[MC-241592] Trees can be cut off at new chunk boundries when upgrading a world to caves and cliffs world generation

The Bug

Just before 21w43a came out, the snapshot where terrain blending is added, I posted a feedback about 21w42a that mojang has already applied chunk blending for 1.17 worlds on trees, corals, and structures. The next day, I checked the newest snapshot. I recovered my 1.17 world and opened it in the snapshot to see how the chunk blending is applied, and discovered trees are split in half again. It mainly happens when the 1.17 biome is dark forest. I can confirm this bug for 21w44a and 1.18 Pre-release 1. On the bottom left of the photo you can see the version of the world.

Reproduce

Create a world in 1.17.1 or lower
Go to a biome with trees
Close and open the world in 1.18 pre-release 1 or higher
Go towards the new chunks

Observed Result

The trees were cut in half

Expected Result

The trees would not get cut in half

Related issues

is duplicated by

MC-241759 Floating vines and leaves generate when upgrading world to 1.18

MC-242874 Leaves on trees cuted

relates to

MC-185253 Decorations at chunk borders ignore saved biome information from partially-generated chunks

MC-224729 Partially generated chunks are not saved in some situations

Attachments

Comments

migrated 2021-11-15T11:12:41Z

[media][media][media][media][media][media]

migrated 2021-11-15T16:11:11Z

Chunk blending for trees was never actually a thing. When the tree generates in the newer chunk, it spreads to the old chunk, but when the tree generates in the old chunk, it doesn't spread to the new chunk. I can however confirm for 1.18 Pre-1. Relates to MC-125007

migrated 2021-11-15T17:04:19Z

@Dmitry Konev You can see the pictures. They proove it was in 21w42a

Moesh 2021-11-16T15:46:52Z

Please supply your un-upgraded world and coords, if possible. This will help speed along the process.

migrated 2021-11-18T12:55:51Z

It is unfortunately not possible to share files bigger than 10MB. The world is 32MB. But as I said, it happens mainly on dark forests. It doesn't happen on for example taiga.

migrated 2021-11-18T12:56:23Z

You can attach the Google Drive link to your file instead

ampolive 2021-11-19T13:04:26Z

This seems related to MC-185253.

bdm68 2021-11-19T21:29:45Z

MC-241216 has a world save "S3-1171.zip" saved in 1.17.1 that exhibits the issue after upgrading. Cut-off trees can be found at -57 32 and -32 33.

migrated 2021-11-24T16:51:55Z

Didn't manage to test this for Pre release 6 and 7 in time, but it is still in the game at Pre release 8

migrated 2021-11-25T19:55:43Z

Still in release candidate 1

migrated 2021-12-02T17:16:22Z

Can also affect structures such as village houses when at the edge of a chunk

migrated 2021-12-04T17:11:26Z

@Bug bug it doesn't. The bug is caused by the way how tree generation changed from the newest update. On 1.17 it generated dependend on the seed. In the newest update it generates randomly. So the only way to fix this bug I think would be to implement a bit of the old generation inside 1.18's code.

migrated 2022-03-01T18:11:22Z

I wonder if people would still notice this bug since everyone updated their world already. They might save this bug for when the next world generation update is coming and this biome blending is applied to that.

[Mod] Jingy 2024-01-05T22:13:48Z

Can confirm in 1.20.4 and 23w41b:

[media]

[Mod] Jingy 2024-01-15T03:24:42Z

Can the title be changed to something like:
"Trees can be cut off at new chunk boundries when upgrading a world to caves and cliffs world generation"

Mr_Quasi 2024-12-06T20:49:49Z

Can confirm in 1.21.4, but strangely enough this doesn't apply to dark oak forests, they regen normally (maybe to do with new pale garden terrain generation?)