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Here Is How to Set Up Underwater Lighting in Unreal Engine 5

Finn Meinert Matthiesen shared the working process behind the Sci-Fi Underwater Base project and showed how to set up lighting using the Waterline Pro plugin.


Greetings everyone!

First of all, thank you very much again for my second interview opportunity. This is highly appreciated! Since I covered a lot of my bio in my first 80 Level interview, I'll keep the introduction here a bit shorter.

My name is Finn Meinert Matthiesen, and I am currently working as a Lead 3D Artist for Twin-Earth on the indie game CastleCraft, which has been a lot of fun. Together with character artist Alessandro Chiri, I developed the art direction and a reduced low-poly voxel style that is similar to Minecraft’s graphics style, which fits well with the technical voxel sandbox nature of the game.

Before that, I worked as Senior 3D Concept Artist at KARKATER Design Studio in Berlin, where I had the opportunity to work on several AAA projects, including the current title God of War Ragnarök for Sony as our client. Although I enjoyed my time at KARAKTER Design, I missed working directly with video games because the studio mainly specializes in concept art. This led me to switch to Twin-Earth and CastleCraft when an opportunity arose.

Now, I'm almost 15 years into the games industry, nine of these in AAA and almost six years into indie games, starting with spending my first seven years at Crytek, where I worked my way up from Junior to Principal Artist being involved in the production of various games like the Crysis series, Ryse: Son of Rome, The Climb, Warface or Robinson: The Journey.

The Underwater Base Project

The decision to work on an underwater scene was actually quite spontaneous, so I only took an extended weekend to work on it. Of course, in such a short amount of time, it is difficult to create detailed 3D models, so I used many of the 3D assets that I had already created for previous projects. My main goal was to create a scene as quickly as possible that met all the requirements of a reasonably believable underwater environment. So I also used asset libraries from Quixel and free 3D scans from sites like Sketchfab to save time. For effects such as animated fish or lighting, I used Epic Marketplace assets such as the Waterline Pro plugin or the Underwater World Pack.

In fact, I created a fairly large art project in Unreal Engine, in which I incorporated almost all of the self-created and collected assets so that I could quickly use them for future environmental compositions. The project is a real Frankenstein monster, with a size of over one terabyte.

The underwater sci-fi base scene is part of my Core Crusade project – a sandbox container I use for my sci-fi concepts. Although I am not currently pursuing any serious computer game pitch ambitions with it, it serves as an artistic universe for all my futuristic game environments.

I actually used very little material as references and inspiration. In fact, the game Subnautica was an inspiration, as I found its universe and game world to be very well done and exciting and the setting to be fresh. Additionally, I looked at scenes from the game Horizon Forbidden West, classic photos of coral reefs, and some other scattered underwater concept images or shots from the current Avatar movie. However, most of it was creatively improvised, so the flora and fauna would not stand up to scrutiny by a marine biologist.


Since the scene was created in a relatively short amount of time, I solved the composition quite intuitively and improvisationally. The exciting thing about artistic work in games is that you have to create environments that work from different angles and perspectives. Although you always try to guide the player to interesting compositions and vista reveal spots, it is not so easy to guarantee this everywhere. Due to the exploratory nature of games, it is therefore important not to hold too strongly to a rigid compositional idea, but also to be flexible in redesigning. This was definitely the case with my scene.

For example, the entire front area, which dominates the scene, was only created at the end. Originally, I started with the upper part of the central rock formation, whose structures even corresponded to the most basic triangle composition. Only later did I expand the space through various creative associations and add further aspects.


Since I have already explained my workflow more extensively on this topic in my previous 80 Level interview, I will keep it brief. In general, I use classic programs, such as 3ds Max, ZBrush, or Substance 3D for the preparation of 3D assets. Since I had little time for this scene, I imported and created all assets from Sketchfab or Quixel, especially the shipwreck and corals, in a shared library in 3DsMax. There, I cleaned up the meshes a bit and sorted the material IDs, but then imported them directly into the Unreal Engine from there. I also quickly polished some of the textures as well before their import into the project.

Thanks to Unreal Engine 5's Nanite technology, I was spared the effort of setting up LODs. Under normal production conditions, this is a very important step, but since my project was made just for artistic purposes, this feature allowed me to skip that step. The 3D meshes and materials would also be much more optimized and cleaner if it were a final and polished scene for a real game. Nevertheless, the scene still runs with well over 60 FPS in Unreal (well, on my two-year-old trusty NVIDIA 3080 Ti).


