I got a overworld portal at my base at -3080/10/-1672 connecting to a netherportal at -385/9/-209
Works like a charm.
Now I'm working on a netherroof portal wich I build at -400/130/-208 wich links up to an overworld portal at -3200/10/1664, wich is pretty close to my other overworld portal for easy access. I've checked my math and in some ways the portals works.
My main overworld portal to my main nether portal works both ways
Netherroof portal links to newly made overworld portal, works.
Newly made overworld portal links to main netherportal instead of netherroof. DOESN'T WORK.
So from the nether side to overworld works, the other way around both connects to main nether portal.
Only Y dimensions differ obviously. Any idea why this doesnt work?
A nether portal that sits in or on the netherroof bedrock such that the lowest purple swirly portal blocks are at y=128 or higher cannot be connected to from an overworld portal. Drop the frame by 1 block so that the purple swirlies start at y=127.
All of my netherside portals (now up to 17) have bases at level 119. This gives me headroom to get the portal in without running into the bedrock roof. Although this requires tunnels to be cut connecting them that's easy as is bridging over the few small voids that get up that high. Also avoids having to crack out the bedrock .
I currently have a netherside network of size over 2,5k in both X and Z but all at Y = 119.
highest bedrock block is at 127. I've lowered my portal to the bedrock level, so the lowest obsidian is at Y128 now, but still the overworld portal connects to the old nether portal. Is it really the Y level that makes this difference, eventhough the portals are linked up perfectly X and Z?
Ah too bad, I saw some youtube videos about netherroof portals that work both ways, but it seems that as soon as you add a second portal, for nether access for example, it doesnt work anymore.Hopefully they'll expand upon this feature or approved bug as some call it.
The problem is that the distance from your rooftop Nether portal is almost exactly the same to both of your Overworld portals, close enough that it's impossible for me to figure out which is closest without knowing exactly which blocks you are giving the coordinates for, also each portal is at least 2 blocks wide so it may well make a difference which side (left/right not front/back) you go through.
Basically your first Overworld portal is about 120 blocks away in the X direction from where the second Nether portal is trying to connect while the second Overworld portal is about 120 blocks lower than the connection attempt.
I'd try moving the second Nether portal to, say, -410/130/-208 or -400/130/-200 (I wouldn't think it would take more than that due to the 8 times X and Z multiplier but if that isn't enough try a bit further but not more than 15 blocks in either direction or it won't connect to either Overworld portal and will create a new one. ) that will make the Overworld portal less exactly matched to the Nether one but that wouldn't matter much as long as it's the closest.
Seems I was a bit confused, it's the distances from the Overworld connection attempt to the 2 Nether portals, so you don't want to move the second Nether portal further from it's Overworld portal.
But moving the first Nether portal further from the second Overworld portal may well do the trick, even if that makes it a little bit further from its Overworld portal (unless that makes that connection fail.)
It's confusing, you may have to move one or both of the Overworld portals as well.
Thanks, I'll try these suggestions later tonight! I'll let you know what happens
EDIT: went in creative to test things. discovered that if the portals are around 240 blocks away from eachother in the overworld, 30 blocks in the nether on the Z axis, both connections work. haven't tested on X axis, but I assume it will work too. both overworld portal Y axis were around the same height, same as both netherside portals.
Sorry for being so muddleheaded and looking at this backwards.
I think I've got it now.
(Though I'm not sure I'd trust myself at this point.)
Since the 2 Nether portals are 120 blocks apart height wise and only about 15 blocks apart horizontally the difference has to be made up horizontally if you want your 2 Overworld portals to stay at the same level.
Since horizontal distances are multiplied by 8 when going from the Nether to the Overworld that means the Overworld portals would have to be about 960 blocks apart.
My suggestion would be to set up some kind of elevator system, bubble columns and or a drop shaft perhaps, and move the second Overworld portal more than halfway up to the level of the Nether portal it should connect to.
I've tested (in 15.2 though) and got -410/130/-207 to connect both ways with -3200/72/-1665 while -385/10/-209 was connected to -3080/10/-1672.
The -410 instead of -400 wasn't on purpose, that was left over from my previous attempts.
If you are going to be messing around with elevators anyway it might be more convenient to put the second set of portals straight above the first pair, then you'd only have 15 blocks to walk instead of 120.
Unless you have something at -3200/Y/-1664 of course.