Recent Minecraft snapshots added the possibility to set a square world border that players can't pass through. It is used on the MindCrack server to expand the available area very slowly over time. How can I get the same effect in my Minecraft world?
Video with demonstration of what I'm talking about:
Minecraft allows you to do this directly using different versions of the /worldborder command:
Start with /worldborder center ~0 ~0 to center the future border around you.
Set the border radius to something small: /worldborder set 30.
Make the border grow by a large number of blocks over a large amount of time:
/worldborder add 1000000 10000000
will, for example, add 1 million blocks in all directions over 10 million seconds, i.e. 1 block every 10 seconds.
/worldborder add 1000 1200000`
will increase the world border by one block per day (1200 seconds) for 1000 days.
Repeat steps 2 and 3 (with different numbers) until you're satisfied with the speed.
