Doing Lighting Excercises in UE4

Introduction

Hi! My name is Ted Mebratu and I’m a Lighting Artist from Ethiopia, currently based in California. I’ve been into lighting and making cinematics in 3D ever since I was in high school and decided to take it as a serious career path when I started college. 

I’ve been learning and doing 3D and lighting for the past 5 years or so. As I was mainly interested in cinematography, I was learning engines like CryEngine or Unreal so I could make cinematics in a quick and iterative matter and that indirectly led me to a special interest in real-time lighting.

Now, I am working as an Associate Lighting Artist at Ready At Dawn.

One Way to Study Lighting

Personally, I found that studying references and trying to replicate a scene or mood was a great way to learn new things and improve my efficiency in lighting or just environment art in general. That’s mainly how I picked up on a lot of the do’s and don'ts when I first started using Unreal, just by finding random images on the internet that were small and easy enough to replicate and trying my best to do so.

Forgotten Alley Relighting Process

Forgotten Alley relight was a quick exercise to see how I could achieve a rainy/overcast mood with wet/reflective surfaces and rain particle effects and make it look believable. The lighting setup is actually very simple. Basically one dynamic skylight and 4 area lights to fill in all the dark areas. All lighting is fully dynamic with no baked lightmaps. I'm also using ray-traced shadows and reflections. It’s actually amazing how easy it is now to get good results super quick with Unreal’s ray-tracing features. Relighting this scene only took about 30 minutes and iterating was very easy since there are no bake times.

All of these lighting variations took about 10 minutes each to do.

Normally, my first step when beginning a relight is to define the ambient lighting/mood and the main light source. I knew that most of the lighting will be coming from the sky itself so I set up the skybox HDRI and added in exponential height fog. I also added localized fog sheets that have Depth Fade to create a foggy gradient from the sky to the ground, which added a lot to the overall mood.

Next, I just added some dynamic rect area lights pointing down from the sky to fill in all the shadowed spaces and some specular highlights.

Working on Atmosphere

I usually have a specific mood or atmosphere I want to achieve planned out before starting the work. Then, I would look for a suitable scene I could use to exercise that idea. In this case, I wanted to go for an early morning rain setting and this scene fit very well. It was a grimy alleyway with all these doors and closed shop entrances that I could use to indicate the time of day more clearly and indirectly do some form of storytelling. Maybe the day is just getting started and the shops haven’t been opened yet... Having such elements already in the environment helps sell the idea a bit more.

Fog is always essential for creating a more dramatic atmosphere and just overall realism. I used it extensively in this scene since I didn’t have too much to work with in terms of lighting variety.

Color Grading

When color grading, I would usually take the image into external software like Photoshop, apply a LUT from the library as a base and then slowly tweak the levels from there until I get a decent result. For this scene I actually didn’t do any color grading at all, it uses default Unreal's tone mapping settings with no other modifications.

Unreal for Lighting

I think Unreal’s lighting system is very versatile and easy to use. Everything from baking and ray-tracing to fog and atmospherics just works really well together and you’re able to get good results immediately without too much hassle if you know what you’re doing. I’ve been experimenting a lot with the ray-tracing features lately for my relights and they’ve allowed me to make huge advancements in visual quality as well as the efficiency.

Advice to Lighting Artists

I try to keep my lighting setups as clean and simple as possible from the start. It’s very easy to fall down a rabbit hole of throwing more and more lights at a problem until it eventually looks half decent and I’ve run into that issue in the past multiple times. That's why now I initially try to achieve what I’m going for with just 1 or 2 light sources, then slowly build from there once I get a solid foundation to work with.

Collecting and consulting photo references is also a very important part of the process and will help keep your lighting grounded in reality. For me, these relights are a way to kind of unwind and flex my creative muscles a bit so I tend to just go at it off the top of my head. That sometimes can be tricky, though, especially if you hit a creative wall and can’t figure out why something isn’t looking as it should look like and you don’t know what element is missing. That would probably be a good time for looking for some references.

Ted Mebratu, Associate Lighting Artist at Ready At Dawn

Interview conducted by Arti Sergeev