Custom Worlds in Minecraft 1.12 and Below

I genuinely haven’t played Minecraft in quite a long time, so when aabicus asked me about a Minecraft world I’d made a video and an article on, I loaded up Minecraft, got the latest update (1.13) and… realised that custom worlds weren’t a thing any more.

There were some custom presets that you can use in Minecraft 1.13, alongside some minor alterations. But Minecraft 1.12 (and I think a couple of versions before) have the ability to alter very… delicate parts of the terrain generation process.

Minecraft Custom Generated Worlds
A custom world created with random values.

You get four pages of things to fill out. The very first page is quite basic. You select whether you want things like dungeons and villages to spawn, you can set the main water level and you can select things like Biome Size and River Size. You can also set your world to only ever have one biome (which I did once in a Mooshroom Biome challenge). What’s most unusual is that you can set the rarity of water oceans and lava oceans. I wouldn’t recommend lava oceans, they end up being nothing more than impassable terrain that you can do very little about.

The second page is also quite basic. It basically sets the chances of various blocks spawning. This applies to what’s under the surface, not what’s on top, so you can’t set dirt to not spawn at all. But you can do crazy things like making Diamonds and Gold insanely common, spawning in 20-block chunks and being capable of spawning all the way at max height. Or you can make everything apart from gravel and the not-stone stone blocks be really rare and give yourself a really hard time.

Minecraft Custom Generated Worlds
Randomly selected values

The third and fourth page are basically the same. The only difference is that the fourth page lets you enter specific numbers, while the third page utilizes sliders. These two pages let you modify the values that Minecraft uses to generate its terrain.

Now, the reason the Custom World creator doesn’t exist in Minecraft 1.13 is because Minecraft 1.13 actually changes how the world generates. Like, the algorithms themselves have changed, so these values simply won’t work in Minecraft 1.13. This also means that you can’t copy a Minecraft 1.12 or older world into Minecraft 1.13 without having strange goings on in the world generation. Even if you use the same values and the same seed, the fact that there are different biomes and that oceans are completely different causes Minecraft to create obvious differences in terrain.

It’s not something to be scared of. It happens every time Minecraft adds new terrain generation or new biomes. It just means that you really shouldn’t try and play a Minecraft 1.12 world in Minecraft 1.13 without at the very least creating multiple backups first. Especially if it’s a well-played world.

Plus, custom worlds are said to come back at some point. Just not yet.

Anyway, back to the custom world creator.


The thing is, you can create some really, really interesting worlds. It’s also very easy to create unplayable worlds as well. If you just hit that random button a few times, you might luck out with something cool, but often you end up with massive square spires. In fact, maxing everything out gives you nothing but towers that scrape the top of the world, surrounded by falls into water. A world with max settings is almost unplayable since no trees can spawn outside of Ocean biomes (weirdly enough) and enemy mobs are everywhere, even in daylight. I mean, you MIGHT be able to survive if you set the world to creative and get a good spawn, but it’s unlikely.

Minecraft Custom Generated Worlds
The only livable places are ocean biomes, which aren’t scraping the maximum build height and occasionally have trees.

Minecraft Custom Generated Worlds

But a world with everything set to its lowest settings genuinely IS unplayable because you spawn at bedrock, underwater. Unless you have creative mode on, you’ll never make it to the surface. Should you get insanely lucky though, you could eek out a living on a floating village, but that’s about it.

Minecraft Custom Generated Worlds
This was the only thing nearby, apart from some fossil structures that generated because we were in a desert biome.

As for other randomly generated worlds? Many of them will be very difficult, with high hills and mobs everywhere, as well as few trees. But sometimes you get oddly surfaced worlds, either incredibly large and thin pillars or perhaps even floating islands. If you’re looking for a cool world to play Survival Mode in though, you really should test the world in Creative Mode first, because you’ll often spawn somewhere surrounded by mobs even though it’s daytime. Weirdly, the most ‘playable’ areas in these worlds tend to be Oceans and Deep Oceans, if you create a high enough world.

The trick is to adjust the settings gradually. You can recreate any Minecraft world with ease, so you can just recreate a world you like and alter one or two settings up and down and see what happens.

Here’s just a handful of worlds you could create.

Just so you know, the seed used in all the maxed/minimum settings worlds is SPUF, and the randomly generated ones use the seed Medic, in case you want to try them yourself.

As for the weird colours? That’s just my weird random grass/tree colour texture pack.


Phovos writes 50% of all the articles on the Daily SPUF since she doesn't have anything better to do. A dedicated Medic main in Team Fortress 2 and an avid speedster in Warframe, Phovos has the unique skill of writing 500 words about very little in a very short space of time.

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