This is the documentation for Enlighten.
Probe placement
By default, Enlighten places probes automatically around static actors that are lit with probes.
You can't place individual probes manually. However, you can place probe volumes, areas in which probes are placed.
Movable actors are always lit with probes. To make sure movable actors are lit correctly, place probe volume actors to completely cover the spaces where Movable actors are positioned during gameplay.
Add probe volume actors to the same sublevel as the movable actors that will be lit by their probes. Enlighten adds probes to the sublevel which contains the probe volume.
If the sublevel isn't loaded, the probes in that sublevel can't be used to light movable actors.
In case Volumetric Fog is present in your level, probes should be placed as described in the Light volumetric fog page.
Place probes automatically
Enlighten automatically places probes for:
- all the Enlighten Adaptive Probe Volume actors
- all static actors lit using probes
To place an adaptive probe volume:
- Click Modes > Volumes and drag the Enlighten Adaptive Probe Volume actor into your level.
- Use the Geometry Editing tools to adjust the shape and size of the volume.
To avoid creating unnecessary probes, cover only regions of the world in which Movable actors can move.
Enlighten creates probes automatically at the next precompute.
Enlighten automatically removes duplicate probes when Adaptive Probe Volume actors overlap, except when the actors are in different sublevels that use the Blueprint streaming method. To avoid this, split the volumes at the boundary between sublevels, or set the sublevel Streaming Method to Always Loaded.
For more information about streaming methods, see Managing Multiple Levels
in the UE4 documentation.
Place probes manually
Each Enlighten Probe Volume defines the placement of a uniform grid of light probes. To minimize the number of probes, avoid significantly overlapping regular probe volumes. You can control exactly where probes are placed, but you must manually place probes for all actors you want to light them with.
Manually placed probes using Enlighten Probe Volume actors are deprecated and will be disabled in the next release of Enlighten UE4.
You can't mix manually and automatically placed probes in the same world.
To place probes manually using regular Probe Volume actors, in World Settings > Enlighten, deselect Enable Automatic Probe Placement. 
This means Enlighten doesn't automatically place probes to provide lighting for static actors, so you need to place probes manually to provide lighting for all static actors lit with probes.
To place a manual probe volume:
Click Modes > Volumes and drag the Enlighten Probe Volume actor into your level.
- Use the translate, rotate and scale tools to adjust the shape and size of the volume.
To adjust the density of probes in a manual probe volume:
- Select the probe volume.
- In the Details window, adjust the XYZ values under Enlighten Probe Volume > Probe Spacing.
To see the probes in a manually-placed volume, select the volume or enable the Show > Enlighten > Probes visualization.
Visualize probes
To see the probes in the level, enable Show > Enlighten > Probes.
For more information about visualizations, see Visualizations and statistics.