I tried to generate custom flat world in my server.(just small and for testing)
So i wrote generator setting format like below
"biome"\:"minecraft\:sparse_jungle","layers"\:[{"block"\:"minecraft\:bedrock","height"\:1},{"block"\:"minecraft\:deepslate","height"\:63},{"block"\:"minecraft\:stone","height"\:63},{"block"\:"minecraft\:dirt","height"\:7},{"Block"\:"minecraft\:grass_block","height"\:1}]
When i entered server, grass block didn't generate.
So i opened server.properties and checked again but there wasn't any problem(in my opinion)
I guessed that there's problem in world and opened level.dat with NBT Explorer.
In level.dat, grass block layer changed to air layer.
So i tested generating world a lot.(without grass layer, adding one layer, etc.)
Then i could know about some problem about generating layers.
When layers are more then 5, fifth and upper layers are change to minecraft:air.
I think this is one of bug in paper.
I want fix this bug.
Version : MC 1.19.4 / Paper 1.19.4-513
So i wrote generator setting format like below
"biome"\:"minecraft\:sparse_jungle","layers"\:[{"block"\:"minecraft\:bedrock","height"\:1},{"block"\:"minecraft\:deepslate","height"\:63},{"block"\:"minecraft\:stone","height"\:63},{"block"\:"minecraft\:dirt","height"\:7},{"Block"\:"minecraft\:grass_block","height"\:1}]
When i entered server, grass block didn't generate.
So i opened server.properties and checked again but there wasn't any problem(in my opinion)
I guessed that there's problem in world and opened level.dat with NBT Explorer.
In level.dat, grass block layer changed to air layer.
So i tested generating world a lot.(without grass layer, adding one layer, etc.)
Then i could know about some problem about generating layers.
When layers are more then 5, fifth and upper layers are change to minecraft:air.
I think this is one of bug in paper.
I want fix this bug.
Version : MC 1.19.4 / Paper 1.19.4-513