Creating a Custom Map / Overriding Worldgen

[Spookyrus]

I've been searching for hours trying to find a tutorial on this topic to no avail, so I figure I'll just ask directly.

How does one create and use a pre-made, non-random world for a mod? Say you want to create a special challenge map with a set layout. How would you accomplish this?

Also, is there a way to have the game decide between a few possible pre-made maps when the world is created, or is it more practical to have all the maps in a single world and give players a way to teleport between them?

[Terra B Welch]

Theres a couple mods that can help with custom map creation, one being an empty map mod the other being a mod called simple map editor.

Heres simple map editor.

https://steamcommunity.com/sharedfiles/filedetails/?id=1848571133&searchtext=editor

and heres empty map

https://steamcommunity.com/sharedfiles/filedetails/?id=2122550867&searchtext=empty

@penguin0616 also made an online map editor, either they can link it here or if they don't mind me doing so I can edit this post to include a link.

Currently for custom maps though I don't think there's any way to modify nodes(the things that determine sandstorm, ruins, lunar, etc.)

[Spookyrus]

I was thinking of using simple map editor but I haven't seen empty map before, thank you! Those should be really helpful.

This only tells me how to make the map, though. I still don't know how to force that map on worldgen through a mod.