Setting Up Lighting in UE4

Florent Tunno gave a talk on his recent relighting experiments in Unreal.

Florent Tunno gave a talk on his recent relighting experiments in Unreal.

Introduction

Hi everyone, my name is Florent Tunno. I am a young graduate Environment and Lighting artist from France.

5 years ago I decided creating environments for video games would become my full-time job. I worked on various student projects during my 5 years of study, from 2D mobile game to full PS4 3rd person game. I quickly focused on modeling, texturing and lighting because I wanted to graduate being able to produce a complete environment by myself.

My most recent projects are focused on lighting because that’s what I want to do in the video game industry.

Re-lighting

I chose these scenes because I wanted to improve my lighting skills. As all learning scenes from Epic are almost 100% ready to use, I used the scenes to focus on lighting, composition and post process.

It wasn’t my first attempt at lighting using Unreal Engine 4 but I still learned a lot doing these projects. Relighting scenes are a very effective way to train, learn and improve saving a lot of time not having to create all the assets and textures.

Principles

There are two ways you can look at lighting for video games: a technical one and an artistic one.

For the artistic part (the one I prefer to be honest), lighting plays a critical role in setting the mood for any level but it also makes other artists’ works shine! Lighting can totally break a scene and that’s why it is so important. Even a simple grey box lighting can set a mood or highlight some level design elements. When a player plays the game you worked on, he will feel differently depending on the lighting of the area. Colors, luminosity, effects (fog, volumetric lights…) will affect how the player feels about the environment he is evolving in.

Technically speaking, it’s a matter of UVs settings, lightmap resolution, memory constraints, and guiding the player through the level (you can’t have a too bright or too dark area, or the player will feel weird about it).

With the technology available today, you have different ways to light a video game. You can use dynamic lighting, that allows you to have real-time interaction with lights, but at a performance cost. The other way consists in using a full or partial baked lighting. This method allows you to use Global Illumination: you can tweak how light bounces on the environment, shadows, and light propagation are more accurate, smoother, more realistic overall.

[Screen dynamic vs Baked lighting]

When I do relights, I usually start by gathering references from games or movies, but also from photos! Because modern engines are able to replicate how light and materials react, like in real life, it’s essential for any video game artist to understand how it works. You have to understand how PBR workflow works, why does a light ray bounce on an object, what light temperature can bring to your scene… Luckily for me, I’ve learned how light physically works in high school, so it wasn’t completely new for me when I got interested in lighting for video games.

When I am done gathering references I kill all existing lighting from the scene I am relighting, that includes deleting all lights and Lightmaps.

Lighting isn’t just putting lights into your scene, tweaking the settings, bake and voilà. You have to prepare your scene to be “Lighting ready”.

First, have to start placing Lightmass Important Volumes, Lightmass Portales and boxes or spheres reflexion capture. Then you have to set up all your meshes lightmap size. UE4 has a great tool called Lightmap density. It’s really helpful to get the right lightmap size for each of your assets.

Then you have to think about level design and environmental storytelling. I’ll talk about it later.

Finally, tweaking Lightmass settings is a must. Depending on your hardware and your level size, you’ll have to tweak each setting to get to a fine result. If it’s a portfolio project, don’t hesitate to bump up the settings!

Lightmass settings from the Bunk scene

To begin with, you have to know being a lighting artist means that you have to mix technical and artistic skills together.

You have to remind less is more. Don’t try to use a bunch of different light, start with a directional, look how it interacts with your scene, then add point or spotlight to highlight details, or indicate where to look at when people will take a look at your work.

Lighting a scene takes time, don’t rush it, as I said before, Lighting can break your scene but it can also make it shine!

When you start learning lighting, tweaking settings can be boring at some point but the more you’ll do it, the less time you’ll spend on it. In the beginning, you’ll search for long minutes where to look at, but with practice, it will become natural for you.

Don’t forget creating a video game involves faking a lot of things. Don’t hesitate to bump up values or add more lights to an area if you think it seems too dark. Lighting for video game isn’t only a matter of realism, you have to remind that people will play your game. You can’t have a very dark area because it’s “realistic”, the player has to see where he is going. And if your scene is too dark, players won’t have the possibility to take a look at the awesome work your team produced!

A good point to start at learning lighting for video games is to watch Epic’s awesome tutorial videos:

Then you can start to watch other videos produced by Lighting artists such as Kemal Gunel‘s one:

Materials

Thinking about materials and tweaking it is a great way to get better. You have to know how PBR works because material roughness will directly interact with your lighting. A reflective material will give a radically different result compared to a matte one.
It’s a matter of balance. Too much reflexion will give the feeling that you are evolving in a world full of mirrors but too less will give a too flat result.
Tweaking roughness from each material allowed me to make the floor less shiny
With a good lighting, you can make players experience a “Wow effect”. You’ll help players experience feelings about the game they are playing. Is the scene meant to be sad, joyful, surprising?
An important part of lighting for video games is to think about Level Design and Narrative Design. As a Lighting artist, your job is to guide the player through the level. A nice and bright part of a room will be the place to go for the player, but what about the darkened part of the room back there? Is there a secret hidden in it? As I said in the beginning, lighting sets a mood. For example, we’ll take a look at The Last of Us. At the beginning of the game, the tones are turned to blue, Joel is a cold old guy who lost everything. But when you go further in the game, warm colors and warm lighting appears when he starts to get closer with Elie. Lighting is a part of environmental storytelling, don’t forget it.
I wanted to indicate to the spectator he has to go to the door at the end of the hallway, so I used material reflexions to have a red area jumping out of the blue.

My advice as a Junior

Don’t hesitate to reach to other artists, they will give you feedback and it will help you be a better artist. I want to thank Kemal Gunel and Alexis Argyriou for their advice.
Thanks to 80.lv and Artem Sergeev for giving me the opportunity of writing this. It was a pleasure to be interview by the website which helped me learn so many things during my scholarship!

Florent Tunno, 3D Lighting/Environment Artist

Interview conducted by Artem Sergeev

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