Ultra Fast Pregen (Bukkit/Paper/Spigot/Folia/Sponge)
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Ultra Fast Pregen pre-generates your world much faster than other pre-generators by using every CPU core, so players never wait on chunk generation.
Ultra Fast Pregen (Bukkit, Spigot, Paper, Folia, Sponge)
Ultra Fast Pregen pre-generates your world one batch of chunks at a time in RAM, with structures, caves, features, light and saving on every CPU core, then writes each batch to the region files in one go. The blocks, biomes and light are Minecraft's own.
One jar for CraftBukkit, Spigot, Paper and Folia 26.2, and a jar for SpongeVanilla 26.2. The same tool is also a mod for Fabric, Forge and NeoForge (1.20 to 26.2).
Speed
Intel Xeon E5-2670 v2 (10 cores / 20 threads), 10 GB heap, a fresh world, chunks per second; 1,000 × 1,000 blocks per dimension, and the Overworld over 2,000 × 2,000 blocks:
| Server | Overworld | Nether | End | Overworld, 2,000 × 2,000 |
|---|---|---|---|---|
| CraftBukkit | 119.5 | 244.9 | 435.4 | 139.4 |
| Spigot | 119.1 | 243.7 | 485.5 | 149.3 |
| Paper | 140.8 | 333.1 | 748.1 | 157.4 |
| Folia | 144.6 | 334.4 | 744.3 | 164.5 |
| SpongeVanilla | 142.8 | 253.3 | 553.4 | 192.8 |
A plugin cannot change Minecraft's code, so the Bukkit plugin calls Minecraft's own world generation directly and has no fast terrain path: over 2,000 × 2,000 blocks it generates the Overworld 18 to 31% slower than the mod. The Sponge jar is the Fabric 26.2 mod with a Sponge entry point (SpongeVanilla applies its mixins), so it has every fast path.
Features
- Any radius, square or circle. Set the radius in blocks, take the area from the world border, or center it on the world spawn. Trees along a circle's edge are not cut off.
- Resumable. Stop at any time and continue with
/pregen resume. A run cut short by a server stop or crash continues by itself once the server is back. - Paper and Folia: chunks are read and written through Paper's own chunk storage; on Folia a run goes through the global region.
- Chunks the server holds (around players, force-loaded) are kept when fully generated; part-generated ones are left to the server, and
/pregen resumegenerates them once the server has unloaded them. - Existing chunks are kept unless
skip_existing_chunksis turned off. - API for other plugins. Start and stop runs, follow their progress, and receive every saved chunk.
Commands
| Command | What it does |
|---|---|
/pregen radius <blocks> |
The radius of the next /pregen start |
/pregen shape <square|circle> |
A square, or a circle (every chunk whose center lies within the radius) |
/pregen worldborder |
Take the center and size from the world border |
/pregen spawn |
Center on the world spawn |
/pregen start |
Generate the chosen area around the center |
/pregen resume |
Continue the last run |
/pregen stop |
Stop after the current batch |
/pregen status |
Progress, speed, ETA and memory |
/pregen center [x z] |
Set the center (default 0 0) |
/pregen world [dimension] |
Choose the dimension |
/pregen set [key value] |
Show or change a setting of the config file |
Bukkit servers: permission ultrafastpregen.command for /pregen and the boss bar (operators have it by default); config file plugins/UltraFastPregen/ultrafastpregen.conf. Sponge: operator level 2; config file config/ultrafastpregen.conf.
Tested
- On Spigot, compared block for block with the Fabric 26.2 mod in the Overworld, Nether and End: identical, apart from 10 shipwreck chests in the Overworld stored without water, which get it back when the server loads them. Sponge: identical to the mod in all three dimensions.
- Stopping the server during a run, chunks the server holds, a batch whose saving fails, and the API: tested on Spigot, Paper, Folia and Sponge. In the game with a player on every server.
- Not tested yet: worlds with a plugin's chunk generator, other plugins' block populators, together with other plugins.
Requirements
| Server | Minecraft | Java | File |
|---|---|---|---|
| CraftBukkit, Spigot, Paper, Folia | 26.2 | 25 | ultrafastpregen-bukkit-26.2-15.1.jar (in plugins) |
| SpongeVanilla (API 20) | 26.2 | 25 | ultrafastpregen-sponge-26.2-15.1.jar (in mods) |
Players do not need anything. It uses all CPU cores, so it is best run before players join; lower threads by 1-2 if players are online.
Link and Manager
Two more tools that work with Ultra Fast Pregen 15.1 or later. Each is one jar that is also a Bukkit and a Sponge plugin: put it next to this one, in plugins on Bukkit servers and in mods on Sponge.
- Ultra Fast Pregen Link: generates the world outside the world players are in, on this server or on others, then adds only the chunks the world does not have yet. Folia can be a host but not a client, and has no
/ufplink pregen. - Ultra Fast Pregen Manager: a web page inside your server. Pick an area on a map, press Start, and watch the run. It also shows the machines of a Link network and which of them generates what.
Source, test results and API: https://github.com/Pongsapat3791/Ultra-Fast-Pregen · License: LGPL-3.0
Ultra Fast Pregen (Bukkit/Paper/Spigot/Folia/Sponge) Team
