The WorldEdit Singleplayer + SinglePlayerCommand mod is a mod for a single player game that repeats the functionality of the well-known WorldEdit plugin that allows you to quickly and easily change the world. With this mod, you can quickly build huge walls, geometric shapes, replace one block with another, transfer parts of the map to another place and even to another map.
A small list of main features:
You can delete the entire landscape and re-generate it so that it looks natural; You can create spheres, cuboids, forests, etc.; Copy part of the map and paste elsewhere. Copy part of the map and transfer it to a file, and then paste it on another map. You can kill all mobs nearby and remove some objects like arrows; Massively remove the fire on the area. Restore the natural look of the area. Change biome type. Move part of the map to any side. With the help of a compass, you can teleport and pass through walls.