UE Tip: Environment Light Mixer

Use the Environment Light Mixer to create and modify common atmospheric lighting components within your scene. It shows the properties of up to five components side by side in a single window, so you don’t have to hunt for each actor in the Outliner.

How can I open the Environment Light Mixer?

From the main menu, select Window > Env. Light Mixer.

Which components can it create?

When a component is missing from the level, the mixer shows a button to create it, and the button disappears once the component exists. New actors spawn at the world origin in the current level.

Component	Create Button
Directional Light	Create Directional Light
Sky Light	Create Sky Light
Sky Atmosphere	Create Sky Atmosphere
Volumetric Cloud	Create Volumetric Cloud
Exponential Height Fog	Create Height Fog

The two lights come preconfigured. The Directional Light spawns as Movable with Atmosphere Sun Light enabled and Atmosphere Sun Light Index set to 0, and the Sky Light spawns as Movable with Real Time Capture enabled.

How do I show more properties?

The dropdown at the top controls how many properties the mixer shows.

Option	What It Shows
Minimal	A short list of the most-used properties per component, such as Intensity and Light Color on lights, or Fog Density on the fog. This is the default.
Normal	Every property except those marked as advanced
Normal+Advanced	Every property

Enable Only show atmospheric lights to limit the Directional Light slot to lights that have Atmosphere Sun Light enabled.

Why doesn’t my Directional Light show up?

The mixer shows one component of each type, and the Directional Light slot only takes a light with Atmosphere Sun Light Index 0. A second sun light using index 1 won’t appear, and if several lights use index 0, only one of them gets the slot. Directional Lights with Visible turned off are skipped as well.