Hello there @Filippo_B97!
Welcome to UE! And don’t worry, open world lighting can be quite a challenge, even for experienced devs. Checking around the community, there a few points to test here, let’s go one by one.
First of all, since the OG landscape was removed and replaced, you could still have old light data around your scene, which would cause a conflict. To get rid of it, you can force a recapture of sky light data. To do so, look for your current Sky Light actor in the Outliner, select it, navigate through its Details panel, until you find “Recapture Scene”, and click on it.
Also, make sure that “Real Time Capture” is enabled:
Another way to force the rebuild, is to go to the top menu, and apply Build > Build All Levels
Now, since the issue is affecting foliage actors, it’s also worth checking their settings between the Foliage tool. For that, open the tool, look for one of the foliages affected by darkness, scroll down through it’s settings until you reach “Instance Settings”. There, make sure that “Cast Shadow” and “Evaluate World Position Offset” are enabled:
Finally, considering you are working with the open world template, that should include an active Post Process Volume. And since it’s the default one, its probably not set to “Infinite Extent (Unbound)”, meaning any areas of your new landscape that are outside the OG’s range, will behave differently. So, check it’s details, and make sure that option is checked:
Hope these help, and good luck!