I quickly realized that the limited underwater view distance and foggy mood created an opportunity to work more with silhouettes to compose the image. Although the approach was clearly intuitive and improvised, the readability of the structures and areas was very important to me. For example, the concentration of individual coral groups, which were repeatedly loosened up by small gaps or areas with vertically acting sea plants or flatter, shell-shaped structures to calm down things. Reusing one of my previously created spaceship assets as a submarine also made sense, as it resembled the shape of a large sea turtle after a few modifications and thus fit well into the aquatic setting.

To bring the scene to life, I used many particles for air bubbles or underwater dust swirls as well as animated creatures such as schools of fish, jellyfish, or sharks. It was very important to me to depict the dynamic, lively, and constantly moving nature of an underwater world.


When lighting the scene, the Waterline Pro plugin was very helpful to me, as it already has some great sample scenes for underwater lighting. Although I had to adjust these heavily to optimize them for my needs, it gave me a motivating start. I mainly changed the clarity of the water, which is more reminiscent of an ocean area in tropical regions, with significantly higher visibility and calming blue tones reminiscent of a Caribbean diving holiday.

In addition, I placed some key lights to emphasize the semi-hidden futuristic structures without dominating the image. The submarine headlights are quite intense, but I also placed a central spotlight as a light source on the futuristic structure in the central area of the scene, which suggests to the viewer that there is much more to discover in this world. The caustics and sunrays also contribute greatly to the liveliness of the scene, thanks again to the Waterline Pro plugin.

Post-processing-wise, I actually didn't do that much. I'm not a fan of chromatic aberration, so I killed that value right away. There's a bit of a warm grading to counter the very cold and bluish tone, some camera vignettes, and a final increase of the structure detail contrasts. Also, the volume fog starts a bit later to introduce more naturalistic colors at a very close distance. That's it.

Unreal Engine 5

Unreal Engine 5 offers some great features that should significantly simplify the work of designers and artists in the future, even though many of these technologies are still being developed, optimized, and refined. Nanite and Lumen are already very useful graphical features, as they significantly simplify the optimization of environments and thus contribute to faster development of graphic solutions. Especially in the area of pre-visualization of a scene, this is very helpful because, as in the example of my scene, you can work with quite expensive assets and achieve usable solutions and results quite quickly without the computer’s performance suffering.

Usually, environmental graphics are often approached with whiteboxing or greyboxing, i.e., sketchy composition with highly simplified 3D meshes. With Nanite, however, you can also use more complex meshes at this stage, which ideally gives you an even better impression of the final visual approximation of the scene. The lighting feature Lumen allows you to light the scene without being a totally experienced lighting artist so that it can already create a reasonably naturalistic impression in this early stage, especially through the consideration of indirect lighting.

The entire WYSIWYG approach of Unreal, combined with the ability to play and test your own project or scene directly in the editor through blueprints and game code, is great and extremely helpful when it comes to creative iteration quickly and promptly.


The project took me a weekend, from Friday to Sunday. However, I must mention again the abbreviations I used earlier, as I had to create or edit very few 3D assets from scratch, which of course saved a lot of time. In addition, I did not have to spend much time optimizing the scene, which is an enormously important step under normal production conditions, especially to ensure draw calls and performance in a game, as program resources must be reserved for many other operations besides graphics.

In the beginning, adjusting the Waterline Pro plugin was challenging because I had some technical difficulties with shadow casting and rendering distances, but fortunately, I fixed those issues after some research. Apart from that, I stumbled upon some other slight issues, such as problems with the cinematic camera and lighting distances.

Regarding tutorials, I find the YouTube videos by William Faucher, a very experienced artist who should be well-known here at 80 Level, very helpful and charming. In fact, I am also considering giving some insights into my projects in the near future on YouTube or Twitch, but I still have to think about a good concept there, especially with English not being my mother tongue.

What is often underestimated is observing environments outside the 3D art bubble. Many of my ideas did not come from other 3D graphics or games but rather from classic photos of landscapes and architecture or pure concept art. I also wrote a lot about this in my first interview with 80 Level.

In general, I would like to add that although it is a wonderful job, it has not become easier to earn a living with 3D art in the games industry. In fact, my subjective impression is that the conditions have become even more difficult in the past ten years or so. Therefore, I advise beginners to try out 3D art as a hobby before deciding on this path or to try it out if they are already working in another professional field. This way, there's always a safe fallback available in case things become problematic, as the industry seems to be at the moment.

Thank you very much for the kind approach regarding the interview and thanks for being here again! Cheers!

Finn Meinert Matthiesen, Lead 3D Artist

Interview conducted by Theodore McKenzie

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