What Worldgen Mods Change
Worldgen mods rewrite terrain generation rules: new biomes, new landforms (hanging rivers, giant caves, mega mountains), new structure placement. Key fact: they change seed mechanics — the same seed code generates totally different terrain with them installed, so vanilla seed recommendations stop working. Decide before installing: explore new worlds, or keep existing archive coordinates.
The Big Three Compared
①Terralith (datapack-grade): zero new blocks, 100+ biomes built from vanilla ones — emerald peaks, sacred cherry valleys, lava wastelands. Best compatibility and performance; the beginner's pick. ②Oh The Biomes You'll Go (BYG): 80+ biomes plus tons of new blocks and trees, the most visually lush, with a hard dependency and moderate overhead. ③Tectonic: landform specialist — mountains to Y=300+, deep trenches, no biome rework; stacks with the other two. Combos: Terralith + Tectonic (biomes + landforms) or BYG + Tectonic (lush style).
Surviving New Biomes
New biomes redistribute resources: ①Terralith's Emerald Peaks (Y=250+) hold emerald ore and rare foxes — bring Feather Falling; ②BYG's zinnia plains are dye and honey goldmines; ③desert overhauls cluster oasis villages — structure positions get reshuffled too. Universal advice: bring bed + torches + food when pioneering; don't sleep randomly before finding structures (modded biomes spawn mobs harder at night).
Performance & Compatibility
①Performance: Terralith < Tectonic < BYG; on under 8GB RAM, install just one. ②Worldgen × structure mods (When Dungeons Arise) play nice, but two same-role worldgen mods (Terralith + BYG) fight over biomes unless you add a bridge pack. ③Servers need it server-side only; clients can join vanilla. ④Seeds: after installing worldgen mods, use the author's 'modded seed' recommendations — vanilla seed coordinates are void.