Nether portals

[AdmiralTriggerH]

As discussed elsewhere, we need to be careful with the building of Nether portals due the crazy things they can do.
Also we used to have some carefully constructed portals which allowed for fast travel between things, but with the destruction of the old nether they have all gone.
However the real world portals are still there, and some of them were wrecking havoc with the portals in the nether, I kept coming out in other peoples basements etc.
As for simplicity while getting the town hall and togservation deck portals on line, deactivated a number in the spawn village (the ones I came out of instead of the town hall portal.

I then went and moved the town hall portal in the nether to the correct altitude so it should only ever link back to town hall (unless another portal is in close proximity with Town hall.)

I have also built a portal to the togservation deck and to my basement and they are all link with very nice walkways (otherwise you would have to fly as they are in the middle of the air)

WARNING - The section below contains maths that may cause some headaches for those who don't like maths, feel free to skip to below

I have some tips for portal building, remember that the nether is smaller than the real world (well not really but it is for portals) so you need to divide the real world x and z postion of your portal by 8 to get its postion in the nether, ie the Togservation deck is at x=-200 z=57 so in the nether its at x=-25 z=7
(have to round due to minecraft not doing fractions)
However when it comes to height, (altitude, or y) its the same as the real world.
This is where you run into problems ie with my portal (y=6) and the togservation deck, (y=122) they are really close together in the nether, ie about 4 blocks or something in the x and z but when it connects back to the real world it multiples the x and z by 8 and leaves the y and then looks for the closes portal.
Which is uses basic trig (think back to high school maths), thus if my portal in the nether is at say 80 it will connect to the togservation deck because it works out closer, however it its at say 32 (where it is now) it goes to the portal in my basement.

WARNING END- No more maths.

So to keep things simple I suggest keeping most portals at the same heights as it removes the having to do any real maths other than the divide/multiple by 8 which we can all do with the help of a calculator

So I propose that all real world portals within the spawn village be built below y=30 (with exception of those that can't ie togservation deck etc) and all portals in the nether which link to them be built on the same level as mine which is just above the lava.
This will hopefully prevent incorrect linking to portals.

However if you wish to build a one way portal from the real world to the nether than you want it to link to another portal which won't return you to the same portal, if thats the case you need to get the maths right or ask someone to help.

Sorry for the epic post, but I think we need to discuss this before we all go and build heaps of portals

[DaedalusAlpha]

Why would the height (y-axis) be an issue if the algorithm doesn't care about height anyway? It's just a matter of not building portals too close to each other in (x, z) irregardless of y value.

Don't come here and mess up an already perfectly complicated forumla with irrelevant y values

[AdmiralTriggerH]

Well because the y value does matter,
The way it works is when travelling from the nether to the real world it multiples the x and z by 8 and leaves the z as it is, then it looks for the closest portal in a direct line (where the trig comes into play) thus if I built a portal in the nether right next to the togservation decks nether portal that is at the correct x and z to link to the portal in my basement, it would link to the togservation deck in the real world, because it was only about 20 blocks across instead of being 50 odd blocks down.

Thus if we build most of the portals at the same altiude in both the nether and the real world, it means you don't have to bother with y, because its constant.

You have to remember that in the spawn village you have houses that are only 3 blocks apart, so you can get portals that are only 3-6 blocks apart if we don't think about all this, which means the only way to seperate them is in the y dimension.

[DaedalusAlpha]

Are you sure it uses the closest y? In other words; two portals placed on the same x and z but with enough y difference between eachother should be able to link to two different portals with enough y difference between eachother in the nether? If that's the case I have to test it

[DarkDuck]

Y might come into play if you are making portals right beside eachother but I still doubt this.

I know of 2 portals 10 blocks apart but they link to diff portals because there is enough X/Z distance, they Y does not matter.

I think we need clarification on this however I have never needed y before

[Sp!at]

My portals are quite close (5 blocks in the Nether) and the Y axis doesn't have any bearing on them.

[Sorontar]

5 blocks in the Nether is 40 blocks in the real world. I think the issue is more if you have portals above each other in the Nether, what real world portal will they each link to.

Sorontar

[DaedalusAlpha]

I would assume Y comes into play if you have two portals exactly on the same coordinates (x, z), but only as sor says, in choosing which one to connect to, probably always the upper one if the algorithm searches from top to bottom.

I'd think however that under normal circumstances you're a lot more likely to get a mis-alignment with two portals close to each other in (x, z) than exactly on the same (x, z) but in different y. The probability of you happening to put a portal on the same (x, z) as an already existing portal is pretty slim imo.

[AdmiralTriggerH]

I don't think you guys are seeing what I mean.
It will always pick the closest portal in 3D, which means that the y comes into play when you have large differences in alitiude, ie my real world portal at 6 and the togservation deck at 122 because previously the nether portals where mostly built around 80 in the nether, and my portal was only 3 blocks away in the nether (at the same height) (somewhere between 16-24 in the real world). When I left my portal it was looking for a portal at 80 at its coordinates but the portal it should have linked to was at 6, leaving a distance of about 74
However the Togservation deck was about 20 away in the horiztonal plane and about 40 up
and after doing some basic maths (a^2+b^2=c^2) you get a distance of 45.
As you can see the Togersvation deck came out as being closer by about 30 blocks so it always linked there.

Thus by matching the y with both portals as best you can its possible to avoid such things.

[Akira Doe]

Originally Posted by DaedalusAlpha

Why would the height (y-axis) be an issue if the algorithm doesn't care about height anyway? It's just a matter of not building portals too close to each other in (x, z) irregardless of y value.

Don't come here and mess up an already perfectly complicated forumla with irrelevant y values

I don't want to give away my build strat before I start (in Frontier) but I like to build floating islands. If I want it to be truly floating the only way to access it is via nether portals. I usually have one on ground level under the island and one in the exact same x/z on the island above.

From my experience, Y isn't like X/Z, it's the same in the nether as the overworld. So in the Nether, I build a protected ladder from the bottom portal (same Y as overworld) to the one above portal (same Y as floating island portal).

So Y does matter. It also can break portals close together if the distance between portals is shortest on the Y axis rather than X/Z.