Same geometry. Same materials. Three completely different reads. Lighting is not a finishing step, it is a storytelling decision.
The Scene
I grabbed the City Subway Train scene from the Unreal Marketplace to get started quickly. The core challenge became clear almost immediately: I wanted the outdoor environment visible through the windows while still reading the fluorescent interior lighting. That is a real constraint in photography and rendering — interior and exterior cannot both be correctly exposed at the same time. Depending on time of day and weather settings, one will always be overexposed relative to the other.
Original scene by Dekogon Studios
Unreal lets you compensate by setting light intensities against relative EV values, so you can nudge specific elements back into a readable range. Even so, having the exterior at 1500 nits and the interior at 3000 nits produces a visibly underexposed exterior — technically correct, but not what you would want artistically.
The scene was not set up to physical light measurements, which made sense given it was authored in Unreal 4.17. I did not touch color grading. Everything here came down to Lighting, Exposure, and Camera settings.
Setup 1 - Night-time
Order: Lit, Lighting only, HDRI Skybox
At night, the HDRI is almost irrelevant — you can barely make out the outside through the windows. The brightly lit interior completely dominates, which creates a sense of enclosure: the world outside has disappeared and the train car is all there is. I used correct EV values to set the baseline before adjusting.
Setup 2 - Sunset
Order: Lit, Lighting only, HDRI Skybox
Sunset was the trickiest to balance. The interior is still the dominant light source, but warm directional light through the windows starts competing with it. I used the Sunny 16 rule as a starting point (it assumes full midday sun, so I adjusted down for sunset), then compensated the HDRI intensity to keep the exterior readable. The principle: with the camera exposed for the interior at EV 5, an exterior that reads correctly at EV 10 needs its intensity boosted by 2^(10−5) = 32× to land in the same displayable range. The warmth of the sunset pushing in against the cool fluorescents gives the scene some tension that the other two setups lack.
Setup 3 - Cloudy
Order: Lit, Lighting only, HDRI Skybox
The cloudy setup looked the most washed out. The HDRI brightness sits around 10,000 nits, which is substantial, but soft omnidirectional light kills any sense of directionality. The tinted, dirty glass of the windows also dims incoming light, so I compensated the intensity slightly. The result is flat and even — which is the nature of overcast light. No drama, no shadow, no story. It is the least interesting of the three, but that is the point: diffuse light removes contrast, and contrast is what makes a scene readable.
What This Shows
Each setup uses the same geometry and materials, and yet they do not feel like the same place. The night setup feels enclosed and isolated. The sunset setup feels transitional — somewhere between the world inside and the world outside. The cloudy setup feels institutional, utilitarian, like a line you take every day without noticing.
That shift comes entirely from lighting choices — not from new assets, not from color grading, not from post-processing. These setups are rough and I am not a lighting artist. But the experiment made the principle concrete: lighting does not just illuminate a scene, it determines what story the scene tells.
© 2026 Stefan Groenewoud - All views are my own, not those of my employer.