds)

Published: Thu Mar 18 2021