A new unnecessary nether portal is created in the overworld when returning from the Nether

Bug still exists in version 1.14.1

After some testing it look to me, like the area where existing overworld portals are detected is to small.

Usually when leaving nether it should devide nether coordinates by 8 and check a 1024 blocks area arround coordinates in overworld if already active portals are there.

Possibly the detecting area is much smaller than 1024 for some unknown reason what results in creating new portals, cause the existing portals are not found.

I made some tests, and I can still reproduce thiss bug in the latest release version.

So the bug still exists in version 1.14.2

I discovered one new effect in this Version, some portals are generated in a differnt rotation than the portal in the nether.
I am not sure if something was changed or if it is yust the result of other inactiv portal-frames which block the space at the exit location.

To my knowledge, this would happen because of a discrepancy in how the game checks for portals. It does not check for portals within 1024 blocks; instead, the radius it checks is 128 blocks. However, in the nether, coordinates are multiplied by 8. This means that building a portal in the overworld within 1024 blocks of another will not create a new portal in the nether. However, creating a portal in the nether more than 16 blocks away from another portal will result in a new overworld portal being generated. The portals are generated at corresponding locations, and the now match up, meaning the portals link to each other fine.

However, say you had one portal in the nether, and then built another portal in the overworld less than 1024 blocks away, but more than 128 blocks away. The closest portal within 128 blocks (when going from the overworld to the nether) is now the original portal. Both overworld portals link to the same portal in the nether. If you destroy the first portal you built in the overworld, the second portal in the overworld and the only portal in the nether are now linked. Going to the overworld to the nether won't cause a problem, as when your coordinates are divided by 8, the new location is within 128 blocks of the portal in the nether, and you are placed at that portal. Going back, however, will cause a different behavior: you will create a new portal. This is because when your nether coordinates are multiplied back by 8, there is no longer a portal within 128 blocks of that location in the overworld.

This is a very long and complicated way of saying that this most likely works as intended.

Am I understanding this correctly that it happens every time? Not sure if I can create a new issue... I have a similar problem of a newly created OW portal, but it doesn't happen every time. My two original linked portals work as expected most of the time, but every once in a while, it spits me out at a new portal that's always in the same spot, that I break every time.

@ @unknown

You are right, for me it happens everytime when I come back to overworld.

But I think, if you have a similar issue what only occoures somethmes I still thing the reason for this is similar.

@ @unknown I understand what you try to tell, but I think its still a wrong behavoir.

Because in my world ALL Portals in Overworld in a 1024 Blocks area arround the first portal are linked to the same target portal in the nether.

So it would be logic that the nether portals should search in this 1024 area for portals and link to the closest.

What I see as bug is, that Overworld Portal successfully find its partner portal in the nether, but the netherworld portal is not finding any partner portal.

@Jim: Could you provide your coordinates? Maybe you have an edge case where one side of the portal is still in range and the other is not...

Sure!

OW: -1513/-1514 58 -1181

N: -174 43 -139/-140

The random new one has popped up a few different orientations but is within a block either way of -1376 34 -1121

seed is -2207802877571978244

When I tested it after the first time, I went in and out every which way and side and it worked fine. The only different thing that first time was I had a splash potion of weakness on me from curing a villager. I figured I somehow confused the inner maths, but then it happened again later.

Hm, the x coordinate is almost an edge case: -174*8 is -1392 and it would find portals in a distance of 128 from that - which covers the range from -1264 to -1520, so your -1513 is very close to the edge (and it could well be that only a distance of 127 is still in range and 128 is already out).

Edit: According to the source code, coordinates from -128 to 128 (inclusive) are checked.

Your x coordinate in the nether is the same for both sides, but I don't know what coordinate exactly is used (the one from the portal or the one of the player), so maybe it depends on where you are standing when entering it. The z coordinates are nowhere near an edge case.

Edit: According to the source code, the player position is used, so it really may depend where exactly you are standing in the portal.

I assume that if you moved one portal a bit closer to the other (1 block in the nether or 8 blocks in the overworld), they should link reliably. As for the "bug" itself, my understanding is that it is probably working as intended (search distance always being 128 in the destination dimension), even if that leads to an asymmetric linking. At least it's always been like that...

Edit: "It has always been like that" is probably no good reason, but this behavior is used for one-way fast travel, so changing it now would break existing content.

@@unknown I cannot see any situation where a changing of the search radius to 1024 in overworld would break anything.

If somebody likes to be linked to a portal in a 128 range this would still work like now, cause if multple portals are in range, the closest matching portal is choosen as link partner.

So the only thing what would be changed, that no useless portals are created.

Your said it yourself, nether distances must be multiplied by 8 do get the correct overworld values.

So it would be logical that portal search radius in nether is 128 and search radius in overworld should be 1024 (128 multiplied by 8)

@Radon8472 You are right because the one-way fast travel relies on a 2nd portal in the overworld already being there (where the "useless" portal would be created otherwise) - so this would not break. I am however not sure if there are other usecases that rely on this behavior - but it's not my decision anyway 🙂

The issue still exists in version 1.14.3

> I cannot see any situation where a changing of the search radius to 1024 in overworld would break anything.

