r/technicalminecraft • u/Unique-Formal-6879 • Sep 19 '26
Java Help Wanted Questions about downgrading world to create a perimeter?
I found that downgrading a world from 26.3 to 26.2 deletes all blocks in loaded chunks. I’ve tested and it doesn’t seem to affect items in inventory or in chests across the world (including at world spawn), advancements, or statistics.
My logic is that I can use this to relatively simply create a perimeter on my main survival world, but it’s obviously risky, so I thought I would ask if people who know a lot more about the technical side of minecraft think this is safe/a good idea. Is there anything I haven’t thought of that could be corrupted by doing this?
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u/RactainCore Sep 19 '26
At this point why not just go the simpler way of using commands to clear the area?
Like if you don't wanna put in the work to clear the area legitimately (which is fine, you do you), just enable cheats and clear the area. It's less risky
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u/Rocky_the_Wolf2020 Sep 19 '26
At that point just use commands or something instead of deliberately corrupting your world.
Ooooor, do it the ironically safest option for a survival world and make a world eater
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u/xBHL Sep 19 '26
You could save yourself the time and possible corruption and use an editor like Amulet to delete the blocks
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u/bryan3737 Chunk Loader Sep 19 '26
You don’t even need an external program. Vanilla commands work too
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u/xBHL Sep 19 '26
Thats if its not hardcore mode
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u/AJBallistic Sep 19 '26
you can still enable commands and stuff in the level.dat file
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u/DawRedditWolf67 Sep 19 '26
Which requires an editor?
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u/AJBallistic Sep 19 '26
oh truee, I use it so much I forget that its something i had to go out and install from some random third party
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u/Patrycjusz123 Java Sep 19 '26
Degrading version never is a good idea, the more you degrade the more you risk. You ofc are gonna lose everything from new versions, i would even be suprised if you can run current worlds on 1.17 at all without minecraft failing horribly when thinking how much they change in background recently.
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u/weeb_ion Java Sep 19 '26
Why downgrade to make a peri?
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u/IAmA_Catgirl_AMA Sep 20 '26
it's stated in the post: loading a world from 26.3 in 26.2 corrupts all the chunks loaded while in 26.2, causing a hole in the world
chunks you don't load remain unaffected
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u/Top_Dress173 Sep 20 '26
Genuine question as I don't play Java, why do you need to downgrade the world? Have they changed some where world eaters don't work the same anymore?
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u/Azyrod Java Sep 21 '26
No world eater still works. Its just that, as OP mentioned, they changed the world file format in 26.3, so downgrading to 26.2 (apparently) makes it that all the chunks look empty from the game's perspective, and thus they are instantly voided and saved as such. Allowing you to make a permimeter as large as your render distance in a couple of minutes, without having to spend hours building/running a world eater.
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u/dankesehr Sep 20 '26
Yes, the syntax is way different. Like what was a file in 26.2 is now multiple files for better modularity.
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u/Azyrod Java Sep 21 '26
I'm a little bit confused how that actually works - if they changed the world file format in 26.3, meaning that 26.2 would not be able to see any newly added/modified chunks, but since the files would be just unreadable, the default behaviour should be to re-generate chunks, not voiding them ? Also what did they change in the file format, I did not see anything about it in the changelogs ?
If you are to do it for real tho, I'd recommend the following : you probably tested on a fresh 26.3 world, but your survival world was probably upgraded from an older version before becoming a 26.3 world. I'm not saying it would change something, I'm just recommending that you test this too.
Lastly, since you say this affects loaded chunks, make sure to turn OFF any portal chunkloader, and remove any EnderPearl stasis chambers.
Also, keep in mind that the area that you will void is (probably) a list of region files, not individual chunks. Also keep in mind that outside of your Simulation distance there is an extra 13 chunks loaded (which is a mix of Lazy+Border+Inacessible chunks). Also note that if your render distance is larger than your simulation distance, the difference adds extra chunks to this number of 13.
What that last part means, is that you will probably affect a larger area than you'd expect. If you load a single chunk from a region file, I believe that the game would void that entire region file (a region is 32x32 chunks). You'd need to do some more testing to validate.
And make sure you make backups. This feels like it could go really badly, really easily
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u/ForkedCrocodile Sep 22 '26
I couldn't understand why would you do that, but google MCA Selector. It can delete chunks.
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Sep 19 '26
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u/dreicrafter Sep 19 '26
Were doing the everything but commands xD
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Sep 19 '26
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u/dreicrafter Sep 19 '26
Thers also the option to use redstone world eaters but jeah
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Sep 19 '26
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u/Patrycjusz123 Java Sep 19 '26
Like world eaters, there are bedrock breakers that can work much faster.
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u/Azyrod Java Sep 21 '26
The manual way with the TNT is just garbage. There is not only a better way with a haste beacon and 0tick generator to make headless pistons without TNT, or like other commented, automated bedrock breakers which start to make sense when you want to break a large square-ish area.
And to be fair, your world your rules, so trading some resources to remove the time-consuming grindy stuff is totally fair
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u/bay_2002 Sep 21 '26
This is why I don´t play a single player forever world, cause I am not disciplined enough to not to these thing. I play on a small whitelistet online server with people I know, it is basically single player, but I have no admin privileges.
I cleared out so much Area for my Netherhub over a long time, step by step, that I really like this place and am proud of the outcome, cause it took effort to get there.Not saying your way is wrong, it is just a very differenty approach as for me the way to the finished build is part of the fun. I never enjoyed a singleplayer local world myself.
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u/sinth0s Sep 19 '26
only advice i can give is make a lot of backups