ChatGPT is definitly failing any game design course exams in spite of apparently passing law ones…
No, you definitely would need a c++ solution, and it would have to be mixed in to mesh streaming, from a custom peocedural mesh generation system.
Either way, I have several 200km^2 maps running in ue4 - yea at rediculously barely playable 90fps on a 1080.
It’s definitley not impossible to exceed the size you listed.
To achieve those maps, I just picked 8km size, the second to last option to be precise.
The last option is a performance killer.
The second to last, set to 4km seems to perform OK ish.
For the 200km I had to double the components for it to have a decent amount of drawcalls with impostors.
Its something around 625 map tiles from corner to corner - so if you were at the corner and saw the horizon of the opposite corner you’d have approximately 625 draw calls and meshes on top of the level tile you are on with whatever it contains (Those would be double with 4km map sizes).
World origin shifting is fairly aggressive, set to around 200m or so maximum distance.
Overall, it works ok. Its just the engine that is completely trashed by the last 3 years of epic just not giving a s*t about performance and rendering.
To give you a comparison, cryengine works the same scene with similar but differnt setups for distances and maps at 144fps or more on the same low end graphics card.
Even pre ue4.18 - when they changed landscape LODs from being managed by distance to being managed by screen size - can’t compete with it.
The reason you need octree is that the landscape system in unreal is completely 2d.
The labdscape will be rendered even if the player is nowhere near it. Or under it.
An octree system can by nature prevent that - as well as allowing you to load/stream whatever is relevant to the cell you are in and its ajacents.
While it wont fix the issues with the rendering pipeline, doing things right can result in great performance.
Let me see if I can find a link to the procedural thing that was shared here on the forums for you to check…
Here: Procedural Landscape from Shader Graph w/ Geometry Clipmaps BP/C++