Ocean generation in existing world for 1.21?

[kunchboy]

I started my world with default exploration settings for landcover etc. so don't get any oceans. When 1.21 releases and I update, will that remain the same?

I have previously made a copy of my world and manually entered commands to change the worldgen so oceans generate further out, but it causes generation errors where the old and new terrain generates. Does the chunk smoothing in 1.21 fix that? I would like oceans in my game but don't want the glitchy terrain.

Thanks

[Zane Mordien]

If its terrain is already generated in your world then you are pretty much stuck with it. The smoothing would only happen when new terrain is generated in your world after 1.21 is released. You can try to refresh those areas afterwards with wgen commands but it will nuke everything in the chunks. 

[kunchboy]

On 7/27/2025 at 11:38 PM, Zane Mordien said:

If its terrain is already generated in your world then you are pretty much stuck with it. The smoothing would only happen when new terrain is generated in your world after 1.21 is released. You can try to refresh those areas afterwards with wgen commands but it will nuke everything in the chunks. 

Yeah I'm wondering about if I explore new chunks with my current settings if it'll generate patches of ocean. Or if I change my world settings with commands, and explore new chunks, if there will be glitched terrain where the old chunks meet the new ones. (The patch notes mentioned chunk smoothing?)

I'll probably end up just experimenting with backup worlds when it releases and report back for anyone else that might be wondering.

[Thorfinn]

4 hours ago, kunchboy said:

The patch notes mentioned chunk smoothing?

From what I'm seeing, it just means that the terrain is more traversable. It doesn't look like the landforms themselves have changed much, but the Perlin noise filling the landform seems smoother. I have not verified it by looking at the numbers, and don't intend to, at least for a while. That's my impression, though. Which means that, yeah, transitions between old and new generation are probably going to look a little skanky. Like if you set the location for the RA in the middle of plains, and regened enough of a radius to make it so.

[kunchboy]

To anyone who comes across this and is wondering the same thing, I did some experimenting. I went onto my main world generated pre-1.21 and changed the landcover to 0.7 (previously 1). Ocean cover was set to 1, I didn't change that. Loading new chunks after changing gave mild terrain weirdness but no jagged chunk cutoffs like 1.20 if changing the landcover. So you are able to have oceans in previous worlds if you load new chunks after changing the settings with commands, and the chunks won't have odd cutoffs

EDIT
While exploring more, I DID come across some large chunk errors where the terrain will just cut off and not smoothly merge with old terrain. However, the above still stands. Most terrain seems to smooth and seems to do so more than 1.20.

Personally, I'm just going to make it part of my worlds lore. Strange things happen when you mess with timelines and time anyway. It almost makes sense to canon, lol.

Edited September 3, 2025 by kunchboy

[noarsy]

On 8/31/2025 at 1:43 AM, kunchboy said:

To anyone who comes across this and is wondering the same thing, I did some experimenting. I went onto my main world generated pre-1.21 and changed the landcover to 0.7 (previously 1). Ocean cover was set to 1, I didn't change that. Loading new chunks after changing gave mild terrain weirdness but no jagged chunk cutoffs like 1.20 if changing the landcover. So you are able to have oceans in previous worlds if you load new chunks after changing the settings with commands, and the chunks won't have odd cutoffs

EDIT
While exploring more, I DID come across some large chunk errors where the terrain will just cut off and not smoothly merge with old terrain. However, the above still stands. Most terrain seems to smooth and seems to do so more than 1.20.

Personally, I'm just going to make it part of my worlds lore. Strange things happen when you mess with timelines and time anyway. It almost makes sense to canon, lol.

how'd you go about doing this? i made my server in 1.20 with default gen settings so no oceans. will i have to change the gen settings and then do the commands to regen?

[kunchboy]

14 minutes ago, noarsy said:

how'd you go about doing this? i made my server in 1.20 with default gen settings so no oceans. will i have to change the gen settings and then do the commands to regen?

Hi, I just used commands to change the worldgen settings from in-game. Make sure to backup your world before upgrading or messing with commands, especially worldgen commands.