Searching 64 times more area for a valid portal would be extremely decremental to the server performance....

@unknown you could be right.
But if that is the only problem, they could add a new segment to the region-datfiles.

E.g. instead of checking all chunks block by block, they could store the portal locations in a separate array, and update this everytime when a new portal is activated or disabled.

With that behavoir searching for portals would be very fast, maybe it would even improve the current performance.

The issue still exists in version 1.14.4

In 1.14.3 I was able to prevent this bug by leaving the nether in the direction I was facing when arriving in the nether.

My overworld and nether portal are facing east/west and when entering the nether portal form the east side I come out at the original portal, when entering from the west side a new portal gets created.

My seed is -9060493524218898299 and the world is running on a server and was created before 1.14. The region my original portal is standing in is a 1.14 region because I build the portal in a 1.14 village. The nether region was most likely generated before 1.14.

@unknown can you add the locations of your Portals in your world ?

OW: 581  52  3798/37999

N: 56  98  487/488

When leaving the nether by entering the portal from the west side a new portal gets created somewhere around 438  70  391

The z coords should be fine, but 56*8+128=576 is smaller than 581, so it doesn't connect on the way back. The difference is very small, tho, so maybe entering in a certain way and standing a little closer towards the coordinate that is just enough seems to have worked before (since it uses the player coords)...

I discovered a report (see MC-164368) about a very similar bug, where the coordinates not seem to have this 128 to 1024 block problem, but it generates new portals too.

So maybe this 128 block therory issnt fully correct

I think, Mojang changed something with Nether portals for 1.15 to make lookup faster. They might be caching the coordinates of already found portals and maybe there still is a bug. I read something similar a while ago which was supposed to be fixed, tho. I don't remember the issue number, tho. The 128 block thing is not just a theory, it is in the (1.14) code - it always looks at every block in that range to find a portal block (in the target dimension) and then takes the closest one.

So or so, it would be a bug if it is realy implemented in the code like this.

The game logic says overworld coordinates are Nethercoordinates multiplied by 8. what means the overworld lookup distance should be 1024.

By the way, how can you be sure how the code is implemented ?

Do you have a decompiled version of minecraft ?

Yes, I have, like many others here. I just use Forge for that because it's easy, but there are other methods as well.

I don't know if it's a bug or intentional (probably, for performance reasons - checking 1024x256x1024 blocks is much heavier than 128x256x128). It is surprising behavior for sure, especially for new people, so I agree that it should be changed, whether it's a bug or not (unless there really is a useful usecase for this). Maybe the performance improvements Mojang did for 1.15 (maybe caching or keeping all portal coords stored) are a first step into that direction. Maybe it will be done in 1.16, the Nether Update - but that's just speculation and I think this is not the right place to discuss that since this is a bugtracker and not a discussion forum (and I don't want the Mods to smack us with a portal block or so ^^).

I agree, we should stay in the correct topic.

But I thing, If they would currently plan to change anything, this tickout would be assigned to a Developer and/or to a fix_version.

I think we can agree that this is a confirmed bug, because you noticed that the wrong detection distance is part of the current sourcecode.

But I saw in a video of the minecon, that the MC-developers thing that the portal locig a realy complicated piece of code.
So I think they stay away from this Ticket until more players vote for this.

And I see some other tickets with a similar problems, so I realy hope more players will vote for this thicket in the next time.

It is not a bug for me, just surprising behavior. And I never said it was wrong in the code, I just stated how it is implemented. Whether it is a bug or WAI is for Mojang to decide. Many of the other tickets are actual bugs, like new portals being generated right next to an existing one, even being within range, happening after changes had been made for 1.15 (not necessarily related to this ticket, maybe just performance optimizations like storing portal coords so the search is faster, potentially allowing a bigger search radius). The issue here is debatable and since my opinion doesn't help the developers, I won't post any more comments, because this is not a discussion forum.

Is this still an issue in 1.15 pre-release 6 or later?

Yes. At least 1.15.1

Can you confirm for 1.15.2?

Confirmed for 20w06a

Tested and Confirmed for versions

• 1.15

• 1.15.1

• 1.15.2

I can`t see any change in the behavior of the portals during my tests.

p.s. sombody should update the affected versions for this ticket

@[Mod] violine1101 why do you change the ticket status to resolved ??
Multiple people confirm that this problem is NOT resolved

The report is closed as 'awaiting response'. When the reporter comments, or a moderator changes it back, it will go back to 'unresolved'

Sorry, this was stuck in Awaiting Response for far too long for some reason. Reopened it now.

Hey guys is there any way for someone to explain how this works.. i created an issue, now it says its resolved.. people are commenting but not saying anything just putting the word duplicate and a link to another issue... its very confusing and my issue isnt sorted or explained.

@@unknown  duplicate means there is already an issue that handles your problem.

You can follow (and vote) now the main issue and share helpfull informations until the problem is solved.

So will this be fixed in the next update??
Extremely annoying problem.

Found this bug too. I hope Mojang sees this soon. I guess it also is used as an exploit to farm obsidian easily

Up to version 1.16.1 the bug behavior is not changed.

