nbtmapper

The client reads standard Minecraft structure .nbt files and uses the block palette and positions to keep only the topmost block in each X/Z column, which gives a flat map-art layout to build from. A state machine running on the client tick places the blocks in chained steps within a single tick, so a build proceeds efficiently. Fabric API is required, and the mod needs Fabric Loader 0.18.2 or newer and Java 21 or newer.

The mod is intended for map art and other creative building projects. It helps with movement, inventory management and block placement while a structure is loaded at set coordinates. A four-tab interface opens with the Z key, and settings are stored in the nbtmapper config files. Because it runs only on the client, it is meant for players in single-player or on multiplayer servers whose rules allow client-side building tools. The 1.0.0 build for 1.21.11 is published under All rights reserved and is not open source.