CubicChunks

What CubicChunks does CubicChunks replaces Minecraft's fixed vertical column with a system that loads world sections vertically the same way the game already loads them horizontally. The practical result is a world that can stretch up and down until it hits the 32-bit integer limit, roughly two billion blocks in each direction. The mod runs on Minecraft 1.12.2 with Forge and requires the mod on the server; clients without it cannot join. ## World generation is separate The project description makes clear that CubicChunks itself does not generate terrain above or below the vanilla range. Older releases bundled a sub-mod called CubicWorldGen, but current versions need CubicWorldGen installed separately if you want cubic-aware world generation. Without it you get the compatibility generator, which fills everything below Y=0 with stone. That behavior is documented as the cost of broad mod compatibility. ## Known compatibility limits The author warns that the mod will break many other mods in hard-to-predict ways and that most incompatibilities can't be fixed without changes to those other mods. Specific conflicts are called out: JEID can irrecoverably corrupt a world once certain ID limits are passed. GalactiCraft runs but has major bugs and stability issues, including blocks not rendering above certain heights. WorldEdit is only partially compatible in the 0-256 range; an unofficial branch exists but isn't distributed through official channels. Sponge, Bukkit, Spigot, and similar server platforms aren't supported. MCEdit can't load CubicChunks worlds. ## Practical gotchas A known bug stops players from building above Y=256 on the very first load of a newly generated world. The workaround is to save, exit, and reload. OptiFine compatibility varies by version; the project description notes it works but not with every OptiFine release. The author recommends Forge 14.23.5.2860 for 1.12.2 and advises against using older Minecraft versions unless you know what you're doing. ## Who this is for Server operators and modpack builders who need vertical space far beyond the vanilla ceiling and are willing to test every other mod in the pack for stability. It isn't a drop-in enhancement for an existing world; the incompatibility surface is large and the author treats breakage as expected.