This is the documentation for Enlighten.

World properties

The Enlighten world properties affect all actors in the world. You can set the Enlighten world properties under World Settings > Enlighten > Enlighten Settings.

Quality presets

You can apply the Enlighten quality presets to actors in your level to control the Enlighten lighting resolution.

There are four Enlighten quality presets: High, MediumLow, and Background. The default lighting resolution of each preset is appropriate for a human scale world. If your world uses a different scale, you can change the lighting resolution of each preset.

System Parameters

Output Pixel Size

The size of a lightmap pixel in the world.

Cluster Size

The size of each radiosity cluster in the world.

Samples Per Cluster

(Advanced) The number of lighting samples created per cluster. Must be a multiple of 4.

Radiosity Budget

(Advanced) The number of bytes per lightmap pixel used to store radiosity data. Lowering this number reduces file size and radiosity quality. Increasing this number increases file size and quality. The update time and and memory required increases in direct proportion to this value.

Directional Visibility Slices

(Advanced) The resolution of the precomputed visibility data for directional lights. Increase this value to get more accurate bounce from a directional light.

Probe Parameters

Radiosity Budget

(Advanced) The number of bytes per probe used to store radiosity data. The update time and and memory required increases in direct proportion to this value.

Other properties

The following additional Enlighten world properties are available:

System Voxel Size

(Advanced) Specifies the approximate size in world space of the radiosity systems created by the precompute. This is a multiple of the Output Pixel Size.

Enlighten Bounce Distance

(Advanced) Limit the distance that Enlighten radiosity bounce and occlusion are computed. When set to zero (default) there is no limit. This can reduce the duration of the Enlighten precompute in a massive world. Please notice this may cause the Enlighten indirect lighting to be visibly incorrect. 

Enlighten Reflection Boost

Scales the contribution of Enlighten reflections to all actors in the world.

Enlighten Static Albedo Boost

Scales the Enlighten static albedo contribution of all materials in the world.

Enlighten Static Emissive Boost

Scales the Enlighten static emissive contribution of all materials in the world.

Enlighten Volumetric Fog Scattering Boost

Scales the Enlighten indirect lighting intensity for all Light volumetric fog.

Secondary Bounce Scale

Scale to apply to the feedback step that adds the radiosity results back into the input to provide secondary bounce light.

Dependency Included System Distance

(Advanced) Radiosity systems within this distance are used to occlude other radiosity systems when calculating dependencies.

If left at the default of 0, all systems in the world are considered occluders when calculating dependencies. In general, this gives the most accurate result and doesn't significantly impact the precompute time.

If a non-zero value is specified, only systems within the specified distance of a given system are considered occluders when calculating dependencies. In very large maps, it may be possible to reduce the precompute time by choosing an appropriate value. Take great care when choosing this value, because if the specified value is too small, it may significantly increase the precompute time.

Adaptive Probe Grid Spacing

The minimum grid spacing of Enlighten probes generated by an Adaptive Probe Volume.

Adaptive Probe Error Threshold

(Advanced) The error threshold value for adaptive probe placement. Probes are removed if they can be substituted by interpolating adjacent probes without introducing an error greater than this value. A value of 0 generates the largest number of probes and therefore gives the highest accuracy, but at the highest cost. Higher values reduce the number of probes generated.

Disable Enlighten

Disables Enlighten for all levels. After modifying this setting, run a precompute to apply the change. This affects all Enlighten entities, including probe sets, cubemaps and detail meshes. To instead disable Enlighten for a single level, check the Disable Enlighten option in the EnlightenSystemContainer for your scene.

Disable Auto UV Simplification

Globally disable automatic lightmap UV generation

Share Lightmaps Across Levels

Allow meshes with Detail lighting mode to share a lightmap that belongs to a different level. Enabled by default.
If your world is extremely large, uncheck this to significantly reduce the system memory required to run the Enlighten Precompute commandlet.

Probe LOD Distance

The distance at which probe lighting switches to a reduced level of detail. When set to zero, the maximum supported distance is used.

Radiosity Sample Rate

(Advanced) Controls the number of rays to cast for computing irradiance form factors. Usually it is fine to leave this at Medium. Higher settings can alleviate noise issues, but significantly increase precompute time.

Landscape Water Level

When enabled and the Enlighten probe volume is enabled for a Landscape actor, Enlighten probes are only placed above this height.

Dynamic Enlighten Shadow Distance

When real time ray tracing is enabled, the distance at which a Directional Light actor with Cast Dynamic Enlighten Shadows enabled falls back to precomputed Enlighten visibility.

Lighting Debug Mode

(Advanced) Tools for debugging and testing Enlighten indirect lighting.