Meshes in the scene also block indirect lighting, which also produces indirect shadowing.

For example, light bouncing diffusely off a surface picks up the color of that surface and reflects the colored light onto other nearby surfaces - creating an effect called color bleed. Lumen Global Illumination solves diffuse indirect lighting. Also, these features did not fully integrate with other important systems to widely support most features of the engine. Unreal Engine 4 features, like Screen Space Global Illumination and Ray Tracing Global Illumination (RTGI) were not reliable or performant for projects that relied on real-time with a high enough quality. Lumen brings robust dynamic global illumination to Unreal Engine and integrates well with other supporting systems in Unreal Engine 5, such as Nanite, World Partition, and Virtual Shadow Maps. When Lumen is enabled for a project, precomputed static lighting contributions are disabled and all lightmaps are hidden. In each category, set the following to enable Lumen:

Global Illumination and Reflections can be set independently. Lumen is enabled from the Project Settings under the Rendering > Dynamic Global Illumination and Reflections categories. This prevents breaking or changing any lighting paths within those projects. Newly-created projects have Lumen Global Illumination and Reflections enabled by default, as well as their dependencies like Generate Mesh Distance Fields.Įxisting projects converted from Unreal Engine 4 to Unreal Engine 5 will not automatically enable Lumen features. Lumen renders diffuse interreflection with infinite bounces and indirect specular reflections in large, detailed environments at scales ranging from millimeters to kilometers. Lumen is Unreal Engine 5's fully dynamic global illumination and reflections system that is designed for next-generation consoles, and it is the default global illumination and reflections system. Disabling Static Lighting for the Project

Lumen scale distance