How to Work with Different Times of Day in Sci-Fi Environment with Lighting

Introduction

Hi, I’m Estelle Cozot. I’ve been a Lighting Artist in the video game industry for about three years now. During this time, I worked at Ubisoft Montpellier as part of the cinematic team, contributing to incredible projects such as the Assassin’s Creed franchise (AC Valhalla DLCs, AC Mirage, and AC Shadows), Skull and Bones, Avatar: Frontiers of Pandora and Star Wars Outlaws. I’ve recently started working at Nobody Studio, an outsource lighting company in partnership with Zenimax.

A few examples of my work on cinematics for Ubisoft

Growing up, I enjoyed experimenting with photography, which sparked my passion for creative work. I combined this with my love for video games and pursued game art studies in France. Initially, I focused on environment art but discovered during my master’s program that I truly enjoyed working in the game engine, especially on the final stages, like lighting. Realising this, I focused on lighting and got my first internship at an indie studio called Sentry Games, where I worked on lighting for their first Unity-based game. I absolutely loved the experience, which motivated me to develop my portfolio in this direction.

With guidance from school teachers and alumni, I learned the importance of showcasing a clean time-of-day variation for a scene to demonstrate versatility and lighting fundamentals. I thoroughly enjoy this type of exercise as it highlights the power of lighting in shaping a scene’s mood and storytelling.

Spectrum Galaxy Relight

It’s been a while since I worked on a personal project in Unreal Engine, so I decided to dive back in with something fun and quick to complete. My choice was to create a time-of-day variation. For this project, I wanted to shift my focus from cinematic lighting to level lighting while maintaining strong storytelling and thoughtful image composition as key objectives.

Before starting, I reviewed my portfolio and noticed it lacked sci-fi scenes. To address this, I selected the Spectrum Galaxy scene from Fab. I was drawn to its variety of rooms and the storytelling opportunities provided by the existing level art.

Original lighting in the asset pack

My goal was to incorporate significant variation in contrast and color between different scenarios. To gather inspiration, I browsed ShotDeck, looking for reference images that matched the atmosphere and style of the 3D scene. Specifically, I looked for images with a spaceship or outer space aesthetics that aligned with the vibe I aimed to achieve. I always pick a bit more references than necessary and then select the more coherent ones.

My reference picture board

Once I’ve gathered all my references, I start to analyze what I like about them. For example, how strong the contrast is, what’s the key light, how strong or soft the shadows are. As I do this, I also start to look at the scene in the engine to see what my references can bring to the scene. For example, I really liked those strong casted shadows on the Buzz Lightyear pictures and realized I could achieve that same effect in the scene with a bit of added geometry.

Throughout the project, I’ll always circle back to those references, adding my WIP screenshots next to them to see how they hold up.

Tools

For lighting, I typically use Unreal Engine as it’s the tool I’m most familiar with. For this project, I incorporated the Ultra Dynamic Sky and Ultra Volumetric plugins to elevate the visuals and add more depth to the scene.

The Ultra Dynamic Sky plugin is a versatile and very complete tool that provides control over lots of atmospheric parameters, all conveniently located in one place. The plugin allowed me to quickly try out and experiment with different moods until I achieved the desired look. One of its key features is the ability to create moons and planets without the need for additional assets. For this project, I used this functionality to introduce celestial elements, adding depth and visual intrigue to the sky. These additions not only enhanced the overall aesthetic but also reinforced the sci-fi theme of the scene.

The different planet options

Using the Ultra Volumetric plugin was a new experience for me, and it quickly became a favorite. It generates dynamic volumetric fog volumes with an impressive range of customization options. I’ve always been a strong advocate for using volumetric fog in my lighting work because of its ability to enrich an image by adding layers of depth. It creates a natural separation between planes, which not only improves readability but also enhances the overall composition. For this project, the fog helped emphasize the mood and added a sense of atmosphere that tied the scene together. I also completed the fog with some fog cards from the EasyFog plugin.

As mentioned before, I also used ShotDeck to gather reference pictures. All the different filters and keywords are super useful when you try to find a very specific mood. The “similar shots” tab is also a great tool to find inspiration from different sources and refine a ref board.

Lastly, I used PureRef to keep all the references and WIPs in the same place, it’s easier for me to have everything on the same board to compare both images.

General Workflow

The first step in my workflow is to clean the level, removing any unnecessary lights and atmospheric tools. This ensures a fresh starting point for setting up the lighting. To save time and maintain consistency, I start by setting up one level with the Ultra Dynamic Sky plugin, post-process effects, and other key elements. I then duplicate this base level for each scenario, ensuring that the core setup remains uniform across variations. At this stage, I also configure the Lumen quality settings to optimize the global illumination (GI) and reflections.

Next, I create sub-levels for each lighting scenario and load them into the persistent level. This organization makes it easier to manage different lighting setups.

A lighting scenario set up in the level window

I enable Lumen by activating it in the project settings and ensure that "Generate Mesh Distance Field" and "Use Hardware Raytracing When Available" are also enabled. These settings are crucial for achieving the best possible lighting results, particularly when working with dynamic GI and reflections.

I typically begin by experimenting with the sun at the desired time of day to observe how it interacts with the 3D scene. This helps me determine whether to block or utilize the sunlight as it is. Next, I balance the directional light with the ambient light to achieve the desired level of contrast in the image, whether strong or soft.

Sun angle test

To maintain full control over the final look, I switch the exposure to manual. I configure this in the post-process settings and fine-tune it within each cinematic camera for the final renders. Early in the process, I also add a basic volumetric fog to get a rough sense of how the final image might appear.

