On spigot server (for more testing), i created a portal at 1024, 42, 1024, used it and adjusted position in nether to comply to 1:8 rule. Then i created a portal at -2, 42, 1024 (even more then 1024 blocks away), but i came out at my old, adjusted portal in nether instead creating a new one (creating a portal at ~ -200, 42, 1024 worked).
Vanilla server:
Portal 1a (overworld-old): 420,45, 1797(...1800)
Portal 1b (nether-old): 51, 45, 222 (...225)
Portal 2a (overworld-new): -618, 55, 1600 (...1603)
Portal 2b (nether-new) expected generation at: -77, 55, 200
X of Portal 2a once were at -610 but since it didn't work (even though more than 1024 blocks away), i recalculated related to x of Portal 1b, which was < 128 blocks, so i increased x to -618. Now distances of 1024 and 128 are given, but Portal 2b isn't generated, instead im coming out of Portal 1b.
I cannot tell why this is happening. I don't know which distance is more relevant, overworlds 1024 or nethers 128 radius?
As i understand, Minecraft is searching 128 blocks area in nether for active portals.
Is this 128 blockradius (respectively 1024 for overworld distance calculations) "increasing", when Portal 2b would generate somewhere beside the calculated spot (because of lava, other blocks), but then being closer than 128 blocks and then finding Portal 1b, which situation would prevent a new portal generation?
Is the game searching an active Portal around the calculated spot or around the closest possible spot (where a portal can be generated in nether)?
When i build Portal 2b manually, traveling works as expected.
Comments 7
The 1024 are coming from the german translated wiki, since i also checked the english site, i tested with 128 in nether as well.
By reading more about this in the english wiki, i understand, that it normally should search a portal first, if not found THEN check surrounding (16 blocks radius) for possible creation and do so, but it seams that those steps are changed/mixed.
I'm not sure I understand your report. However, I think this is working as intended: Nether portals in the nether can be offset up to 128 blocks from the calculated position, which is 1024 blocks in the overworld. Two nether portals built in the overworld, 2048 blocks away from each other, can come out at the same nether portal in the nether if the portal in the nether is just in the middle between the two calculated positions.
They can, if you contruct it this way, but it wasn't constructed with a portal in between. Maybe you concentrate on the coordinates i have provided.
Portal 1a (overworld-old): 420,45, 1797(...1800)
Portal 1b (nether-old): 51, 45, 222 (...225)
Portal 2a (overworld-new): -618, 55, 1600 (...1603)
Portal 2b (nether-new) expected generation at: -77, 55, 200
Portal 2b didn't generate which should.
Portal 2a coordinates, in nether scale: (-77, 200)
Portal 1b coordinates in the nether: (51, 222)
The z coordinate is clearly less than 128 blocks larger than that of portal 1b, the x coordinate is exactly 128 blocks smaller than that of portal 1b. Thus, portal 2a links to portal 1b.
Resolving as WAI, see this page for more info: http://minecraft.gamepedia.com/Nether_portal
I'm not sure where your 1024 figure is coming from. The search radius in both dimensions is 128, strictly in the horizontal plane (x and z only).