Hostile Mobs will not spawn at certain heights if the darkness they would spawn in is caused by the night. So if the skylight is 0 mobs WILL spawn at these heights.
The heights are:
16, 32, 48, 64, 80, 96, 112, 128, 144, 160, 176, 192, 208, 224, 240
(basicly every 16*n)
I guess this is due to the fact that Chunks are split up vertically in parts with the height of 16. So the problem occurs if a mob spawns inside one part, but the block it spawns on is inside the part below.
How to reproduce:
1. Singleplayer
2. Create new World
3. Gamemode: Creative
4. More World Options...
5. World Type: Superflat
6. Customize
7. Presets
8. paste the following preset into the box at the top: 3;64*minecraft:stone;1;
9. Use Preset
10. Done
11. Create new World
12. set the time to night (/time set 18000)
No mobs will spawn!
You can use the preset 3;63*minecraft:stone;1; or 3;65*minecraft:stone;1; instead and they will spawn.
Linked issues
is duplicated by 4
relates to 3
Attachments
Comments 6
Maybe this is the cause of MC-42053
Kumasasa - I'm wondering that myself, much testing I've done in looking at the spawn rates were in either plains or deserts due to visibility, but that would also put a lot of the territory around these levels.
Confirmed for 14w21b for height(Y) 64 no mobs are spawning
In a area of 50*50 (2500 blocks; height 63!) 74 mobs spawned in 3 seconds!!!
Definitly a massive bug
*Added screenshot
Nathan Adams
Confirmed with Superflat preset "Overworld": A single skeleton spawns but on a beach on level 63:
World with height 64 spawns a lot of mobs: