structura-render

Minecraft structures, rendered like Minecraft.

Turn a Java Edition Structure NBT into a polished PNG or a portable 3D model. structura-render reads the blockstates, models and textures from your own Minecraft client, so stairs stay stairs, doors keep their state, glass keeps its alpha and every export agrees with the preview.

Quick start

Install only the output you need:

pip install "structura-render[usdz]"

Render a showcase image and export the same geometry:

structura-render-hero house.nbt house.png
structura-export-usdz house.nbt house.usdz

For Minecraft 1.21.1, the standard launcher installation is detected automatically on macOS, Linux and Windows. To use another client or resource pack, point the renderer at its .jar or extracted assets/minecraft folder:

export STRUCTURA_MINECRAFT_ASSETS="$HOME/.minecraft/versions/1.21.1/1.21.1.jar"

The jar is extracted once into the user cache. Mojang assets are never bundled, copied into the package or redistributed.

Outputs

Extras can be combined:

pip install "structura-render[hero,usdz,gltf,obj,stl]"

Every command accepts .nbt. Legacy .schematic and Sponge .schem inputs are available through the legacy extra:

pip install "structura-render[hero,legacy]"
structura-render-hero castle.schematic castle.png

Preview conversion preserves the selection's bounds, authored air, block materials, connections and all entities. It does not apply datapack placement cleanup. Other Amulet input formats, including .litematic, are not currently verified by this library's conversion tests.

Texture-backed exporters fail clearly when client assets are unavailable, instead of silently producing a misleading result. For diagnostics only, the 3D exporters can retain the old coloured-cube fallback with --allow-flat-fallback. Hero renders expose the same choice as --no-textures.

The five 3D commands support --help without optional backends or Minecraft assets. PNG and USDZ do not require trimesh.

GLB and USDZ are single-file exports. For .gltf or .obj, keep the model together with its generated resources when moving or sharing it:

• glTF uses a <filename>.assets/ directory;
• OBJ uses an adjacent .mtl file and a <filename>.assets/ directory;
• resource filenames are derived from their contents, so exporting another model into the same directory does not overwrite the first model's assets.

The main glTF/OBJ file is published after its resources are written. Old resources are retained when a model is replaced, since another exported model may still reference them. Paths inside the export use relative, ASCII-safe resource names, including when the model's filename contains spaces or Unicode.

What makes the output faithful

• Client-driven models. Blockstate variants, multipart conditions, parent models, element rotations, UV rotation and UV locking come from the game.
• One geometry pipeline. PNG, USDZ, glTF, OBJ and STL share the same mesh builder, so format-specific implementations do not drift apart.
• State-aware special blocks. Chests, signs, banners, beds, heads, shulker boxes, bells, decorated pots, fluids and portals use compact textured models.
• Structure entities. Paintings, populated item frames, armor stands, dropped items and the vanilla entity catalog through 26.2 remain visible.
• Correct transparency. Per-pixel alpha is preserved for glass, foliage, bars, panes, water and other cutout or translucent surfaces. glTF and USDZ group geometry into opaque, cutout and blended materials. glTF explicitly requests nearest texture filtering; OBJ includes a grayscale opacity map.
• No stale cube list. Occlusion data is derived from client model geometry.

The generic resolver follows the client data rather than a short table of guessed blocks. New JSON-modelled blocks therefore work without adding another hardcoded shape to the renderer.

Choosing Minecraft assets

STRUCTURA_MINECRAFT_ASSETS accepts either:

• a Minecraft client .jar;
• an extracted assets/minecraft directory.

When the variable is unset, the renderer first looks for assets/minecraft in the working tree and then for a launcher-installed 1.21.1 client. Cached jar content is keyed by the jar path, size and modification time, so different versions do not collide.

Minecraft 1.13 and newer use the supported asset layout. The renderer is verified end to end with 1.21.1 and 26.2. This repository's own datapack targets Java 1.21.1, so use that client when exact project parity matters.

Honest limits

Entity rendering is static. The renderer does not evaluate animation, AI, item predicates, enchantment glint, armor trims or arbitrary display transforms. Entity previews preserve identity and silhouette; they are not a replacement for Minecraft's animated renderer. Block geometry still follows the client model pipeline described above.

The base install contains structura-core, NumPy and Pillow. PyVista, OpenUSD and trimesh are installed only by the output extras that need them.

STL contains geometry only. Its exporter welds vertices and removes duplicate triangles; an isolated solid cube produces a closed, outward-facing surface. Plants, intersecting shapes and open planes may still require repair or thickening before 3D printing. STL does not retain textures or transparency.

For implementation coverage and explicit dynamic-render limitations, see docs/block-render-audit-26.2.md.