Modern Generation

Minecraft 1.21.1 world generation for older Minecraft versions. No new blocks, no new items.

Modern Generation replaces the overworld generator with an exact port of the 1.21.1 one. Your seed gives the same mountains, cliffs, rivers, caves and biome layout as in 1.21.1. It all stays inside the version you play, so walking around you should not be able to tell from the terrain that you are not on 1.21.

What is ported

This is a port of the 1.21.1 algorithms with the same random number generators, not an imitation:

• Terrain: the full density function graph, noise router and terrain splines. That gives jagged peaks, plateaus, windswept hills, deep oceans and wide rivers.
• Caves: noise caves (cheese, spaghetti, noodle caves, pillars, cave entrances), aquifers with their own water levels, and ore veins.
• Carvers: classic caves and ravines.
• Biome placement: multi-noise biome placement with the full 1.21.1 parameter table and the "fuzzy zoom" biome borders.
• Surface: the 1.21.1 surface rules (stony peaks, snowy slopes, badlands bands, frozen oceans, beaches, swamps…).
• Decoration: placed and configured features read from the 1.21.1 data. Ores, trees, grass, flowers, mushrooms, disks, springs, icebergs, lava lakes and snow/ice freezing use the same counts, spreads, heightmaps and biome filters.
• Spawn: the spawn point search lands where 1.21 would put the player.

The engine was checked against a real 1.21.1 server on the same seeds: biomes match 100%, terrain blocks match 100% above y=24, and vegetation density is within a few percent per category.

Differences from 1.21 (limits of older versions)

• World height is 0-255. The rare peaks above 255 are cut. With naturalCaveFloor (on by default) the lowest 24 blocks behave like the bottom of a 1.21 world: caves close off smoothly and the deepest caves hold lava, instead of a flat cut at bedrock.
• Blocks that do not exist in your version are replaced by the closest existing ones, for example deepslate becomes stone, tuff becomes andesite, calcite becomes diorite and powder snow becomes snow.
• Deep ores (diamonds, redstone, lapis…) that 1.21 places below y=0 are squeezed into y=1..15 so the amount per chunk stays the same (compressDeepOres).
• Biomes are mapped to the closest biome of your version for mob spawns, grass color and structures. Terrain and decoration always come from the real 1.21 biome.
• Trees are built with your version's tree generators of the same wood type.
• Plants that your version does not have (for example moss, berries or pink petals) are not generated.
• Structures are the ones of your version.

Usage

• Singleplayer: "Modern (1.21)" is selected by default on the Create World screen. There is also "Modern Large Biomes".
• Server: set the level type in server.properties to modern (or moderngen:modern on versions with namespaced world types).
• Config: compressDeepOres, naturalCaveFloor, lavaLakes, modernSpawn and selectModernWorldTypeByDefault in the mod's config file.

Performance

The 1.21 generator is heavier than the old one. To compensate, new chunks are generated ahead of time on background threads, and the chunks around you load first when you join a world.

On very old versions a moderate render distance (12 or less) is recommended: their own lighting engine struggles above that, with or without this mod.

Community

Questions, ideas and bug reports: Discord

Made by TheKryzzz_. All rights reserved. Minecraft world generation data and algorithms belong to Mojang Studios; this mod is not affiliated with Mojang or Microsoft.