I believe the two portals in the overworld have to be under 128 blocks apart total and also should be at least 8 blocks apart horizontally. I just used some simple 3D coodinate math and built the one in the nether at the midpoint.
Are you saying if you travel into the nether side portal on the blue or red level platforms you arrive at a different overworld portal?
yeah, that’s exactly it.
I personally like doing a much less impressive, but maybe more useful trick, putting one portal at the very base of a tower, and putting another at the top, while arranging the nether side to only connect to the top. you go in the bottom, go straight back through the nether side, emerge at the top.
Yeah I knew the other way worked but I had no idea you could link 2 to 1 and back again, gonna have to play around with this now with a bigger portal and see if you can link to 3 maybe… I always assume it just took the lower corner of the portal as the linking coord but it must use your actually position
I got the idea from someone on YouTube making a secret base where if you crouched and stood on the edge of a portal in the nether it would link to a different portal than if you were just standing in the center.
I like those 2-in-1 portals - building them involves a lot of small tidbits of maths, to ensure that they work well, but they’re a great way to access floating bases without ruining their looks.
Do you mind if I drop a mini-tutorial here on how to do it?
You need to keep track of the following coordinates:
- overworld portal “A” - let’s say that it is at (ax, ay, az)
- overworld portal “B” - let’s say that it is at (bx, by, bz)
- the block “N” of the Nether portal being used to access “A” - let’s say (nx, ny, nz).
- the block “M” of the Nether portal being used to access “B” - let’s say (mx, my, mz).
In OP’s image, the block “N” would be the block of the Nether portal immediately above the red concrete blocks; it’s where your feet would be, once you hop into the portal. While “M” is the one immediately above the blue concrete.
Your Nether portal will link to both A and B if:
- (8nx-ax)² + (ny-ay)² + (8nz-az)² < (8nx-bx)² + (ny-by)² + (8nz-bz)²
- (8mx-bx)² + (my-by)² + (8mz-bz)² < (8mx-ax)² + (my-ay)² + (8mz-az)²
This might look complicated, but it boils down to “N is closer to A than to B; M is closer to B than to A”.
Notice the 8’s in both equations. They’re important there because 1m in the Nether = 8m in the Overworld, but only in the X and Z axes. Don’t add those 8’s to the Y coordinates!
If you want to be a bit lazy, make sure that both overworld portals share one or two coordinates. For example, if portal A is at (10, 200, -10) and portal B is at (20, 70, -10), then their Z coordinate is the same, and you can simplify the inequations to remove any term with “z” in it. And if the portals were exactly one above another, the inequations collapse to
- (ny-ay)² < (ny-by)²
- (my-by)² < (my-ay)²
Or if they’re on the same X and Y coordinates, and only Z is different:
- (8nz-az)² < (8nz-bz)²
- (8mz-bz)² < (8mz-az)²
(If anyone wants, I can help out with the maths for a practical situation.)
Interesting, my method was to use ((ax+bx)/2)/8 , (ay+by)/2 , ((az+bz)/2)/8 to find the coordinates for the portal in the nether. Then just a little trial and error to calibrate it correctly. However, your method seems a lot more robust and would be a lot easier to troubleshoot.
Your method is simpler, and it works great. The problem appears when you’re a bit more specific on where to put the portal in the Nether. For example, in my current world:
- Portal A had to go at y=200, in the free corner of my floating island
- Portal B had to go at y=(65~80), on the ground (there’s a big slope there)
- the Nether portal had to go at y=120, due to my Nether hub, and I wasn’t willing to break the bedrock ceiling
Averaging A and B would force me to put the Nether portal around y=(132~140), outside my hub and over the roof. So I had to calculate the coords for B instead, to push it far enough in the X and Z axes to compensate the Y distance. Those inequations did the trick.
That happened to me once!
