Enlighten is the leading real time global illumination solution for game developers.

Enlighten computes diffuse indirect lighting using radiosity. Unlike other radiosity solutions, Enlighten lets you move and change lights and materials at runtime.

Direct light only (not provided by Enlighten)	Indirect lighting only (provided by Enlighten lightmaps)	Combined direct and indirect lighting

UE4 computes direct lighting and shadows.	Enlighten computes the indirect lighting. Enlighten simulates multiple bounces of the bright sunlight to realistically illuminate the dark areas.	Direct and indirect lighting are combined in the final image.

With Enlighten

Improve your game lighting with high-quality realistic global illumination from many dynamic light sources
Provide lighting artists with instant feedback on their lighting changes, rather than waiting hours for a bake
Give game designers the freedom to create experiences that depend on indirect lighting
No need to work around the limitations of static lighting: Enlighten delivers improved lighting quality and reduced development cost
Enlighten provides instant indirect lighting updates in the editor and in-game when any aspect of the lighting changes.