Java Edition 21w37a

21w37a is the first snapshot for Java Edition 1.18, released on September 15, 2021, which adds new generation features from the 1.18 experimental snapshots and fixes bugs.

World generation

 * Caves


 * Completely overhauled.
 * Now stretch down to Y=-59.
 * The caves now generate in 2 layers of different stone bases depending on the depth.
 * The layer above Y=0 is made up of regular stone.
 * Stone transitions to deepslate from Y=0 to Y=-7.
 * Deepslate now completely replaces stone from Y=-8 to bedrock.
 * Certain types of ores and structures still generate in the deepslate layer, as well as tuff.
 * Dirt, diorite, granite and andesite do not generate in this layer.
 * Dripstone Caves and Lush Caves now generate naturally underground.
 * Contain aquifers, bodies of water with different heights, independent of sea level (Y=63).
 * Aquifers below Y=0 sometimes generate with lava instead of water.
 * Improved old caves to blend in with the new generations of caves better
 * New noise caves, coming in 3 forms, "cheese", "spaghetti" and "noodle".
 * The original caves still exist with their generation slightly tweaked to better blend in with noise caves.
 * Cheese caves have large stone towers stretching from the bottom of the cave to the top.
 * Very large, often large enough to fly with an elytra.
 * Abundant with springs, aquifers and ores.
 * Spaghetti caves are long, thin caves that have small aquifers and are more similar to original caves.
 * Noodle caves are thinner, squigglier, and more claustrophobic variants of spaghetti caves.


 * Mountains
 * Come in 6 sub-biomes:
 * Meadow
 * The lowest layer of a mountain that look like a flowery and colder plains, with an aqua grass color and dark blue water color.
 * Contains grass, tall grass, dandelions, azure bluets, cornflowers poppies, daisies, alliums, and dead bushes.
 * Unlike the, it does not contain sweet berry bushes.
 * Only rabbits, donkeys and sheep spawn in this biome.
 * Grove
 * Reminiscent of a snowy taiga with snow blocks instead of grass blocks.
 * The second lowest layer of a mountain.
 * Covered in snow, snow blocks, powder snow and is filled with spruce trees.
 * Rabbits, wolves, foxes, sheep, pigs, chickens and cows spawn in this biome.
 * Snowy Slopes
 * The second highest layer of a mountain.
 * Covered in snow, snow blocks, powder snow and ice.
 * Only rabbits and goats spawn in this biome.
 * Lofty Peaks
 * The highest layer of a mountain which will only generate if the mountain is high enough.
 * Tends to generate sharp peaks.
 * Generates when surrounded by medium biomes such as plains, forests, birch forests and dark forests.
 * Covered in snow, snow blocks and stone.
 * Only goats spawn in this biome.
 * Snow Capped Peaks
 * The highest layer of a mountain which will only generate if the mountain is high enough.
 * Unlikely to generate sharp peaks.
 * Generates when surrounded by colder biomes such as taigas, giant tree taigas and snowy tundras.
 * Covered in snow, snow blocks, ice, and packed ice.
 * Only goats spawn in this biome.
 * Stony Peaks
 * The highest layer of a mountain which will only generate if the mountain is high enough.
 * Tends to generate sharp peaks.
 * Generates when surrounded by warmer biomes such as deserts, jungles, savannas and badlands.
 * Covered in stone and gravel without any snow.
 * Only goats spawn in this biome.


 * Ore veins
 * Long and rare ore formations.
 * Copper ore veins mixed with granite and raw copper block generate above Y=0.
 * Iron ore veins mixed with tuff and raw iron block generate below Y=0.

Technical

 * Debug screen
 * Added two new lines: Multinoise and Terrain.
 * Only appear if the dimension where the player is uses the multi-noise biome source type.
 * Multinoise lists the parameters used at the player's position in order to place a biome. C is continentalness, E is erosion, T is temperature, H is humidity and W is weirdness.
 * Terrain lists values related to terrain generation.

General

 * Tags
 * Spawners now have a new tag, which lets players override the spawn rules of the spawned mob.
 * In the tag, players can specify, which indicates the highest block-light the spawners will spawn mobs at.

Blocks

 * Enchanting Table
 * Now emits a light level of 7.
 * Cave Vines, Kelp, Twisting Vines and Weeping Vines
 * Will stop growing if shears are used on the tip.
 * Sculk Sensor
 * Have been re-added to the Creative Mode inventory.

Items

 * Bundle
 * Have been re-added to the Creative Mode inventory.
 * Can once again be crafted.

Mobs

 * Axolotls
 * Now only spawn in lush caves.
 * Now has it’s own mob cap.
 * Evoker, Pillager, Vindicator and Ravager
 * Will not attack baby villagers anymore.
 * Goat
 * Now only spawn in snowy slopes, stony peaks, lofty peaks, and snow capped peaks biomes.
 * General
 * Hostile mobs will only spawn in areas where the light level is equal 0.
 * This change only affects block-light and not sky-light.
 * Zombie, skeleton, spider, and cave spider spawners now spawn mobs up to block-light level 11.

World generation

 * Overworld
 * Now uses the multi-noise biome source type.


 * Lush Caves and Dripstone Caves
 * Now generate naturally underground and inside hills or mountains.
 * Azalea trees now generate above lush caves.


 * Deep Warm Ocean
 * Now generates naturally.


 * Beaches
 * Beaches are generally wider.
 * In some places there is a chance where no beaches generate at all, to provide some variation.


 * General
 * Terrain generation is now independent from biomes, with biomes adapting to whatever terrain they happen to generate throughout.
 * This allows for natural variation in the terrain of any individual biome, both in terms of shape and elevation.
 * For example, forests and deserts could form up on a hill without needing a special biome just for that purpose.
 * This additionally allows for smoother transitions between biomes.
 * Terrain is now smoother and more extreme.


 * Sub-biomes
 * Wooded hills, birch forest hills, tall birch hills, taiga hills, taiga mountains, gravelly mountains+, desert hills, desert lakes, shattered savanna plateau, swamp hills, dark forest hills, snowy mountains, snowy taiga hills, snowy taiga mountains, modified jungle, jungle hills, bamboo jungle hills, modified jungle edge, giant tree taiga hills, giant spruce taiga hills, badlands plateau, modified badlands plateau, modified wooded badlands plateau, and mushroom field shore biomes no longer generate naturally.
 * As a result:
 * Water lakes are now incapable of generating in any desert biome.
 * All deserts are now eligible for village and desert pyramid generation.
 * All taigas are now eligible for village and outpost generation.
 * All swamps are now eligible for swamp hut generation.
 * All dark forests are now eligible for plains clearing generation.
 * Shipwrecks and buried treasure can no longer generate within the bounds of mushroom islands.
 * Whether any of the biomes listed will be re-added is currently unknown.

General

 * Height limit
 * Has been increased to 384 blocks, expanding 64 blocks up and 64 blocks down, with 319 being the limit upward and -64 being the limit downward.


 * Clouds
 * Raised cloud level from 128 to 192.


 * World types
 * Removed the Large Biomes and Amplified world types.