UnstableTerrain

Want the terrain experience from Unstable SMP on your own server? That's what UnstableTerrain is made for.

It adds areas like the Great Sea, Mist, Amplified terrain, Far Lands, Furtherlands, Spokelands, Smuggler's Pass, the Underworld, and custom End generation to supported Paper and Purpur servers.

Everything runs server-side. Your players can join normally with vanilla Minecraft — they don't need to install a mod or resource pack.

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Important Notes & Compatibility

Make sure you download the build for your exact Minecraft version.
UnstableTerrain uses version-specific world generation code, so a build made for another version will be rejected instead of trying to load incorrectly.

Platform	Minecraft versions	Java
Paper	1.21.6–1.21.11	Java 21
Purpur	1.21.6–1.21.11	Java 21
Paper	26.1.1, 26.1.2, 26.2	Java 25
Purpur	26.1.2, 26.2	Java 25

Spigot, CraftBukkit, Folia, Fabric, Forge, and NeoForge aren't supported right now.

Already have a world? Existing chunks stay the way they are. The custom terrain only appears in chunks generated after UnstableTerrain is installed.

Back up any world you care about before adding or removing a world-generation plugin.

It's also a good idea not to run another plugin that replaces the same world generators unless that combination has actually been tested.

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Terrain

The terrain is handled directly by the server. Install the plugin, head into new chunks, and the different regions start appearing where they're supposed to.

Overworld

Amplified
Much taller terrain, steeper mountains, and a stronger vertical scale than normal generation.

Great Sea
A huge elevated ocean with deep water, islands, and long coastline transitions.

Mist
Snow-covered terrain with an optional server-side atmosphere that changes the player's time, weather, and view distance.

Smuggler's Pass
A separate island region with its own terrain and structures.

Far Lands

The Far Lands aren't limited to one terrain style. Different areas have their own look:

• Normal
• Negative
• Floating
• Spikes
• Repeating
• Cherry
• Grass Hills
• Sand Hills
• Sand
• Grass Chunks
• Chunklands
• Decay
• Beyond Far Lands Grids

Furtherlands

Past the main Far Lands sequence, the Furtherlands turn into a broken landscape of separated columns, steep islands, and terrain rising above a much lower floor.

Underworld

The Nether has more underneath it.

Deep below the normal Nether, UnstableTerrain generates the Underworld, with its own terrain and biome behavior.

Spokelands

The Spokelands are split into a number of different terrain bands, so you don't just get the same region repeating forever.

• Normal
• Flower Field
• Warts Field
• Waveylands
• Dark Forest
• Fibers
• Bridges
• Rainbow
• Ravenger
• Warped Forest

The End

UnstableTerrain also changes generation in the normal End dimension.

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Mist & Dark Forest Atmosphere

Some regions have optional server-side atmosphere as well. None of this requires a client mod.

Mist

Mist uses personal nighttime, downfall weather, and a reduced send distance to make the area feel darker and more closed-in.

It doesn't keep hitting players with Darkness or Blindness, so you don't get that annoying dark-bright-dark screen pulse every few seconds.

The default Mist view distance is 2 chunks.

You can change it with:

/mistconfig <2-32>