Custom structures using jigsaw blocks will not generate new pieces under Y-0
The bug
When a custom structure generates with underground or uses jigsaw blocks to generate underground, the custom structure will not generate any new pieces under Y=0, it will still generate pieces under Y=0 just not any new pieces. For an example: in the first picture, the structure is cutoff below Y=0 and is not generating, resulting in a cutoff in the deepslate layer.
I have attached a data pack that can be used to reproduce this issue below.
How to reproduce
- Download the data pack provided
- Create a new world with the seed -8285837402283326843
- Use /locate ms:catacombs and teleport to the location provided
- Go to the bottom floor of the structure and notice how no bottom paths are generated under Y=0 resulting in a cutoff effect.
Created Issue:
Custom structures using jigsaw blocks will not generate new pieces under Y 0
When a custom structure generates with underground or uses jigsaw blocks to generate underground, the custom structure will not generate any new pieces under Y=0, it will still generate pieces under Y=0 just not any new pieces.
I have attached a data pack that can be used to reproduce this issue below.
Steps to reproduce:
1. Download the data pack provided
2. Create a new world with the seed 6199744192621441902
3. Use /locate ms:catacombs and teleport to the location provided
4. Go to the bottom floor of the structure and notice how no bottom paths are generated under Y=0 resulting in a cutoff effect.
When a custom structure generates with underground or uses jigsaw blocks to generate underground, the custom structure will not generate any new pieces under Y=0, it will still generate pieces under Y=0 just not any new pieces.
I have attached a data pack that can be used to reproduce this issue below.
Steps to reproduce:
1. Download the data pack provided
2. Create a new world with the seed 6199744192621441902
3. Use /locate ms:catacombs and teleport to the location provided
4. Go to the bottom floor of the structure and notice how no bottom paths are generated under Y=0 resulting in a cutoff effect.
When a custom structure generates with underground or uses jigsaw blocks to generate underground, the custom structure will not generate any new pieces under Y=0, it will still generate pieces under Y=0 just not any new pieces. For an example: in the first picture, the structure is cutoff below Y=0 and is not generating, resulting in a cutoff in the deepslate layer.
I have attached a data pack that can be used to reproduce this issue below.
Steps to reproduce:
1. Download the data pack provided
2. Create a new world with the seed 6199744192621441902
3. Use /locate ms:catacombs and teleport to the location provided
4. Go to the bottom floor of the structure and notice how no bottom paths are generated under Y=0 resulting in a cutoff effect.
Custom structures using jigsaw blocks will not generate new pieces under Y0Custom structures using jigsaw blocks will not generate new pieces under Y-0
When a custom structure generates with underground or uses jigsaw blocks to generate underground, the custom structure will not generate any new pieces under Y=0, it will still generate pieces under Y=0 just not any new pieces. For an example: in the first picture, the structure is cutoff below Y=0 and is not generating, resulting in a cutoff in the deepslate layer.
I have attached a data pack that can be used to reproduce this issue below.
Steps to reproduce:
1. Download the data pack provided
2. Create a new world with the seed
61997441926214419023. Use /locate ms:catacombs and teleport to the location provided
4. Go to the bottom floor of the structure and notice how no bottom paths are generated under Y=0 resulting in a cutoff effect.
When a custom structure generates with underground or uses jigsaw blocks to generate underground, the custom structure will not generate any new pieces under Y=0, it will still generate pieces under Y=0 just not any new pieces. For an example: in the first picture, the structure is cutoff below Y=0 and is not generating, resulting in a cutoff in the deepslate layer.
I have attached a data pack that can be used to reproduce this issue below.
Steps to reproduce:
1. Download the data pack provided
2. Create a new world with the seed -8285837402283326843
3. Use /locate ms:catacombs and teleport to the location provided
4. Go to the bottom floor of the structure and notice how no bottom paths are generated under Y=0 resulting in a cutoff effect.
When a custom structure generates with underground or uses jigsaw blocks to generate underground, the custom structure will not generate any new pieces under Y=0, it will still generate pieces under Y=0 just not any new pieces. For an example: in the first picture, the structure is cutoff below Y=0 and is not generating, resulting in a cutoff in the deepslate layer.
I have attached a data pack that can be used to reproduce this issue below.
Steps to reproduce:
1. Download the data pack provided
2. Create a new world with the seed -8285837402283326843
3. Use /locate ms:catacombs and teleport to the location provided
4. Go to the bottom floor of the structure and notice how no bottom paths are generated under Y=0 resulting in a cutoff effect.
The bug
When a custom structure generates with underground or uses jigsaw blocks to generate underground, the custom structure will not generate any new pieces under Y=0, it will still generate pieces under Y=0 just not any new pieces. For an example: in the first picture, the structure is cutoff below Y=0 and is not generating, resulting in a cutoff in the deepslate layer.
I have attached a data pack that can be used to reproduce this issue below.
How to reproduce
- Download the data pack provided
- Create a new world with the seed -8285837402283326843
- Use /locate ms:catacombs and teleport to the location provided
- Go to the bottom floor of the structure and notice how no bottom paths are generated under Y=0 resulting in a cutoff effect.





Could you please replace your screenshots with ones using the night vision effect? Thanks!
Can confirm for 1.18.2 Release-candidate 1
@Michael Wobst I have attached new screenshots with the night vision effect.
This issue is fixed as of 1.19.