Enlighten UE5 allows you to choose either Enlighten or Lumen for global illumination.

Lightmass lighting is disabled in Enlighten UE5.

To use Enlighten, in project settings, Allow Enlighten must be enabled, and Dynamic Global Illumination Method must be None.

Enlighten provides indirect lighting only for Stationary lights and Movable lights. We recommend to make all lights in your level Movable.

Remove Lightmass lighting

Before you set up your existing level to use Enlighten indirect lighting, to ensure that there is no stale data left over from a previous Lightmass build, we recommend you remove all existing Lightmass lighting data.

To remove Lightmass lighting:

Under Details > Transform, make sure the Mobility for each light is set to Movable.
In World Settings > Lightmass Settings, click the reset arrow to reset all the settings to the default.
Run Build > Build Lighting Only to rebuild the lighting.

The Lightmass build should complete quickly.

If UnrealLightmass.exe is missing, the lighting build fails and the editor reports an error. This happens if you didn't compile UnrealLightmass.exe when you installed Enlighten UE5.

Visualise Enlighten indirect lighting

To hide and show Enlighten indirect lighting, toggle Show > Lighting Features > Enlighten Indirect Lighting.
Enlighten UE5 4.03 Documentation > Use Enlighten in your project > image2022-7-7_16-41-45.png

If your level uses only Enlighten indirect lighting, you should now see only the direct lighting. To hide and show the direct lighting, toggle Show > Lighting Components > Direct Lighting.

Minimize dynamic shadow cost

Enlighten leaves the computation of direct lighting and shadows to the Unreal Engine renderer. For a Movable light, the cost of Unreal Engine dynamic shadows can be significantly higher than for static shadows.

The cost of Unreal Engine dynamic shadows varies with the configuration of meshes and lights in the level. If you find that the cost is excessive for your level, try one or more of the following approaches to reduce the cost:

For point and spot lights that move, turn off shadows or use Shadow Map Caching (Unreal Engine documentation).
Movable directional lights cast shadows for the whole level and therefore incur the most cost. Where possible, disable shadowcasting per actor.
Depending on the level, general optimization techniques such as merging actors (Unreal Engine documentation) can significantly reduce the cost of shadows.
MegaLights provides efficient dynamic shadows for scenes with many light sources.

Each of the above optimizations requires additional artist time to configure the level. We recommend that you apply each optimization only if you have problems with the cost of dynamic shadows.