Now, when I say maps, I mean two things:
1. The actual in-game map, or the landscape/worldspace/playable area/gamespace/ whatever term floats your boat.
2. The many and multiple in-game maps used for navigation in actions such as fast travel.
Regarding both questions, I asked on the subreddit https://www.reddit.com/r/daggerfallunit ... p_modding/ about the possibility. Interkama responded:
It's possible to mod the TerrainSampler class to set heightmap however you like per world cell. For example, Nystul's distant terrain mod uses a custom TerrainSampler to create a more exaggerated look. You could do the same thing to sample from a different height map entirely (e.g. transplant Daggerfall to the surface of Mars). I provide a couple of examples in the code using completely flat and perlin noise samplers totally divorced from Daggerfall's own height map.
Interesting so far! But the part I was more interested in came afterwards.
A few things are hardcoded such as world scale, how terrain is smoothed down to place locations, and locations themselves. Location data is read from the end user's game files and currently not possible to modify whole locations or regions (and may never be possible to do this - just to manage expectations). But you could do stuff like change a specific world tile to use a different height map, place custom geometry, add special encounters in the wilderness, and so on. There's probably a lot you can do here with some imagination and tinkering around the edges of what is possible.
So for now, it's unlikely to modify the region wholesale, but you can do a pass on the details, like buildings and such. This is where I'm not sure what the capabilities are.
To give an example of what I'm talking about, let's say I wanted to create an extension of the Alik'r Desert- specifically, adding in the landscape of the desert that is not currently part of the playable world space. (Come to think of it, any extension in any direction could do. ) Would this be considered falling under altering the world scale or modifying locations and regions? Or would the addition of a location/region mean that it would function as long as it doesn't touch the originals?
My latter question about maps luckily requires much less setup to articulate. Would it be possible to replace the maps used in-game with other maps? I don't mean just a retexture- I mean using a resized map, and still having appropriate functionality (as in when I click on the Kingdom of Daggerfall, it recognizes it- even though it's not in the bottom-right corner of the map now for some reason).