Minecraft – Does length dilation affect the Y axis in the Nether

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It's known that traveling one block in the Nether is equivalent to traveling 8 blocks in the real world, and I can confirm that along the X and Z axes by building four portals: two in the Nether and two in the real world.

But I can't seem to corroborate the length dilation from the Nether to the real world along the Y axis (height).

That is, if I build the following portals:

Nether:
- Portal 1 at n height
- Portal 2 at n – 8 height
Real world:
- Portal 3 at m height
- Portal 4 at m – 64 height

I expect Portal 1 and 3 to link up while portal 2 and 4 should link up. But in my testing, if I use portal 1 or 2, they lead to portal 3, and if I use portal 3 or 4, they lead to portal 2.

Is there any evidence—in the form of a video, a world save file, or notch—that one nether block equals 8 real world blocks along the Y axis? I'm trying to determine if my error is in calculation or if it's in execution.

    Y     
    │      
    │      XYZ reference system
    └───X  for this question.
   ╱
  ╱ 
 Z

Best Answer

According to this thread in the Minecraft Forums that seems to have peeked into the code, length dilation does not affect the y-axis.

http://www.minecraftforum.net/topic/345806-nether-portal-science/

Summary version

Calculate coordinate of destination based on entry coordinate. (X, Y, Z) <---> (X*8, Y, Z*8)

At destination, look for the closest active nether portal within a 128 block radius of the player (257x257x128 area centered on destination) (the Euclidean distance (the 3D distance)). Teleport player there if one exists.

If no portal exists in the 128 block radius, the game creates one by looking for the closest possible nearby position within a 16 radius column (33x33x128 area) that has enough space to spawn a portal. And teleports the player there.

And if there's no possible spawn position with solid ground, it just creates a portal at the destination anyway, converting any blocks in the way into a portal.

Related Solutions

Minecraft – Why won’t the portals link up properly

As you said it yourself, portals do take the vertical distance into account. This means you cannot make a sky portal higher than y~=192 if your ground portal is at sea level, as distance from Nether ceiling (your top portal) to sky portal must be less than from Neither ceiling to level of your ground entrance portal.

  Overworld|Nether

Sky    [@]                          192
           ^
          A|
           v
             [@] Nether top         128
             [@] Nether bottom
           ^
          B|
           v
Ground [@]                           64

But there is a solution!

By moving your ground entrance away horizontally, you can increase distances just enough to fix all the portals (after moving Nether portals to the ceiling, of course).

I have written this handy spreadsheet to easily calculate all distances for two pairs of portals (coordinates in frames are editable). By just moving ground portal from x=-3653 to x=-3623, thirty meters away, you can fix everything! Well, maybe a couple meters more to be sure :-) Again, note I've assumed your Nether portals to be at y=110 and 120, otherwise your Ground portal would have to be much farther.

Minecraft – Nether Spawns: Y Axis Relevant

While converting between Overworld and Nether coordinates, only X and Z are scaled by 8, y remains the same (in your calculation y is also divided by 8). This is not the problem, actually.

Here is how it works: When you enter a portal, the game calculates the ideal point where you should appear on the other side (by scaling X and Z with 8). Then it searches the closest portal to that ideal point.

If you do the calculations backwards (Nether -> Overworld coordinates), you get that entering nMain will try to go to here in the Overworld (let's call it nMainOut):

x: -16
y: 60
z: 248

...and 'nTower' will go to here (let's call it nTowerOut):

x: 16
y: 67
z: 288

The game searches the closest portal to those 'out' points. For both of these 'out' points the closest portal happens to be the Main portal at:

x: -22
y: 65
z: 261

The distance between points is euclidean distance, that is

distance = sqrt( (x1-x0)^2 + (y1-y0)^2 + (z1-z0)^2 )

If we calculate the distance between nTowerOut and Main we get 55.1

If we calculate the distance between nTowerOut and Tower we get 177.2

That is why nTower goes to Main.

With your current setup, I'm afraid it is not possible to build a Nether portal that goes to your Tower portal, unless you move the Main portal down near bedrock and also move nTower near the top of the Nether.

Best Answer

Related Solutions

Minecraft – Why won’t the portals link up properly

Minecraft – Nether Spawns: Y Axis Relevant

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