World Gen

130 biomes · 24 structures · 180 decorations

How the overworld is built: 30 stacked biome layers, 7 dimensions, and 122 biomes in the main loop.

Directories

Biomes

130

Terrain, weather, vertical layers, spawn tables, building blocks, and soundtrack.

Structures

Dungeons, towns, temples, pyramids, and other large constructions placed inside biomes.

Decorations

180

Trees, rocks, pillars, mushrooms, houses, and other small objects scattered across the world.

Vertical cycle

The overworld loops vertically. 30 biome layers stack on top of each other, each 256 blocks tall. Climb or dig past 7,680 blocks and you come back to the same sequence.

Your layer is decided by Y. Terrain noise can shift the border up or down by about 32 blocks, so layer edges ripple. Within a layer, your X and Z pick one of the biomes assigned to that layer; each biome in the list has its own frequency weight.

The overworld references 122 biomes. Most sit in the two layers around spawn: 59 in Eden Surface and 16 in Underground Eden.

Core numbers

The sizes that shape every chunk in the overworld.

Field	Value	Meaning
Biome width (X, Z)	32	How wide a single biome pick is.
Layers per cycle	30	Stacked vertical layers before the loop repeats.
Layer height	256	Blocks of Y per layer.
Cycle height	7,680	30 layers × 256. Travel this far on Y and you loop back.
Boundary jitter	±32	Terrain noise shifts layer borders by up to this much.
Spawn layer	6	Y = 0 lands in Eden Surface. New worlds spawn at roughly Y = 54.
Default seed	3	The seed every new save starts from.

How biomes get picked

Biomes do not blend. Every point in the world falls into one 32 × 32 cell, each cell carries one biome pick, and edges get a second pass that cleans up slivers.

Grid	A 32 × 30 × 32 grid of biome picks wraps around the world. Same cell on a different seed still holds the same biome. Y changes the pick because Y shifts which row of the grid you read.
Edge cleanup	Before a cell confirms its biome, the game checks a small ring of nearby cells (five across X, five across Z, three stacked on Y). If any of those disagree with the center, the cell blanks out. Slivers and thin biome patches never reach the world.
Minimum footprint	The cleanup pass is why biomes have clean straight edges and a visible minimum size. A biome will not appear as a one-block sliver next to a larger neighbor.

Layer map

Open biome directory

The 30-layer cycle from top Void down through Naraka. Y ranges are for flat ground; terrain noise shifts the borders by up to 32 blocks either way.

Layer	Y range	Band	Biomes	Notes
24	4,589 … 4,845	Void (top)	1	One empty Void biome. Top edge of the cycle.
22 … 23	4,077 … 4,589	Void	2	Two empty Void biomes.
17 … 21	2,797 … 4,077	Cosmic	17	Moon, Alien, Mars, Island, Digital Space. Stranger variants cluster near the top.
13 … 16	1,773 … 2,797	Order	4	Four Order dungeons stacked vertically.
12	1,517 … 1,773	Spirit Membrane	1	Upper membrane. Closes the celestial zone.
9 … 11	749 … 1,517	Heaven	8	Tube, Ball, Sky Water Cube, Gallery, and four Warp variants.
8	493 … 749	Plastic Membrane	1	Swan biome. Membrane between Eden and Heaven.
7	237 … 493	Aether	3	Aether, Caether, and one Rosary biome.
6	−19 … 237	Eden Surface	59	Spawn layer. Plains, forests, deserts, snow, cliffs, towns. Peak diversity.
5	−531 … −19	Underground Eden	16	Dungeons, city, lotus, pool, farm, sponge, slender, and more.
4	−787 … −531	Rosary	1	Random rosary biome. Buffer before Underground Eden.
1 … 3	−1,555 … −787	Abyss & Silver Membrane	3	Abyss exit from Naraka, then two Memory biomes.
−1 … 0	−2,067 … −1,555	Babel	2	Transitional zone between Naraka and Eden.
−5 … −2	−2,835 … −2,067	Naraka	4	Four fixed Naraka layers. No horizontal variety.

Layer 6 is the spawn band. 122 biome entries total; the table shows band-level counts, not unique biome files.

Dimensions

Seven separate worldspaces. Only Naraka uses the full layered cycle. The other six run single-biome worlds with their own fixed terrain.

Dimension	Biomes	Spawn	Kill plane	How you get there
Naraka	122	~54 (raycast down from Y 100)	—	Default starting dimension. Portal blocks return here from other dimensions.
Pocket	1	Y 17	—	Clonaqualia block (portal).
Creative	1	Y 1	—	Svargaqualia block (portal). Requires Divine world flag.
Firmament	1	Y 1	Y −128	A Hamsa touching the player teleports them in. There is no portal block.
Challenge	1	Y 0	Y −128	Challenge cutscene from a cutscene block.
YHVH	1	Y 1	—	Ending cutscene after collecting all 13 beads.
Debug	1	Y 1	—	Debug portal block. Only available when debug mode is enabled.

Challenge, Firmament, and YHVH reset on every visit. Dying in any of them sends you back to Naraka. Beating YHVH locks the ending out of that save.

What a biome carries

Each biome brings its own block list, its own vermin pools, and its own weather. Every chunk is filled from these fields.

Building blocks	The solid-ground block list. Some biomes use one block; others mix dirt, grass, and foliage.
Random decorations	Trees, rocks, pillars, mushrooms, houses. Each biome sets its own spawn frequency.
Water decorations	A separate pool for water surfaces.
Structures	Towns, temples, dungeons, pyramids. Each biome carries its own weight for each structure.
Day and night vermin	Two independent spawn pools. Spawn rates sit between 0.0 and 6.0.
Rare chunk chance	How often a chunk in this biome triggers rare placement rules.
Weather	Rain in 6 overworld biomes, snow in 13, nothing in the other 103.

Fixed terrain dimensions

Five dimensions and the Eden gallery do not use the normal block list. Their terrain is set by the game itself, so the biome data page shows no building blocks.

Dimension / Biome	Terrain blocks
Firmament	Grass, grass foliage, plants, and the janqualia block. The janqualia block doubles as the return portal.
YHVH	Holy ground.
Challenge	Arena shape comes from the active challenge, not the biome.
Pocket	Flat ground for building.
Creative	Flat grass plane.
Eden — Gallery	A random draw from the full block registry. Foliage, internal, respawn, and heaven blocks are skipped. Layer 6 gallery also places simblock.

The gallery biome draws from the full block registry, skips foliage and hidden items, and drops the respawn and heaven blocks. Simblock only places at layer 6.

World limits

Hard edges, kill planes, and retry rules per dimension.

Horizontal reach	No border. Terrain streams in around you out to 48, 64, 80, or 96 blocks depending on your render distance.
Vertical cycle	Infinite loop. 30 biome layers × 256 blocks = 7,680 blocks per full pass.
Kill plane — Naraka	None. Falling forever is survivable.
Kill plane — Challenge	Dropping below Y = −128 drains health.
Kill plane — Firmament	Dropping below Y = −128 drains health.
Challenge retries	2 extra attempts per session, added in 2.9.3. A third death ends the challenge.
Side-dimension resets	Challenge and Firmament forget all world data every visit.