The maximum value for the side length of the /worldborder command is 30,000,000 which sets it to 15 mil. The actual size of the world is actually 30,000,000 x 30,000,000.
When you create a new world, the world border has a size of 30,000,000 (/tp 29999999 100 29999999 to see it).
When you now change the world border to a low value (e.g. 1000) and want to change it back to the original size, it won't work. The maximum allowed size is 30,000,000, which is half of the original size (/tp 14999999 100 14999999).
Linked issues
is duplicated by
MC-63969
Worldborder size 60,000,000 is too small
MC-64519
World Boarder being slightly off the 30mil mark
MC-70076
World border cannot exceed X/Z +/- 29999984
MC-70988
World border does not extend to world edge
MC-72060
World border at 29,999,982
MC-138677
Default world border slightly shy of ±30 million blocks
Comments
Fixed in 14w18a. 60 million now works as a size.
shufboyardee
can confirm, fixed in 14w18a
Correction: In 14w18b setting the worldborder to 60 million (with the center on x=0.0 z=0.0 of course) produces a worldborder at 29,999,984. So we're missing the last chunk before the edge of the world. Since it's missing on all sides that's 32 blocks smaller than it should be. Indeed, setting the worldborder to anything between 59,999,999 and 59,999,968 makes no change but one lower (33 below 60,000,000) and it finally moves half a block.
Oddly, starting a new map and teleporting to the edge (20 short of the edge actually) I find that the worldborder is now at 29,999,984 by default!
Nathan Adams
The 1 chunk difference is intentional so you don't have a sudden "drop" off the edge of the world.
Oh ok. Well that's fine then, so long as there's a reason. I personally like the drop off better (makes the edge of the world seem like the EDGE) but to each their own. I definitely like the change introduced in 1.7 where the ghost blocks past 30 million aren't there anymore. Actually what I really wish is that the land turned into Far Lands just for the last 1km before the edge! The loop, not the stack.
In an unrelated matter, any chance you could weigh in on the "mojang doesn't intend players to fix up villages" stance the mods have taken (in regards to the "blacksmith with door added kills villagers" issue reported here: https://bugs.mojang.com/browse/MC-51196 ).
marcono1234
Dinnerbone, why is there this difference?
From MC-63969
That makes no sense then you should only be able to set the worldborder to 59,999,968 or to the exact 60,000,000
I don't understand why they over-complicate it so much
Fist why should there 1 chunk outside when you can't use it then as you can't build outside
When the limit get changed to a higher value they have to change this again
The worldborder at the 30,000,000 makes more sense as the world closes after this position and then the the worldborder and the world would have the same limit
marcono1234
Confirmed for
1.8.7 I still don't understand the reasons. If you would want the one chunk difference then simply set the worldbordber by default to
worldlimit-16instead of adding some special conditions
Reopening, world border is currently calculated by the following.
sizeInBlocks / 2
With worldborder command set to 30mil max it will only set the border at 15x15 mil
Either the maximum size should be increased or worldborder should be set to handle center to 30mil sizeInBlocks instead of dividing by 2.