What is Lumen

Lumen is a fully dynamic global illumination and reflections system designed for next-generation consoles, designed to bring realistic lighting to next-gen gaming on a budget, serving as the default illumination and reflection system in Unreal Engine 5.

Lumen is based on ray-tracing, or a more optimised, hybrid version of it. It allows for a much more widespread adotion across multiple different graphics architectures without the need for an incredibly powerful (and costly) GPU. Lumen has proven to achieve incredible real-time indirect lighting with surprising accuracy and the emissive lighting contributes to global illumination as well as intregrating GI into the reflections.

It uses multiple forms of ray-tracing including screen-tracing (SSRT), Signed Distance Fields (SDFs), and Mesh Distance Fields (MDFs) in parallel to calculate the global illumination of the scene depending on the objects, their distance from the screen, and certain other factors.

Take a look at the CGHero Supercut for a quick and informative introduction to the abilities of Lumen in Unreal Engine 5.

Not sure where to get started? Check out this beginner friendly tutorial by Polygon Academy on YouTube. Polygon Academy is focused on creating video game art tutorials and sharing relevant industry information based off 11+ years of game industry production experience.