Mirror Measure

Find the missing block, wrong material or incorrectly facing stair in an existing symmetrical build.

Use

Server operators (permission level 2) run /mirrormeasure scan <x1> <y1> <z1> <x2> <y2> <z2> x states. Use z to reflect across Z instead, or blocks to compare block types without orientation. Coordinates support normal Minecraft relative notation. The plane is always the midpoint of the selected cuboid: odd widths include a center layer, even widths reflect between layers. The X option reverses X coordinates; Z reverses Z coordinates.

Example: /mirrormeasure scan 0 64 0 9 70 9 x states checks a ten-block-wide build across its middle. /mirrormeasure page 2 shows the next eight mismatch pairs from your last snapshot. Snapshots are not live; rerun the scan after editing.

State mode uses Minecraft's own block-state mirror transform. Block IDs, air/block differences and state/orientation differences are reported separately. Block-entity contents, inventories, sign writing and entity positions are deliberately ignored. There is no placement, hologram, automatic repair or world mutation.

Work is bounded to 4,096 pairs, 8,192 cells, maximum 128 blocks per axis and a five-second cooldown. Unloaded chunks and invalid heights are skipped with an explicit INCOMPLETE report; no chunks are loaded. At most 32 recent player reports remain in memory, with older entries evicted. Reports clear on server restart. Operator access can reveal block information across claims; this does not implement claim permissions.

Versions

• NeoForge 1.21.1, Java 21.
• NeoForge 26.3, Java 25.

Install on the server or matching singleplayer instance. Multiplayer clients do not need it. Files are not interchangeable.

Provenance and license

MIT, Copyright 2026 RickCode. Loader scaffolding and command cooldown support reuse our MIT Airspace Survey and Field Tally code. The reflected pairing, block-state comparison and paginated mismatch functionality were written for Mirror Measure. It neither includes their survey/crop-audit features nor requires either mod installed. MIT notice is included in each file.

New beta release; bugs may remain. Both NeoForge builds passed exact-artifact dedicated-server startup and 44 gameplay assertions per target. 563,861 core assertions passed on each of Java 17, 21 and 25. Graphical client testing has not been performed.