.mcstructure Editor — Bedrock Structure Files

Q: Can I resize a structure by editing size?

Not on its own — block_indices has one entry per position, so the array length has to match the new volume exactly. Changing size alone produces a file the game refuses.

Supports Minecraft Bedrock Edition and Java Edition — and every server core for both, popular or obscure: Vanilla, Paper, Spigot, Purpur, Folia, Fabric, Forge, NeoForge, Mohist, Sponge, Bedrock Dedicated Server, PocketMine-MP, Nukkit, PowerNukkitX, Cloudburst, Dragonfly, Endstone, LeviLamina and the rest. Full list.

A .mcstructure file is uncompressed little-endian NBT written by a Bedrock structure block. Drop one below to read its size, block palette, block indices and block entity data, edit any of it, and download the file back in the same encoding — which is what add-on and map makers need when a structure has to be patched without reopening the world.

Structure blocksBedrock add-onsBehavior packsLittle-endian NBT

Drop a .mcstructure file here

level.dat · .nbt · .mcstructure · .schem · .schematic · .dat · chunk dumps

Output format Compression

What is inside a `.mcstructure`

Tag	Type	What it holds
`format_version`	Int	Structure format revision, 1 in current files
`size`	List of Int	X, Y, Z dimensions of the captured volume
`structure_world_origin`	List of Int	Where the structure was captured in the world
`structure`	Compound	Everything below lives here
`structure.block_indices`	List of Int[]	Two layers of palette indices — normally blocks and waterlogging; `-1` means "leave whatever is there"
`structure.entities`	List of Compound	Entities captured with the structure
`structure.palette.default.block_palette`	List of Compound	Every distinct block state: `name`, `states`, `version`
`structure.palette.default.block_position_data`	Compound	Block entity NBT keyed by the flat index of the position

Indices in block_indices run X, then Z, then Y — a flat index of (x * sizeZ + z) * sizeY + y into the palette list. That mapping is what lets you fix a single mis-set block without regenerating the structure.

What people change here

Swap a block type everywhere by editing one entry in block_palette — every position pointing at that index changes with it.
Fix a block state such as a wrong facing or an accidental waterlogged in the states compound.
Strip entities that were caught by accident, by removing entries from the entities list.
Repair block entity data — chest contents, sign text, spawner settings — inside block_position_data.
Check the version stamp on palette entries when a structure imports with the wrong blocks after a game update.

Where the files are

Structure blocks save into the world's structures/ folder inside the world directory, in files named <namespace>_<name>.mcstructure. Behaviour packs ship them under structures/ in the pack, where the game loads them by namespace. Both are the same format and both open here.

Java Edition's equivalent is the gzip big-endian .nbt structure file — a different encoding with a different tag layout. The Java editor page covers those, and this editor opens them too.

Frequently Asked Questions

Can I convert a .mcstructure to a Java .nbt structure?

The editor can re-encode the bytes to big-endian gzip, but the tag layout differs — Java structures use palette/blocks with different keys and block names. A re-encoded file is readable, not a valid Java structure.

Why is my .mcstructure not compressed?

Bedrock writes structure files as raw little-endian NBT with no gzip wrapper. That is normal; the editor detects it as Bedrock raw.

What does an index of -1 mean in block_indices?

It marks a position the structure does not touch, so the existing block in the world is kept when the structure is placed.

Can I resize a structure by editing size?

Not on its own — block_indices has one entry per position, so the array length has to match the new volume exactly. Changing size alone produces a file the game refuses.

.mcstructure Editor — Bedrock Structure Files

What is inside a .mcstructure

What people change here

Where the files are

Frequently Asked Questions

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What is inside a `.mcstructure`