Structure Lab v0.2.0 - Nebraska State Capitol

Structure Lab v0.2.0 — Nebraska State Capitol and large-build capture

A 185 × 130 × 185 vanilla-block Nebraska State Capitol, refined through three NBT → Minecraft screenshot → review iterations. The final model contains 253,376 non-air blocks, with 16 labeled views covering its exterior, gardens, public rooms, tower, and crown.

Downloads

• nebraska_state_capitol.nbt — standalone Java 26.2 structure template.
• nebraska_state_capitol.zip — vanilla datapack containing nebraska:state_capitol.
• nebraska_state_capitol.views.json — camera definitions for Structure Lab.
• nebraska_state_capitol_review.zip — all three iterations' Minecraft PNGs, contact sheets, manifests, and verification evidence.
• structurelab-26.2-0.2.0.jar — updated NeoForge mod.
• structurelab_mcp-0.2.0-py3-none-any.whl — updated local MCP server and authoring library.
• SHA256SUMS.txt — artifact checksums.

The exported Capitol needs no mods. Install the datapack into a Java 26.2 world's datapacks folder, run /reload, load a clear 185 × 185 site, and place nebraska:state_capitol with /place template. Exact commands, scale notes, references, and review history.

Lab changes

• Chunk-batched clearing and placement with progress reporting and recovery bounds.
• Streaming gzip NBT authoring with deterministic output and typed block-entity support.
• recapture_views creates a new screenshot set without replacing the structure.
• Per-view render-distance requests, restored after capture.
• Pause-on-focus-loss handling before placement; failed jobs stop pending placement work.
• A 16-million-position volume budget, one million explicit records, and a 32-million-position cleanup union.

The final Capitol placement and 16-view capture completed in about 54 seconds on the test machine. A camera-only recapture completed in 38 seconds with zero placement units. Verification compared 184 live block positions against the exported template, confirmed an all-vanilla palette and identical datapack payload, and checked removal of the previous successful runtime revision. A separate unmodded Minecraft 26.2 client loaded the exported datapack successfully and produced an additional exterior screenshot. The Java build and six Python tests passed. Maximum-volume and 1024-angle workloads remain unqualified.

Install or update the tools

Requires Minecraft Java 26.2, NeoForge 26.2.0.77+ for that game version, Java 25, and Python 3.11+. Tested with NeoForge 26.2.0.79 and Python 3.13 on Windows. Stop Minecraft before replacing the JAR; keep only one enabled Structure Lab version. Upgrade the wheel in the Python environment used by your MCP client.

• Install the mod
• Install and configure MCP
• Tool reference

The model interprets the supplied tour and floor plan at block resolution. Office details, murals, mosaics, and sculpture are simplified rather than exact reproductions. The lab still requires a graphical singleplayer client; entity templates, multiple palettes, simulation validation, dedicated-server/RCON operation, disk quotas, and automatic failed-revision pruning are not implemented.

Structure Lab v0.1.0 - Minecraft 26.2 / NeoForge

Structure Lab v0.1.0 — milestone 1

Generate Minecraft NBT structures through MCP, replace them in a dedicated superflat world, and automatically inspect labeled screenshots rendered by Minecraft.

Downloads

• structurelab-26.2-0.1.0.jar — install this into a Minecraft Java 26.2 NeoForge instance.
• structurelab_mcp-0.1.0-py3-none-any.whl — the separate local MCP server and Python NBT authoring library.
• SHA256SUMS.txt — checksums for both artifacts.

Installation

1. In Modrinth, create or select a NeoForge 26.2 instance and stop it.
2. Use Content → Upload files to install the JAR, then launch Minecraft.
3. Create a world using World Type: Structure Lab.
4. Install Python 3.11+ and the MCP wheel in a virtual environment.
5. Register the Python stdio server with your MCP client, pointing --connection at <instance>/structurelab/connection.json.

Full instructions:

• Install the mod
• Install and configure MCP
• Tool reference and authoring examples

Included

• Structure Lab superflat preset, local authenticated bridge, and MCP stdio server.
• JSON operations and a Python library for NBT generation, plus file import.
• Named view-pad metadata and sidecar camera definitions.
• Automatic sequential 1080p screenshots with labels, coordinates, angles, and revision identity.
• Replacement cleanup, previous-success screenshot retention until a new success, and clean NBT/datapack export.
• Furnished example house and scripts exercising real MCP tool calls.

Compatibility and limits

Requires Minecraft Java 26.2, Java 25 for the game, NeoForge 26.2.0.77+ for 26.2, and Python 3.11+ for MCP. Tested on Windows with NeoForge 26.2.0.79 and Python 3.13. The MCP process and graphical Minecraft client run on the same machine.

This is the first milestone. One active structure is supported, with a 2,000,000-position bounding-volume cap and 4,000,000-position cleanup-box cap. Horizontal dimensions may reach 1024, but height at the default origin is limited to 380. Up to 1024 angles are accepted by the schema; five-angle batches were tested. Large-scale performance, entity templates, multi-palette structures, RCON/dedicated-server operation, ad hoc recapture, simulation validation, and automatic failed-job pruning are deferred.

The build and five Python tests passed. The live MCP integration verified generation, replacement, five 1080p captures, invalid-input handling, and export. A separate unmodded 26.2 instance loaded the exported datapack successfully. Verification details.