How do games with massive overworld maps like Skyrim or BotW

They only render parts that are in proximity to you.

>>388392764
This
There is a certain distance from/around you that is rendered, besides landmarks far off i.e. mountains.

>>388392732
The world is broken up into cells and they only render your cell and adjacent cells, with some hax to generate things like mountains and hills that you'd expect to be able to see from anywhere.

>>388392732
Did you never play Skyrim since you have to ask? The cell loading is obvious even if you up the loaded cells to 9 from the base of ... 4?

Draw Distance.

>>388392942
Is this how the level design is done, too?

>>388393174
Yeah, there's interior cells and exterior cells with the main difference being interior cells have no terrain and don't connect to anything except through doors (which are glorified teleports).

>>388392732
Multiple level of details depending on distance (both for the geometry and the textures), distant entities aren't loaded (and AI not run), substitute complex distant terrain features or large objects with simpler variants, etc. It's a bunch of tricks and it's probably very complicated. The engine has to use all sorts of data structures to manage all this world data efficiently and load/unload everything at the right time and render the right variants of what is visible. And it's probably not fully automated for the level designers, they probably have a lot of work to do to make sure it all comes out right.

>>388393806
>distant entities aren't loaded (and AI not run)
If their AI isn't run, how can faraway NPCs still have schedules and sometimes travel between towns and stuff?

>>388395116
The schedule with high-level actions can be followed, but the full AI isn't run (since the full map data isn't even loaded, etc).
If you have a few thousands NPCs with simple high-level scripts moving them along pre-established routes (across not fully loaded map areas), this can be loaded and processed at all time, it's not too much. There are a lot of ways to optimize this too if the schedule is deterministic.

>>388393806
Makes you wonder how Bethesda can pull it off (more or less).