直接看官方的解释，有点懵.....
还是论坛上的国外友人写的步骤详细，如下：
If you've used Level streaming this is a very similar process to that. Not very hard to pick up on.
- Create your level with your geometry for starters. Then open the Levels panel (Window > Levels)
- Make a sub-level named "Day" or whatever type of lighting scenario you want. Do the same for a second level for "Night" or whatever you'd like.
- In the Level's panel, Right-click on your Day and Night levels and select Lighting Scenario > Change to Lighting Scenario.
- Hide one of the levels for Day/Night.
- In this level add your lights and things needed for day light settings. (In my example, I added a Skylight, Directional Light, and BP_SkySphere).
- Build Lighting for this scenario. With the Night Level visibility turned off (click the visibility eye). You'll get a warning about building with a hidden level. Click Yes, so it'll build lighting with the other hidden and then click the Build in button in the next warning. The lighting Build will now commence.
- Once the Light Build finishes. Hide the Day Level and Unhide the Night level. Add your Lights and setup for the night lighting here. Build lighting and do the same things from step 6.
- Once that completes you now have the lighting scenarios for both set up for use.
- Open the Persistent Level Blueprint and use the Load Stream Level and Unload Stream Level nodes to load and unload the Day/Night levels. The lighting data for each is carried with them.
