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@Querz
Last active Jun 20, 2022
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Tips and Tricks regarding Minecraft 1.16

Tips and Tricks regarding Minecraft 1.16


WARNING: The following instructions are deleting parts for your Minecraft world. Make sure to create a full backup before proceeding with any of those steps!


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Deleting chunks based on a selection

Usually, the Nether does not contain too many builds. Most of the time it's a Nether highway or some Nether mob farm. Knowing where those farms are located might help with the process, but MCA Selector should give a relatively clear overview of the Nether.

A selection can be made by left-clicking either chunks (when zoomed in) or entire regions (when zoomed out). Holding and dragging works too.

Making a selection in MCA Selector

Deleting the selected chunks

To delete the selected chunks, use Selection --> Delete selected chunks. Opening the world in Minecraft and travelling to those chunks will regenerate them using Minecraft's current terrain generation.

MCA Selector's deletion warning

Keeping the selected chunks

To keep the selected chunks and delete everything else, use Selection --> Export selected chunks. This will ask you to specify a folder where the selected chunks should be exported to. The selected folder must be empty. When the export is complete, delete the MCA files of your world from the region folder and move the files from the export to your region folder. The region folder for the Nether is located in world-name/DIM-1/.

MCA Selector's export warning

Deleting chunks based on a filter

Automatically filtering chunks is particularly useful for very large worlds, especially when you are running a server with lots of players.

A filter can be used to select, delete or export chunks based on a few conditions, for example the time players have spent in specific chunks or the blocks a chunk contains.

Opening the filter tool

Open a world and navigate to Tools --> Filter chunks. This will show an example query that will select all chunks from x/z -1600 to x/z 1600. Below the filter is a text field, where a textual representation of the query is shown that can also be used in headless mode. To use a textual query, insert it into the text field and press Enter. If the query is valid, it will parse and show it in the query editor above.

Examples: Query all chunks where players have spent more than 5 minutes in total:

InhabitedTime > "5min"

Filter tool with query InhabitedTime = 5min

Query all chunks where players have spent more than 5 minutes in total, contain a chest block and where chunk-x is smaller 3000:

InhabitedTime > "5min" AND Palette contains "chest" AND xPos < 3000

Filter tool with query InhabitedTime = 5min AND Palette contains chest AND xPos < 3000

Note xPos and zPos are chunk coordinates, not block coordinates. To convert block coordinates to chunk coordinates, divide them by 16.

The Filter window also has a few options at the bottom to either first create a selection as if using right-click to select the chunks on the map, to delete the chunks that test positive for your query directly or to export those chunks to a new empty folder.

Partially deleting chunks

A chunk is made of 16 vertically stacked sub-chunks, called Sections. Sections are indexed from 0 (lowest) to 15 (highest). This especially comes in handy when farms and highways are built above the Nether ceiling, because there is a relatively clear cut where the generated Nether ends and where the builds start.

The simplest (but also most unpredictable) method to keep builds above the Nether ceiling but regenerate everything below is to delete all Sections from 0 to 7 and setting the Status field of the chunk to empty.

Deleting sections 0 to 7 and setting Status to empty

This might have some unwanted (or wanted) effects on generated structures, such as Fungi forests or Basalt deltas. Structures from basalt deltas will generate on top of structures on the nether roof, while they will not generate below:

Basalt deltas generating on top of the nether roof while missing below

Partially importing chunks

Chunks can also be partially imported. This is more reliable than deleting and regenerating sections as described above and theoretically allows to also keep builds below the Nether ceiling, but might also result in a lot more work.

To make this work, all chunk we want to import need to have the same DataVersion as the chunks we want to merge them with. The simplest way to do this is to use Minecraft's "Optimize World" feature. The image below shows a Nether highway in our freshly upgraded 1.16 world:

Freshly upgraded nether highway

Next, we will export our highway. Use the method of your choice to make a selection, and export. Here's how the exported nether highway looks like:

Exported nether highway

Then, we open Minecraft and generate all the chunks we need to import our Nether highway. The newly generated chunks look like this:

New nether highway chunks without nether highway

After we did that, we import our Nether highway into our new chunks with the following settings:

Nether highway import settings

  • Offset: We currently don't care about an offset, so we leave it blank.
  • Overwrite existing chunks: Yes, otherwise we won't import anything because all the target chunks are not empty.
  • Apply to selection only: No, because we don't have a selection.
  • Sections: The Nether highway in this example is directly below the bedrock ceiling, so we want to import the section with index 7 and everything above. The section with index 7 starts at Y=112.

Hitting OK and waiting for a second rewards us with this:

Nether highway import successful

Alternatively it is also possible to create a selection first and only allow the chunk import to insert chunks at your selection, to make sure that that import only merges chunks into already generated chunks.


@carthradge4
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carthradge4 commented Jul 2, 2020

Thank you! This is amazing. Maybe add some details on what happens when doing the Partially deleting chunks option. It's cool since it generates basalt deltas or trees on top of any buildings you have above the roof, without deleting any blocks.

@Querz
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Querz commented Jul 3, 2020

I couldn't make any of the Huge Fungi to generate on top of the Nether roof, but the basalt deltas. Under certain conditions mushrooms, roots and nether sprouts will generate when there is warped or crimson nylium. It will also not generate any huge fungi below the roof when it generates mushrooms, roots or nether sprouts. Same for basalt deltas.

I changed that section a bit and added a screenshot to better show the consequences.

@lolofome
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lolofome commented Aug 26, 2020

Hello I have a question regarding "Partially importing chunks", the thing is that my nether highway is between Y=47 and Y=52, and not directly below the bedrock ceiling, so I assume that i shouldn't use the section with index 7, but i don't know what "section index" i have to use and i can't find anything online regarding chunk sections.
Sorry if broken english, and if this wasn't the correct place to ask these kind of questions. Also thanks if you read this.

@Querz
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Querz commented Aug 26, 2020

Open Minecraft and press F3 to open the debug screen. The number you want is this one:
Screenshot 2020-08-26 at 09 14 00

To make it easier to see the borders, you can toggle chunk borders with F3+G. The blue lines indicate the borders for chunk sections.

When importing chunks partially, make sure that both the imported as well as the chunks you import to, have the exact same DataVersion (you can achieve this by upgrading both to the newest version using Minecraft). And in case something goes wrong, create a backup first :)

@lolofome
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lolofome commented Aug 26, 2020

Thank you man I really appreciate your response

@bloxanne123
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bloxanne123 commented Oct 20, 2020

Is there a way to keep certain chunks in a different way? I have some highways, and I just want to keep those. Is it possible to invert the logic so that instead of deleting selected chunks, it'll keep them? I don't want to mess around with importing and exporting. Ditto for the Overworld.

@Querz
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Querz commented Oct 20, 2020

You can invert a selection using Selection --> Invert selection after selecting the chunks you want to keep, then delete everything else. Make sure to have a backup of your world before deleting any chunks!

@OrionH
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OrionH commented Jun 20, 2022

I have made some section range changes to update for 1.18 and added a line specifically for 1.16 since this is a "tips for 1.16" document.
Check out my fork since I can't create a PR on a gist.

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