The bug
Some surface biomes can still appear 3D due to biome smoothing also being applied on the Y axis, causing them to vertically intersect. Even if this was previously intended, this should no longer be the case as described below.
Expected result
Only cave biomes should be 3D, as per the 21w40a changelogs:
— Non-cave biomes no longer change with height - so no more savannas in the sky and things like that
Side effects
Grass, dirt, sand, sandstone, stone, and ores generate in the middle of hoodoos, as blocks of other hot biomes replace them. Partially fixed with the fix of MC-241539, but still happens.
Sand and sandstone generate in improper places, as beaches and snowy beaches intersect other biomes.
Foliage such as grass and certain leaves change color on mid-air.
Water color randomly changes with height (MC-237312), due to surface biomes with different temperatures being sandwiched in between cave biomes. Resolved as "Works As Intended".
This could also be a nuisance for certain mob farms, as you'd have to constantly check the F3 screen if the biome is the correct one vertically.
Other biomes overlapping mushroom biomes cause mobs to spawn in them, making this bug an aggravating factor of MC-93271.
Visual analysis
[media]Analysis of an intersection between desert, savanna and eroded badlands biomes. I placed a terracotta block where the biome was eroded badlands, dirt where it was a savanna and sandstone where it was a desert. The original screenshot is also attached.
To reproduce
Seed: 7394312107885230768
Coordinates: /execute in minecraft:overworld run tp @s -2423.43 82.00 6396.92 -145.66 57.90Linked issues
is duplicated by
relates to
Attachments
Comments
ampolive
syarumi
How's this different from MC-238804? Describes the same issue, which is biomes overlapping at their edges.
ampolive
This was supposed to be changed in 21w40a, so that only cave biomes would be 3D, from the changelogs:
— Non-cave biomes no longer change with height - so no more savannas in the sky and things like that
That does not happen though. But you're right that it is essentially the same issue. Maybe this should be resolved as a duplicate and that ticket should be reopened.
ampolive
Can confirm in 21w44a.
ampolive
May I request ownership of this ticket as the original reporter is inactive? Relates to MC-209558.
ampolive
Clones MC-173878.
found a bug were cave biomes dont work right
May already been fixed. Correct me if I'm wrong
ampolive
Not fixed.
Maity
It would be nice to have the sky biome.
Ceresjanin123
Can confirm in 1.18 Pre 5
Seed: -4542431585794183865
Location X Z: 2140 1995
Updates not even nearly ready😞 if the devs go on for the 30th
Unless there trying 3D again but not working as intended if so when they do I will be very happy loved mixed cliffs
Ceresjanin123
This is actually pretty important because it causes MC-241539 even after the fix
I can confirm that this still occurs in 1.18 Pre-Release 5.
This issue still occurs in 1.18 Pre-Release 7. In the screenshot I attached to this report, I stacked two jungle leaf blocks on top of each other. The bottom block is in a beach biome and the top block is in a taiga biome.
This issue still occurs in 1.18 Pre-Release 8. The player can reliably reproduce it by going to a border between two biomes, opening the F3 screen, and flying up or digging down.
the values stay the same based on how high it stays so multi noise is not to blame for biome bug
ampolive
@unknown You are correct, the multinoise values don't seem to change vertically for overworld surface biomes, so something else is causing this bug.
Great visual analysis! It puts the issue into perspective very well.
@unknown The "something else" is just the smoothing out of biome borders since 1.15; rather than saving the biome for each block, it's saved for every 4x4x4 blocks, and borders smoothed after loading it. It's the same smoothing as on XZ axis.
ampolive
@unknown I see, thanks.
Dhranios thanks for the helpful info!
I am a bit confused, though. When I first found out about this bug, I tried to reproduce it in a 1.17.1 singleplayer world, but I was not able to. How rare was this bug pre-1.18?
It may have been less extreme, but it was definitely there.
Oh ok, thanks for clarifying!
Unrelated, but I can confirm that this issue still occurs in 1.18-rc3.
This still occurs in 1.18-rc4.
Also, I believe the large biomes setting makes this bug more severe. I was playing in a large biomes world and noticed that between a taiga biome and a river biome, there was an 8-block wide zone and an 11-block wide zone in which going up or down switched the biome between taiga or river.
I haven't done much testing, so I don't know for certain that large biomes intensifies the bug, but I believe it does because I don't remember seeing such large transition zones in default worlds. In default worlds, these zones where moving vertically changes the biome seem to be only a few blocks wide, though it is possible they are wider and I just didn't notice.
If this bug is fixed in a future version and I upgrade a world from 1.18 to that future version, will the vertically changing biomes still be in the world? I'm thinking they won't be, since the biome blending is applied after loading, but I just want to make sure before starting any long-term 1.18 worlds.
It should change then, as th biome is saved per 4x4x4 blocks, if y changes no longer change blending, the save data shouldn't have to change.
1.18.1 pre 1
Something I noticed about 1.18 is that, according to my experimentation, it fixes the root cause of MC-209558, since client biomes now seem to match server biomes. I believe this because in a newly generated chunk in a 1.18 server, I found a badlands hoodoo with stone in it. When I investigated, I found that the stone corresponded with a river biome while the terracotta corresponded with the badlands.
However, because of this vertical biome smoothing bug, the effect of MC-209558 (biomes changing by y-level) still persists, except that this is present both client-side and server-side.
Confirmed for 1.18.1.
Can confirm in 22w03a.
To add to the complaint list, this makes mobs spawn on blocks that otherwise seem to be within the boundaries of a mushroom island.
Don’t know if this is to do with this but if you use datapacks to change cave biome noise settings it reverts part of the area to surface biomes not the set cave biome
No, that's not related.
It works both above ground and below
as well as to the side
Sure the random cave biome Y range is cause by this this because if you set biome range to a fixed y range only it still does it
Cries
I've noticed monsters spawning on mushroom biomes and MiniHUD showed ocean biomes are often created above mushroom biomes, especially around the edges of the mooshroom island. I suspect this bug report is related.
[media]
ampolive
@unknown That bug is being tracked in MC-93271.
Can confirm in 23w07a.
Can confirm in 21w43a. This causes hoodoos in badlands next to deserts to generate with stones, ores, dirt and sand. This could be intended though, as a side effect of this bug was resolved as "Works As Intended" (MC-237312).