The command I used was /worldconfig landcover 0.7 
After you use the command you'll have to save and rejoin, and then any new chunks you explore will generate with the new setting from the command. I used the wiki page on world config here to help. There's lots you can mess with, but it might get glitchy, so remember to make backups if you muck with it :)

[Echo Weaver]

I have a world that originated in 1.19 that I'd like to continue playing in 1.21, and I'm still confused about what settings I would need to change for freshly-generated chunks to contain oceans. I spent an absurdly long time looking for the treasure hunter and am finally prospecting for tin to produce a tin bronze pickaxe. I'm just about to enter the Steel Age but was only ever able to produce bismuth bronze. Every story-related step in this world has been slow, but I don't mind because I've been enjoying the process. At any rate, this is just to say that I have some translocators and a decent amount of exploration around a central base a few chunks from initial spawn, but I have not been pressed into the much longer journeys promised by the story. There's a lot of opportunity for oceans.

That's only tangentially relevant. What I really want to understand are what the landcover settings do and what needs to be changed after converting to 1.21 to allow whatever the default oceans would be on a new game. I accept a few chunk seams. I just still don't understand how ocean generation works.

[DrCopper]

2 hours ago, Echo Weaver said:

That's only tangentially relevant. What I really want to understand are what the landcover settings do and what needs to be changed after converting to 1.21 to allow whatever the default oceans would be on a new game. I accept a few chunk seams. I just still don't understand how ocean generation works.

I recently attempted to solve essentially the same question, and, while I wouldn't try to explain exactly what each setting does, these are the commands that I used:

/worldconfig landcover 0.975

/worldconfig oceanscale 5

And now my save file says "No custom configurations" when I mouse over the world name, which I assume means I "corrected" the settings to match the default for new games now.

Haven't gone exploring too far yet to see how bad the chunk seams will turn out though. 

EDIT: Typed all this up and got the actual commands wrong. Fixed now...

Edited September 9, 2025 by DrCopper

[Echo Weaver]

While looking through the worldconfig commands on the wiki, I found this:

Quote

/worldconfigcreate string potatoeMode [true|false]
Whether or not the game generates moss on trees.

That looks like some kind of inside joke....

Also, part of the issue is that the wiki, which I know is fan-written, doesn't have the more recent worldconfig commands. 

Edited September 9, 2025 by Echo Weaver

[Thorfinn]

Also check out the prune command. You may find that you want to regenerate large sections of your already explored map that you have not built on. Make a backup first, obviously, but I had very good luck with it. Got a nice ocean not too far away from base camp. Used to be plains, I think.

[EDIT]

Oh, and remember that you can use .chb in-game to get the most up to date info on commands, both client and server. Command HandBook, I'm guessing.

Edited September 9, 2025 by Thorfinn

[Echo Weaver]

38 minutes ago, Thorfinn said:

Also check out the prune command. You may find that you want to regenerate large sections of your already explored map that you have not built on. Make a backup first, obviously, but I had very good luck with it. Got a nice ocean not too far away from base camp. Used to be plains, I think.

[EDIT]

Oh, and remember that you can use .chb in-game to get the most up to date info on commands, both client and server. Command HandBook, I'm guessing.

I don't totally follow -- what's the prune command?

I didn't know about .chb and had forgotten about the Command Handbook. Thanks.

ETA: Hmm. It doesn't look like there are any worldconfig commands in the command handbook?

Edited September 9, 2025 by Echo Weaver

[Thorfinn]

Prune deletes any blocks that have fewer than a specified number of changes to them. /prune, but I don't recall the parameters. Like most stuff, it's too easy to look up when I need it, and I need it so seldom that I'll probably get it wrong anyway. When you re-explore the chunk, it will use the new worldgen parameters.

Huh. Nothing under /wc, either? I'm not near any of my gaming machines, so I can't look it up right at the moment, but if this topic doesn't get updated, I'll check it out this evening.

[Guimoute]

The pruning command in its current state is something that should not exist. Deleting chunks that have fewer than N modifications is a poor filter because, while it preserves your creations, it destroys parts of the landscale that you might very well consider "yours" even though you never modified a block there. The way it works is not suited for a world generation that changes between versions. 

I strongly advise against it for anyone who has a long term or permanent world. Explore further. Wait for a real tool that allows you to select chunks to prune on a map.

On 9/9/2025 at 9:10 PM, DrCopper said:

I recently attempted to solve essentially the same question, and, while I wouldn't try to explain exactly what each setting does, these are the commands that I used:

/worldconfig landcover 0.975

/worldconfig oceanscale 5

Thanks for that. 

On 8/31/2025 at 7:43 AM, kunchboy said:

To anyone who comes across this and is wondering the same thing, I did some experimenting.

Thank you. I think we were numerous in that situation, and the patch notes unfortunately did not explicitely provide an "update path". 

[Echo Weaver]

One can always try pruning on a copy of your world, but yeah, point well-taken. I've been playing on my world a long time. Probably just exploring outward is a better suggestion, but I'll take a look on a copy to see if that's horrendous.

So we have two sets of numbers on this thread:

landcover: 0.7
oceanscale: 1.0

and

landcover: 0.975 (that's very precise -- where did that number come from?)
oceanscale: 5 (not 0.5 right?)

Any reason to try one or the other?

[DrCopper]

1 hour ago, Echo Weaver said:

landcover: 0.975 (that's very precise -- where did that number come from?)
oceanscale: 5 (not 0.5 right?)

Any reason to try one or the other?

I'd say use these if you want to use what (I believe) are the new default settings for world generation since 1.21.

I arrived at these numbers after parsing the 1.21 changelog (https://www.vintagestory.at/blog.html/news/v1210-story-chapter-2-redux-stable-r420/), in particular the following block:

 

Quote

Feature: World generation tuning

• [...]
• Tweak: Enabled 2.5% ocean at 500% scale by default - walk far enough from spawn and you should find an ocean eventually  [Tip: in new game customisation, World Generation tab, set landforms % to less than 97.5% to have more ocean than this] 
• [...]

[Krougal]

70% wasn't bad, but I wanted more ocean. 30% wasn't what I wanted, small islands, large ocean. I settled on half.

 

[Guimoute]

I assume the new vanilla values were picked to make uncommon very large oceans. Reducing land cover and ocean scale should result in more water on average but more puddles. 

[Thorfinn]

On 9/12/2025 at 3:02 PM, Guimoute said:

Deleting chunks that have fewer than N modifications is a poor filter because, while it preserves your creations, it destroys parts of the landscale that you might very well consider "yours" even though you never modified a block there.

So modify a block there. Put down a dirt block somewhere that it will not stick out once it grows grass on it. Then prune works fine. Just use a parameter that matches the number of blocks you decided should "claim" a chunk.

[EDIT]

If you care about the traders you found, make sure you "claim" that chunk. Otherwise, they will be replaced with a different trader. Or, depending on what changed in mapgen, they might disappear entirely.

Edited September 14, 2025 by Thorfinn

[Guimoute]

I'm no putting a block in every chunk I want to save... 

[Thorfinn]

18 hours ago, Guimoute said:

I'm no putting a block in every chunk I want to save... 

Then prune is not the command for you.

Maybe something like /wgen regen?

[EDIT]

One of the things I really like about prune is if I get tired of the view from my homestead, I don't have to pick up and build elsewhere. I just prune and regenerate the world until I get the kind of scenery around me that I like.

Edited September 15, 2025 by Thorfinn

[Echo Weaver]

1 hour ago, Thorfinn said:

One of the things I really like about prune is if I get tired of the view from my homestead, I don't have to pick up and build elsewhere. I just prune and regenerate the world until I get the kind of scenery around me that I like.

If you're on the same version and seed, wouldn't the chunks always regenerate the same?

[Thorfinn]

Yes. What the trader is will change, but not the location of the wagon, but I believe even surface copper bits and crop seeds and berry bushes and trees will regen exactly where they were. Useful for replenishing flint in MP, mostly. I thought the question was about updating a 1.19 map in 1.21 or something like that.