In my first post about Maria Yue’s “Lighting for Games in UE5” boot camp, I already explained my approach and the results for the ‘exterior’ lighting assignment I did during the Spring 2023 term at Vertex School. The course focuses on lighting theory and exterior and interior lighting with Lumen in Unreal Engine 5.
This post shows the results of the second ‘interior’ assignment of that course, using the “Polar Sci-Fi Facility” environment (built by 3DBrushwork). We had to come up with a (re)lighting scenario, following a reference board we had to build first.
Moodboard for (re)lighting “Polar Sci-Fi Facility” environment
For this assignment I was inspired by several relatively dark corridor lighting references where warm interior light mixes with cold bluish light from outside. I imagined the sci-fi corridor to be abandoned on a snowy ice planet and went for cold a exterior lighting that is quite harsh compared to the warm interior lighting which is fairly soft. While the exterior light is obviously brighter, it shouldn’t overpower the interior light to much to keep a nice balance.
LIGHTING WORKFLOW
My approach to light this environment was to start with looking for interesting camera angles and compositions, each with a clear focus point supported by the guiding lines of the corridor and the framing of the archway visible in some shots. Working from these camera angles, I started from a completely dark environment and built up the lighting layer by layer, only adding a bit of light with each light added. For this environment I embraced the concept of Auto Exposure using physical values again, but this time I gave it a small exposure range right from the start to balance out how the lighting is perceived in brighter and darker areas.
The first ‘layer’ I did was the exterior lighting and all pools of cold light coming in from the outside. The reason I went for the sunlight direction shown in the images below, is partly because the beam of light coming through the windows in the first image blended nicely with the floor and strengthened the composition, and partly because of the interesting effect it gave on the water pool in the last image. After locking in the sunlight direction, I worked out the desired lighting ratio with the skylight using a pure white plane and the Auto Exposure Histogram. I used shadow planes to prevent undesired sunlight entering the corridor through openings in the roof. For the volumetric fog I wanted to go for foggy weather on the outside, but a fairly crisp lighting on the inside of the corridor. Therefore I kept the global volumetric fog settings quite low in Exponential Height Fog and created local volumetric fog ‘shapes’ to make the fog more dense on the outside. Finally I added some spotlights in the second part of the corridor to fade out the blue pool of light more nicely and I also improved how the exterior lighting entered the corridor via the staircase behind the fence.
The second ‘layer’ I did on top of the exterior lighting, was the interior lighting coming from practical lights with a much warmer color temperature. For this I started with the light generated by the glass column in the last image. working backwards towards the engines near the corridor entrance section by section. The overall strategy here was to use the practical light coming from the glass columns or engines as a base, and to hand place custom light fixtures to create interesting pools of warm light in the corridor to make the overal image more interesting while guiding the eye towards the focus point of each image. Often this included emissive light from the light fixtures, one or two spotlights to increase the effect of the light fixture on the environment and a stretched point light (without shadows) for the effect of light spreading out in the vicinity of the light fixtures. An important tip I picked up from both Maria and Harid during the course, was to be mindful not to add light everywhere, but to balance out the light pockets to guide the viewers eye with dark pockets to create points of rest in the image.
The final images below are high resolution screenshots directly from engine without any additional color grading in external applications.
CLOSING WORDS
My main take away from this assignment is the principle of sculpting with light. This starts with a dark environment and refraining yourself from adding too much light with each light actor you add to the scene. It’s not a bad thing that you can’t see a big part of the environment in the early stages of the lighting process. This gives you the possibility to add light where you want it, while leaving dark pockets to give the viewers eye some points of rest as well.
One thing I haven’t taken into account for this assignment is optimization. Most likely I’ve used a bit more lights for creating this mood then optimal for maintaining a high enough frame rate. So this is a good thing to keep in mind for future lighting practices.