Nether Portals Basics

Installation -> Basics -> Command Reference

Summary

Create Nether portals like you would in single-player.
Nether portals in world X look for a world called X_nether, and take you there if it exists.
Nether portals in world X_nether look for a world called X, and take you there if it exists.
Redirect Nether portals by "linking" two worlds: /mvnp link {end|nether} X Y.

What you need

Before you begin to use Nether portals, you'll need...

To install Multiverse-NetherPortals.

Getting started

Note: you may skip this section if you know how to create a standard, single-player-style nether portal.

Once both the Core and NetherPortals plugins are installed on your server:

Log in to your server.
Gather up at least 10 obsidian, as well as a flint and steel.
Create a portal in the usual (single-player style) shape. It should have an internal size of 2 x 3 blocks and a total external size of 4 x 5 blocks.
Light one of the inside surfaces on fire with the flint and steel.

You should see the inside of your obsidian frame light up with purple portal tiles. Congratulations - you made a nether portal!

Behavior

By default, Nether portals behave similarly to how they do in single-player: they take you to a Nether world. However, with Multiverse 2.0, there are some added features you can use to make your Nether portals even better; moreover, Multiverse 2.0 makes one Nether per world a reality, instead of having one Nether overall.

Standard

When you have multiple worlds, what does it mean to go "to the nether"? With Multiverse, the nether gets interpreted following a few simple rules:

Each world gets its own nether by default.
For a world named X, the Nether world is named X_nether.
If a Nether exists for a world (e.g. X_nether is already a world), the portal takes you there. Otherwise, nether portals do nothing in that world - the plugin will not create a nether world for you. (The converse is also true, for players already in the Nether.)

Without any customization, that's it. Each world gets a separate Nether, and those worlds behave just like any other Multiverse world - the only difference is that they have _nether at the end of their names. (Bold users can even change the suffix in the Multiverse-NetherPortals configuration file.)

Customizing ("linking")

Inevitably, there are users who want to use Nether-style portals to teleport to other regular worlds. With Multiverse-NetherPortals, this is easy! Just link the two worlds together.

"Linking" worlds involves setting the destination of nether portals in one world (call it X) to another specific, usually non-nether, world (call it Y). To link all the Nether portals in X to world Y, run:

/mvnp link {end|nether} X Y

Now, when your players step into a Nether or End portal (depending on what was specified in command) in world X, they'll be taken to world Y instead of world X_nether or X_the_end. What's more: all the normal Nether options still apply, including portal auto-creation (if specified) and distance scaling.

Keep in mind that links are not two-way. You can link X to Y, but if Y isn't linked back to X, nether portals in Y will take you to Y_nether, not X.

Of course, what good would world linking be without world unlinking? You can remove the link between X and Y by running:

/mvnp unlink {end|nether} X

After that command, Nether or End portals in world X will once again lead to world X_nether or X_the_end.

Linking and unlinking works in both normal and nether worlds - you can leave world X pointing to X_nether, then link X_nether to world Y. More complicated configurations like this can literally let your users walk "through hell and into another world."

Another thing to note is that linking a given portal type in a world to itself will disable any of those portals in that world.

World scaling

By default, the standard single-player Minecraft Nether uses something called "distance scaling" - for every chunk you walk in the Nether, it's equivalent to eight chunks in your regular world. A similar effect is - naturally - possible using Multiverse. But first, we need to take a brief diversion into how the scaling works.

A little math

To begin, every world has a "scaling" associated with it. This scaling can be any positive number: 1, 2, 100, and 0.42 are all valid scaling values. Using these values, we then say that the "scaling factor" from world X to world Y is:

SF(X,Y) = scaling(X) / scaling(Y)

So if world X has scaling 6 and world Y has scaling 2, then the scaling factor from X to Y is 3.

What does it all mean?

We've tossed around a bunch of numbers here, but what exactly is a scaling factor? This definition is very important in world scaling, so remember it well:

The scaling factor from X to Y is how far in Y you can go by walking in X.

For the more mathematically inclined, this can also be expressed as:

dist(Y) = SF(X,Y) * dist(X) = (scaling(X) / scaling(Y)) * dist(X)

Let's consider an example. Once again, we have our two worlds X and Y. Say that X has scaling 2 and Y has scaling 1; then the scaling factor from X to Y is 2. Now our friendly player Alice walks 100 blocks in world X; that's the same as walking 200 blocks in world Y. Player Bob, on the other hand, isn't so smart: he walks 100 blocks in world Y, then moves to world X and finds out he's only gone 50 blocks.