Since Version 1.16.2 the Bug even got worse.

Now even when entering the nether new portals useless are created (in my world new portals are created at N 22 79 15 instead of connecting to the existing portal at N 127 72 34)

This breaks all long distance travel routes.

And leaving the nether via the correct portal at N 127 72 34 still creates useless portals in the overworld.

It seems that the Portal connect distance in the neather is decreased instead of increasing the search distances in the overworld.

This affects Versions 1.16.2 and 1.16.3

Why is the status of this ticket changed to fixed ??

It is not fixed, it is even worse in 1.16.3.

So please FIX this issue.

It wasn't fixed it was resolved as Works as Intended @unknown

I don't see why they changed it to fixed either. I'm still getting this bug with newly generated portals in 1.16.3

People, don't pay attention to the Status above. It is still UNRESOLVED. Please acknowledge the issue exists

Is it this change some do new portal get created? https://youtu.be/l1H2-Zi45Gs

They has change so is important what side you go in a portal and is more important you link it to right cords. 

But if it still make portals even if you have set it on right cords, it is a bug. 

Has not try it self yet, if it happens even if it linked up. I hope mojang fix I or hope spigot/paper can fix it. 

To bring some more infos into the nature of this bug;  I gather the Known infos:

The reason for this bug seems to be the area in that portals in "the other side" are detected when you switch from nether to overworld or from OW to nether.

The Expected logic is

• When you travel from Overworld to Nether the game checks if there are existing portals in the nether in a range of 128 blocks arround the corresponding portal coordinates (Overworld coordinates devided by 8)

  • If there is one or more portal, you arrive in the portal which is closest to the corresponding nether coordinates

  • if not a new portal is created

• When you travel from nether to overworld, the game checks if there are existing portals in the overworld in a range of 1024 Blocks arround the corresponding portal coordinates

  • If there is one or more portal, you arrive in the portal which is closest to the corresponding overworld coordinates

  • if not, a new portal is created

The BUG-Behavoir in versions up to 1.16.1 was:

Search-Range in Nether: 128
Search-Range in Overworld: 128

• That means the overworld search range is to small, because overworld distances must be NETHER-DISTANCE x 8
  The correct Bugfix would be to increase the overworld search-range to 1024

• Result is, that useles portals are created when you travel from nether to overworld and a matching portal is outside of 128 blocks, but inside 1024 blocks

The BUG-Behavoir in versions 1.16.2 is:

Search-Range in Nether: much smaller than 128
Search-Range in Overworld: 128

• That means now BOTH search distances are to small, and even the portals are not linked correctly when travel from overworld to nether

• Result is,

  • that useles portals are created when you travel from nether to overworld and a matching portal is outside of 128 blocks, but inside 1024 blocks

  • that useles portals are created when you travel from overworld to nether and a matching portal is inside the 128 blocks range

So the it seems that in 1.16.2 they tried to fix the bug, bug they changed the wrong of both values.
And this make this bug even worse, because this would BREAK all long distance portal networks.

@unknown that exactly is the problem, this ticket is changed to "Works as Intended".

But it cant be the final answer, that they yust make changes that break all ways to create and use long range nether portal travel ways.

In 1.16.3 single player when creating the first portal, then coming back from the nether to the overworld an other portal is created.

It seams that the first portal created in the nether was generated in the wrong coordinates corresponding to the overworld. To fix I had to check coordinates and redo the nether portal at the correct spot that was only a 7 blocks away.

If this is supposed to be working as intended is very confusing...

It seems that the support is not considering the new problems since version 1.16.2 / 1.16.3 as part of the same bug, I created a new issue MC-203285 for the new problem.

It is clear that it works NOT as intended The well known and documentated fakt is, that range in overworld should be 1024 and range in nether 128.

Yust look at the wiki:
https://minecraft.gamepedia.com/File:OverworldToNetherPortal.png

Wiki does not define what is intended and what is not, it just describes the current state of the game.

@unknown the wiki is written by players, and it reflects the opinion of the majority of players, how the the game currently should work.
Its true that the wiki is not telling what the intention of the develors is.

But many people playing that game have existing worlds, and they trust in the well know behavior and game updates should not destroy existing features in the game without offering an alternative to keep existing worlds.

Maybe a good middleway to either keep behavoir in existing worlds and to reduce the distance too, would be to make the "portal detection range" changeable in the world config.

So players with existing worlds could keep the portal detection range at 1024 (and 128 in Nether) and other players could have the 1.16.2 behavoir with a range of 128 (and 16 in nether).

Wikis are neutural, they don't have an "opinion", MC wiki only says how the game currently works and points to bug tracker reports if the behavior is believed to be a bug.

I think we go away from the core topic.

The point is, that the reduced detection range will break all existing nether portal networks. And I am quite sure that this can not be the intention behind a bugfix, so the changes from 1.16.2 must be reworked.

Either the range should be changed back to 1024 in overworld and 128 in nether, or there should be a changeable value in the world config, that each server admin can choose if he likes the old range, or the new range that breaks long range nether networks.