Dimensions with lower build heights cannot properly have subworlds.

[The-Weeb-Guy]

Description

Theres a few mods where i see this behavior, being the Undergarden's undergarden and Pastels depths.

I originally found this issue when trying to make a airship inside of Pastels depths only for it to vanish completely upon assembly. This behavior also occurs in the Undergarden but slightly different.

To replicate go to either Pastels Depths or the Undergarden and place a swivel bearing, then place a block infront of it and assemble, the swivel bearing will lose its head upon assembly and when deconstructed the block will be gone. Same happens with physics assemblers where the entire object vanishes without being able to be recovered. The same occurs in the under garden except for when the assembler is placed on top, where the assembler will vanish but the blocks below stay, and trying to build up will hit you with a world height message.

Recordings of the issue in both dimensions

2026-04-19.21-54-13.mp4

2026-04-19.22-04-20.mp4

Game Log

https://mclo.gs/BXLoeod

[ryanhcode]

Thank you for the details!