How to pregenerate the Nether, End or a modded dimension

Each dimension has its own chunks, so pregenerating the Overworld does nothing for the Nether or the End. You need a separate task for each one.

Set the dimension

1. Type /pregen gen and press Tab to pick the radius or area option.

2. Continue through the parameters with Tab. Look for the dimension argument. Autocompletion lists the dimensions the world actually has, including those added by other mods.

3. Select the dimension you want and fill in the centre and size.

4. Run the command, then /pregen start.

Choose sensible sizes

• Players usually explore the Nether less than the Overworld. A smaller area is often enough, and the same is true of the End.
• Modded dimensions that are small or have a fixed border don't need a large radius.
• Queue one dimension at a time.

If a dimension doesn't appear

If a dimension is missing from autocompletion, it may not be loaded or registered yet. Visit it once or check that the mod providing it is active, then try the command again.