Need help with landscape edges

I wasn’t sure if this question belongs to Rendering or Content Creation, but I finally decided to try here.

I’m making a fighter jet game. Not much fighting actually, the idea is to hit targets on the ground by dropping bombs. Most of the physics and the basic game engine is done, so I’m starting focus on map/level design now. I don’t have a solid plan yet, but I’m thinking different environments for each level. Like Middle east desert, Pacific ocean with tiny islands, jungle etc. I’ve started with the desert map, and I’ll simply see where it goes from there.

The landscape is made out of an importet height map. Like this:

What’s a bit awkward is that the landscape obviously just…ends. You can clearly see the edges even in the game from a good distance, especially when you gain some height considering you’re flying a jet after all. And since it’s a desert it’s pretty hard to think of things to cover the blunt edges with. It wouldn’t make sense to frame the desert landscape with skyscrapers in an attempt to disguise the edges.

I could use some help figuring out how to disguise the edges of the landscape.

I tried using Atmospheric fog. But atmospheric fog is designed to fog the horizon, which moves with the plane of course. What appears to be a foggy distance at the center of the map will be crystal clear when you fly closer. I could have wished there was some kind of volumetric fog for this purpose, like a wall of fog/smoke. I suppose that could be done with particle emitters if I wanted to, but given the size of the map that would be ridicilous in terms of performance.

Another option is to simply scale the landscape so much that the edge would be far away enough to appear less obvious. Meaning what, ten times the size of the actual playable area of the map? Is that even reasonable with performance? What is the reasonable max size of a landscape? UE already complains my map is so big it needs a Light Importance Volume, which sounds to me I’m already pushing it?

So, what would you guys do about this? I’m going to face the exact same problem with the Pacific ocean design, how do you make a water surface appear like an endless ocean in all directions?

check out world composition and origin re-biasing, physics get funky @ around 20 Km from origin, origin re-biasing will get you around that for a single player game, it’s not compatible with multiplayer. there’s no real limit to size of your map ue4 is just telling you that lightmass importance volume is a good idea, which is a given for any size map