Understanding exterior and interior lighting in unreal engine

Learn all about lighting in Unreal Engine with this article packed full of useful lighting tips. Find out how Maria approaches her lighting, what inspires her, what it’s like working in production as a Lighting Artist, as well as what to include in a lighting art portfolio and much more!

Introduction

Hello there, I am Maria! A Senior Lighting Artist currently working at Splash Damage in London, UK. I previously worked at Crytek in Frankfurt, Germany and Ubisoft Shanghai. I’ve worked with a few in-house engines for my full time job, and I’m a frequent user of CryEngine and UE4. I use UE4 for most of my personal work as it offers me lots of resources for my own lighting design projects. 

Inspiration and Reference Gathering For London Fog

In my spare time I love to watch movies based in the Victorian Era, maybe because it's a completely different culture trend from where I was born. I simply love those dark colour tones with moody British weather. Also I have lived in London for almost 10 years. This piece is actually based on both imagination and real life experience. 

I usually gather ideas for the art direction from Pinterest, and I love the small pictures preview mode, it gives me more of a general idea before I start diving deep into a certain art style. In my opinion it’s a very good starting point to look at the big picture, rather than fall in love with details too early.

In my spare time I also love watching fashion commercials and any other media on top of video games for my personal project inspiration. Looking at other media really refreshes my brain on creative ideas. To me, I believe personal work is all about doing things I genuinely like.

Asset Selection

I always wanted to do a lighting project based on a British movie colour scheme, like the desaturated colour and foggy weather and I found the level Victorian Street by Richard Vinci through the Unreal Engine marketplace. It fits my project really well so I started tailoring my lighting idea to fit the existing environment by Richard.

Pipeline Decisions

Richard’s scene is very well dressed as a starting point so to push the target of gloomy but sunny weather effect, I decided to use a stationary skylight and sunlight. Stationary lights are really friendly when pushing the glossiness effect on materials. The goal is to achieve a really soft but exuberant lighting effect. Instead of using too much post process, I choose to mix the first lighting source (sunlight) and the secondary light source (skylight) with balanced intensity, as that’s how real life lighting works. This pipeline requests good balance on lighting saturation and intensity. I was trained in studio photography, so maybe that’s why I feel this method works better for me.

Execution

Key Lights

My dominant light source is very simple: most parts of the scene are lit by a directional light and HDR textures attached to the sky light. To reveal even more detail for the close-up shot, I purposely chose a very high sun angle so the foreground would mostly be covered by shadow and give me more freedom on lighting design.

Exposure Method

To enrich the depth of the scene, instead of auto exposure locked at 1, I chose to use the manual exposure method, however this will add some difficulty with controlling the light intensity. But understanding the rule of sunny 16 and light ratio helped me a lot. There are some references below for both methods I talked about. Both my post process volume and cinematic camera for screenshots are using manual exposure set up.

Control the Colour

Even though I planned to apply some different blue or green tones for my fill light in the shady zone, with Unreal’s baked secondary light bounce it's easy to get results out of control because the colour of the light rays could be very different. I usually unify my colour temperature on both my post process and my filled light to make sure the colour tone falls into a similar palette after building the lighting. This method works really well for me as I aimed to achieve some classic film colour style.

Using Shadow Planes

Unreal is really sweet for the light bouncing effect, however it's also easy to result in an overlit scene as the light sometimes leaks through meshes. To maintain the nice contrast between bright and dark areas, I used some invisible meshes as shadow planes to stop unnecessary light leaking in the far end area.

Fog

Fog effect is very interesting, frankly it's a fun and painful part. A nice fog effect is based on a well balanced light intensity, between primary and secondary light source and a good set up on the fog itself to work together. 

On the fog set up, view distance and scattering settings, as well as extinction scale are key to having a nice fog effect. I like using volumetric fog in Unreal, as it obeys the density and scattering effect really well, if set up correctly, the gradience upon environment distance could create a beautiful and soft lighting effect. 

 Usually I set up the fog colour based on my directional/skylight and tweak the fog and light colour in the latter stage for good compositing

Interior Lighting For Summer House

Instead of auto exposure histogram, I used a manual exposure setup in the Summer house scene.

I set up the light ratio based on sunny 16 role, for a deep reading please refer this article here by SLR LOUNGE.

