Is Minecraft Chunk Blending Safe?

As it wasn’t available yet in any form. For those unaware, your entire Minecraft world is made up of 16 block long and wide “chunks”, all stitched together when loading a world. If you’ve ever somebody reference a “chunk error”, an event caused by one of these chunks

Failing to save or load properly, now you know where the name comes from. Since 1.18 has now been released, I think the main concern that just about every single player is going to have is whether or not this new blending feature is going to completely destroy their

World. Okay maybe that’s a bit extreme, but I think you get the idea. Long story short, blending prevents this crap from ever happening again. Any new chunks that you generate in 1.18 that border pre-existing chunks will be blended together. But, does it work? How

Does it work? Is it safe? Are there limits? Can we break those limits? Now we’re asking the right questions. So let’s go ahead and check it out. So let’s start with the basics. You have a world that you want to load in 1.18, and you

Want to make sure it’s safe. Right off the bat, I’m gonna tell you that it’s a good idea to back up worlds that you care about. If Figonometry, the first person to ever walk to Beta 1.7’s “Corner Far Lands” can keep their 131 gigabyte world backed up, you can

Back up yours too. So now, let’s set the stage. This is my first ever Minecraft map that I call, “The Peaceful Map”. It’s over 11 years old, and was started way back in Alpha 1.2. While I’ve not updated the content of this map since November of 2013, around the time

1.7 was released, I actually did a pretty difficult upgrade to the map in June of this year while dealing with really aggressive chunk-loading problems in versions beyond 1.12. This map means a lot to me, and I wanted to ensure those who came across it in modern

Times could enjoy it to the fullest. For the first demonstration, I’ve used a program called Amulet to prune everything beyond a 10 by 30 chunk area surrounding the spawn point, so we know exactly where the chunk borders will be. I’ve also changed the biomes within

Those chunks to be either be a forest biome or an ocean biome, as it used to be one massive plains biome. With the world ready for 1.18, let’s go ahead, and let’s fire it up. Upon loading up the world, a few things are immediately obvious, one of which is that

Nothing has gone catastrophically wrong. If anything, I am seriously impressed as to how well this has worked. So, how does it work? What behavior should you look out for? Well, first off, Minecraft 1.18’s blending will not change any blocks within pre-existing

Chunks at all. All of the blending happens within new 1.18 chunks only, which prevents naturally generated structures on the edge of your old world from blending with the new terrain. For the sake of demonstration, I intentionally created this scenario behind

My mountain house’s entrance. As you can see, the blending, just, works. It doesn’t attempt to blend straight up the wall or anything weird like that. The only place where things went sort of wrong is at my minecart bridge, where the blocks underneath it meet up with

The new terrain. But even that isn’t a major problem. As we continue to look around, we can very clearly see where the old and new terrain meet within the ocean biome, but that’s only because worlds generated before Beta 1.8 have no under-water block variety, and

Their sea level is set one block higher than all versions after Beta 1.8, meaning it’s another problem you’re not likely to deal with. The only place you are likely to notice a significant difference is when terrain of extremely differing heights are forced to

Blend together, in which case the blending will look a little overly smooth. Now hang on a minute. While flying around some more, I found a straight line of sand where the old terrain meets the new terrain. What gives? Is this a bug? Is this something

You’ll have to deal with? Again, no. 1.18’s chunk blending pays attention to what biomes exist next to the terrain that it will be blending with. This instance of my Peaceful Map was all forest and ocean before blending, so let’s run an experiment outside of the

Peaceful Map. To see how this will actually look in practice, let’s generate a normal world in 1.17, move around a bit so the world isn’t a perfect square of chunks, close the world, swap out the level data file with that of a 1.17 single-biome ice spikes world, and

Then load it up in 1.18. So long as you don’t load the world a second time in 1.17, Minecraft 1.18 will blend the normal terrain with a new ice spikes biome, because as far as Minecraft 1.18 is concerned, it’s blending what it thinks is a 1.17 single-biome ice-spikes world. As

You can see now, there are no solid lines of blocks anywhere. If this were just a normal 1.17 world loaded in 1.18 without the level data file changes, it might be difficult to tell that anything happened at all, and that’s, kind of the point.

One last note I’ll make above ground is that structures that were queued to spawn within 1.17, but that appear within 1.18 terrain seem to follow the shape of what the terrain would have been in 1.17, resulting in this absolutely hilarious floating village that

Occurred with the world that just generated. Above ground is not the only point of contention with chunk blending however, so let’s go underground, where things get… messy, but reasonably so. As I mentioned before, blending will not mess with pre-existing chunks. If a new cave

Does coincidentally meet up with an old cave, and / or if the old cave is big enough, some blending does appear to occur within new chunks, but it isn’t much. Using Amulet again, we can see where the 1.17 cave systems for this world end, and what that looks like in-game

In 1.18. The cave systems do not line up at all. Plain and simple. That really does explain everything that’s going on above bedrock underground, so let’s go below bedrock. All bedrock blocks that used to exist between a y level of 0 and 4 have been replaced with deepslate now.

Because the bottom bedrock layer was always supposed to be solid, nothing will ultimately connect through this barrier within your old world chunks. But seeing as absolutely everything below 0 is brand new, on both new and old chunks, everything below 0 generates like

You would expect for 1.18, with no chunk blending artifacts impacting this area at all. If you do upgrade your world, but you don’t want to venture too far, consider adventuring downwards. If you watch my videos a lot, then you know what’s coming next. I’m going to try and break

Chunk blending. Key word, try. If you’ve enjoyed the video up to this point, please consider subscribing if you haven’t already. As you’ve seen throughout this video, chunk blending works really quite well, but there are some things we can do. First off, you know how

I’ve been swapping level data files around throughout this video? Well, if we take this instance of the Peaceful Map, but slap in the level data file for a floating island ice spikes world, we get, this. This, is awesome! The Peaceful Map almost looks like a hidden

Valley amongst the floating ice spikes chaos. The actual terrain blending along the old chunk border is a little bit rough with this broken setting, even with the seed being the same, but I can tell you from experience that this result is inconsistent, and heavily world

Dependent. I could probably do this all day long with a variety of different level data settings, so let’s get crazy. Using the same program as before, I’m gonna delete a checkerboard pattern of chunks, and change the level data file to that of a 1.17 caves crimson forest

Preset. Upon loading up the world, ehhhh… what?! Yeah… the caves preset no longer works properly in 1.18, nor is an even option when creating a new world in 1.18 anymore. Even though the crimson forest blocks aren’t here, the actual blending works pretty well,

All things considered. For now, let’s try two more items that I think you’re gonna want to see. First, taking a 1.17 superflat world and blending it with a normal 1.18 world. This works far better than I expected it to, and it provides us with a nice perspective

Of how the whole process works. Even when blending is forced to work under such extreme circumstances, for the most part, it just does. So last up, and one I really think you’re all gonna want to see is, the Far Lands.

Using an old Minecraft 1.15 mod that I’ve shown off before, I’ve forced the Far Lands back into existence, and forced them to generate only 47 blocks from spawn. After doing so, I loaded this world into 1.18, flew to where the far lands chunks would end, anddddd…

Wow. This is everything that I expected it to be. And while I might be out of time for today’s video, this really does show just how many possibilities there are for tinkering around with Minecraft 1.18’s new chunk blending feature. Are you gonna update your worlds

To 1.18? Are you gonna try anything that you saw today? Let me know in the comments below, and thanks for watching!