Pre-Generating and Trimming Worlds in Minecraft Print

If you're running a Minecraft server, especially one with a large world or heavy player activity, pre-generating and trimming chunks can significantly improve performance. This guide will walk you through both processes for Spigot/Bukkit and Forge/modded servers, using plugins like WorldBorder and mods like Chunk-Pregenerator.

What is Chunk Pre-Generation?

By default, Minecraft generates world chunks as players explore new areas. Pre-generating means generating these chunks in advance, so the server doesn’t have to work as hard during gameplay. This reduces lag and provides smoother performance during peak hours.

⚠️ Warning: Chunk pre-generation is CPU and RAM intensive. Run it when no other players are online.

What is Chunk Trimming?

Chunk trimming removes any world data outside your chosen world border. This helps reduce:

• Unused region files
• Server storage usage
• Backup sizes

Trimming won’t delete anything within your set border—it only clears chunks you’ll never need.

 

Requirements for Spigot or Bukkit Servers

To follow this method, you’ll need:

• A Spigot or Bukkit-based server
• The latest version of the WorldBorder plugin
  • v1.8–1.12
  • v1.13–1.14
  • v1.15–1.16
• At least 2 GB RAM for larger pre-gen sizes

 

 How to Pre-Generate Chunks (Spigot/Bukkit)

1. Install the WorldBorder plugin
2. Restart the server
3. Stand at your spawn or centre location (usually 0,0)
4. Set the border:
   • /wb set <radius> for a square
   • /wb set <radiusX> <radiusZ> for a rectangle
5. Whitelist yourself and ensure you're the only one online:
   • /whitelist on
6. Start generation:
   • /wb fill
   • /wb fill confirm

7. Cancel at any time:
   • /wb fill cancel
   • or pause with /wb fill pause
8. Optional: Trim the world to your border:
   • /wb trim
   • Only run this when you’re the only player online

 

 

For Modded Servers (Forge)

Running a Forge server with terrain mods? Chunk pre-generation is even more valuable due to the increased worldgen complexity. You’ll use the Chunk-Pregenerator mod.

Requirements

• Server must be offline
• A manual backup is strongly recommended
• Compatible Forge version: 1.4.7 to 1.16
• At least 2 GB RAM
• Download the correct version of Chunk-Pregenerator

 

How to Pre-Generate Chunks (Modded/Forge)

1. Install Chunk-Pregenerator on your server
2. Restart your server
3. Stand at your desired spawn/centre location
4. Run the command:bashCopyEdit/pregen gen startradius SQUARE 0 0 100
   
   • Replace 100 with your desired radius
   • Use CIRCLE instead of SQUARE to change the shape
5. The mod will show chunk-by-chunk progress
6. On completion, it will give a full summary including total chunks generated and any failures
7. For more commands and usage:
   Chunk-Pregenerator Command Documentation 

Final Tips

• Always pre-gen when no players are online.
• Trim after pre-gen to keep your world clean.
• Don’t attempt this on a weak host—allocate enough memory and CPU threads.
• Back up your world before trimming or pre-generating.