I think one thing that is easy to mistake is to try not to overestimate how much bounce light is leaking through a window in real life. Below is one of my references I used when working on my Summer House project. Instead of focussing on how strong the window leaking light could boost the brightness in the room, I spent more time reading how the light actually behaves differently on walls with different diffuse colour. 

In photography and film there is a zone system introduced by the master black and white photographer Ansel Adams. As I was studied photography, the fundamental of photography actually benefits me a lot when doing realistic lighting.

Differences Between Interior and Exterior Lighting
From a lighting design perspective, interior and exterior scenes are actually designed in the same way. They both need a primary and few secondary light sources to provide the visibility.

However, I think that interior scenes have more control for Lighting Artists, as an interior space has more opportunity to use the reflective method to provide more opportunity for lighting variation.

Interiors have windows/walls/stairs and other vertical surfaces, which can easily be turned into a reflector or a bouncing light space. Things are more restrictive when lighting an exterior scene as it mainly counts on the initial contrast, which is created by your primary and secondary light source.

Common Mistakes with Realistic Lighting

Exposure and the final saturation. I think what makes realistic lighting convincing is not only the light set up, it's how the light results in the final rendering.  Regardless of the way it gets rendered, any overwhelming colour or contrast could make the scene artificial or less convincing.

What To Show in a Junior Lighting Artist Portfolio

I think understanding the primary role of exposure, light ratio, colour theory for both painting and lighting are essential points as starters. Instead of playing too much with postprocess or any other add-on effect. Understanding how the light could serve the shape and material the best will benefit whoever willing to join this industry.

Differences Between Junior, Mid and Senior Lighting Artists

Experience of working does count when negotiating titles with employers but I think the main difference is higher level artists are expecting to have better estimation on task planning, problem solving, as well as being able to give suggestions to other teammates. I think with myself I learnt a lot from making lots of mistakes on previous projects. I think an ideal higher level artist should be a mentor who is able to give positive and short suggestions to other teammates whenever they need.

Things Other Artists Should Know About A Lighting Artists Workflow

The standard of physics based rendering is a good start for every department, however I trust each project has its own way to handle textures and materials. The common point I will suggest is understanding neutral diffuse works the best for lighting. Nothing should be too bright/dark or over-saturated. However, this is a common role for normal lighting behavior. It means we can either follow or break it and use it as an advantage depending on the effect we are after.

Best Ways To Communicate With Other Teams

At Splash Damage I work with a really talented team with many experienced artists and I’ve never really met an issue with communication. However if something needs a bit of discussion, the best way is to show the artist the look in the game editor and then we can discuss the best approach.

When Does Your Team Start Lighting The Scene? Pre-Texture or Post Texture?

Depends on the project but as a Lighting Artist we should be confident working with white/grey box blockout. Which is why I mentioned that understanding how to serve the surface and shape with lighting is a primary role as a starter.

Dealing With Stress While Working

Have a plan B and plan ahead. Usually in a studio the pressure does not come from the internal side of the team. There might be some plan change due to production but usually Producers will find the best shuffle plan and they are very professional. However physical stress to your body might be an issue. Make sure to exercise regularly as it’s actually good for your body and mental health in this profession.

Inspiration

Movies, a lot of movies. And music. As a Lighting Artist I don’t really model or texture, but the fun part is that our profession could make the same scene alive in countless ways. I like to take screenshots and watch a movie repeatedly until I remember how the camera moves and how the transitions happen. I took at screenshots from movies I like and analyze how the director of photography uses the camera, how the gaffer set up the lights. I rarely need to look for inspiration on purpose as I love watching movies and animation so much.

Feedback

At work most of my feedback is from the Art Director, for personal work I usually don’t ask for feedback while I am making it because I feel half-way feedback could destroy the original direction of the piece. Also I think a finished piece is worth feedback so it benefits the next one.

Tips and Advice

Keep learning regardless of which level you’re at and ignore all of the negative feedback. When I decided to join this industry I heard many voices about how difficult it is to break the ice and get a job. It is not easy but it's not impossible. So keep learning and practice makes the best.

Go and exercise regularly if you wanna stay for a long time in this industry! The first project you work on might not be 100% what you want but treat it as a way to a better future, observe and learn from your peers. There are geniuses everywhere in this industry.

Outro

Thank you very much for reading and you can find more of my work on my Artstation.