It’s time to start refining each lighting scenario! When approaching this kind of variation, I always begin by focusing on a single point of view for look development before expanding to other shots. This method simplifies the process and reduces stress. It's better to focus on a single shot and then move on to the rest rather than constantly going back and forth, trying to make all the scenes work all at once.

Dawn: The goal for this scene was to silhouette the main elements, so I focused heavily on adjusting the sky’s intensity. Since the spaceship has a lot of windows, the sky becomes the primary element that helps me create those silhouettes. Given that the interior is naturally dark, I adjusted the exposure to ensure the sky’s brightness was at the right level to achieve this effect. Additionally, I tweaked the sky atmosphere settings to subtly illuminate the spaceship’s interior, adding depth and visual interest to the scene.

I added several fog volumes and fog cards to introduce depth and lift some of the darker values. By tweaking the fog, I aimed to evoke a sense of mystery and loneliness.

For the tree shot, I relied solely on the sun, skylight, and emissive elements without adding any extra lights. Although the final output is exported renders, I intentionally kept the light count low to reflect a setup that would be practical in a real video game production environment.

Day: When I adjusted the sun, I noticed that it cast appealing shadows in most areas except for the main room. To address this, I used a light blocker (essentially just a plane casting shadow but not visible by a camera) to eliminate direct sunlight in that room. I then recreated the sun’s effect with spotlights to have more control over the shadows being cast.

Light blocker parameter to have it casting shadows while invisible

To further enhance the sense of depth, I added fog cards in the background to help distinguish the main subjects. For this shot, I ensured that each plane of the image had a distinct value, with the ground and roof creating a value gradient.

Explanation of different planes and gradients

This technique adds significant depth and interest to the image. Sometimes, I still find it challenging to achieve this level of value variation, but I’m continually training my eye to identify these issues and find ways to enhance them.

Dusk: In my reference images, I observed soft emissive planes that generated gentle contrast and global illumination (GI). To replicate this, I designed an emissive shader with a subtle falloff to better match the references.

Emissive shader example

The GI in this scene primarily comes from the emissives, so I spent considerable time fine-tuning their intensity and color. During this process, I realized that the ground material produced distracting specular spots due to the emissive planes. To resolve this, I increased the roughness of the material, resulting in more diffuse and subtle reflections.

Night: For this scenario, I relied heavily on emissive shaders, as nearly all the interior GI originates from them. I wanted this TOD variation to be less monochromatic than the dawn one, so I played with secondary lights and emissives to create a color variation. To add depth and clarify the light directions, I incorporated numerous fog cards and volumetric fog volumes.

Lighting-only view mode

I usually tweak the post-process settings immediately after establishing the first pass of sunlight. This helps me get a clearer sense of the final look. In this initial pass, I adjust parameters like color temperature, saturation, and bloom to better align with the desired atmosphere.

To improve the final quality: During production, I frequently switch my screen to black and white to evaluate the image in grayscale. This makes it much easier to understand the contrast in value without the distraction of color. The focus point and light direction appear clearer this way.

How to activate Grayscale filter on Windows with a shortcut

It’s also an excellent method for analyzing the different parts of the image—such as the background and foreground. By doing this, I can easily adjust the light falloff or intensity to prevent the image from appearing as a flat, uniform tone.

For each scenario, I used lighting as a storytelling tool, imagining how a character might move and interact within the spaceship. Adding the robot to the scenes played a key role in this process. Although the robot isn’t performing any specific actions, the lighting guides the viewer’s understanding of its presence and purpose, subtly hinting at its activities.

In the polish phase, I utilized the Ultra Dynamic Sky parameters to refine the volumetric clouds and added a planet to make the sky more visually engaging. This not only enhanced the overall scene but also made the global illumination coming from the sky feel more coherent and logical. I check those parameters to make sure the clouds are always the same each time I make a render.

Volumetric static clouds

To sum it up, this project took me two months to finalize. While the process described above may seem structured and straightforward, in reality, it involved a great deal of iteration, trial and error, and experimentation. Though the final result can always be improved, I’m satisfied with how it turned out and excited to apply what I’ve learned to my next project.

Working on Your Portfolio

I think working on a portfolio piece should remain fun. It’s your moment to showcase your creativity and personality. It’s a great opportunity to step outside your comfort zone by trying something new or focusing on learning a specific skill.

It can be hard to finish a project with work and daily life being exhausting. Sometimes, you just have to put your personal life before work. However I think even if the result isn’t perfect, completing it is crucial to truly learn and improve for your next project.

To achieve this, keep the scope and difficulty of your project reasonable. Along the way, take notes of what could be improved in future projects if you lack the time or skills to address certain aspects now.

Various tips for working on a relight:

• Take regular breaks from your screen to gain a fresh perspective. This helps you shift focus away from minor details and see the bigger picture.
• It’s also okay to abandon some ideas. For example, I initially planned to create more lighting scenarios, but within the given time frame, I couldn’t polish all of them to the same quality. By cutting some ideas, I was able to focus on fewer scenarios and achieve a level of quality I was happy with.
• Take time to observe your surroundings and study photos or real-life lighting to understand what makes it visually appealing. When working in a game engine, it’s easy to get lost in technical details, so it’s important to refocus on what looks good overall.
• Finally, seek feedback. Everyone experiences lighting and can provide valuable opinions. Sometimes, even if your setup is technically correct, the lighting might feel off, such as evoking the wrong time of day or drawing attention to unintended parts of the image. Feedback can help you spot and address these issues.

Thank you for taking the time to read this! I appreciate the opportunity to share my process, and I hope it offers valuable insights to anyone interested in lighting. Huge thanks to 80 Level for featuring this interview!

Estelle Cozot, Lighting Artist

Interview conducted by Amber Rutherford