This is the documentation for Enlighten.

4. Add light sources

Let's add a light source to create the effect of direct sunlight.

  1. From the Modes menu, under Lights, drag the DirectionalLight class into the level. It doesn't matter where.

    This creates a DirectionalLight actor which illuminates the level.

    If Unreal Editor displays a "LIGHTING NEEDS TO BE REBUILT" warning, don't worry.

    This is because the DirectionalLight's Mobility is set to Stationary. We'll change this in the next step.
  2. With the DirectionalLight selected, in the Details tab, under Transform, set the Mobility to Movable.

    This tells UE4 that the actor can change in game mode, and must have dynamic lighting and shadows.
  3.  When you make changes, Enlighten updates the lighting instantly in the editor. To see this in action, use the Rotation tool (E) to rotate the DirectionalLight actor.
  4. Use Ctrl + Z to put the light back to its original position.
  5. To add a sunlight color to the light, in the Details panel, under Light, click the Light Color property and choose a pale yellow from the color picker.
  6. To complement the sunlight, add another light source to give the effect of light from the sky. In the Modes tab, in the search bar, type "enlighten".
  7. Drag the Enlighten Texture Environment class into the level. It doesn't matter where. 
    This creates an Enlighten Texture Environment actor. This is used to create the effect of scattered light from the sky (as opposed to direct light from the sun).
  8. In the Details panel, under Environment, set the Brightness to 0.5. The lighting is updated instantly with your changes.
  9. To give the light a blue-sky color, click the Environment Color property and choose a pale sky blue.

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