Changelog

The countryside comes alive. Farmland, grassland, and the plains OSM never mapped turn into real agricultural land: rotated field parcels that follow the road network, monoculture crop plots at different growth stages, wildflower meadows, dirt tracks, hay bales, and scattered rocks and bushes, with live pattern previews and a mix panel per land kind. Bundles the Arnis fork 3.0.4. Everything is additive and seam-safe: a project that never opens the Farmland drawer builds exactly as before.

A big usability pass focused on guiding people to run and build everything easily. The right rail becomes one three-step flow with a settings search and a single Generate button; the Projects gallery gains folders and a render queue that builds worlds one after another; borders can be built from any drawn shape; and a one-click launcher installs and starts Meld on Windows, macOS and Linux. Bundles the Arnis fork 3.0.3 (the 1.6 water and cave rendering fixes: uniform water colour, no thin land or road lines across water, no cave lava seams, and organic climate boundaries).

An above ground release to match the underground one. The bundled Arnis fork jumps to 3.0.1, matching upstream Arnis 3.0.0 feature for feature, and Meld puts the new world shaping options in front of you: bundled props placed at real map features, a visual chest loot editor, per world game mode and time of day, an in world map item, richer building facades, and a new global elevation source that replaces the old broken tile cliffs. Multi cell worlds still merge seamlessly: the shared origin grid and the position based rendering did not change.

The long-awaited underground release, and it is live. Worlds are no longer solid rock below the surface: one Caves toggle carves a full vanilla-style cave system into every cell at generation time, caverns, tunnels, rivers, lakes, ores, geodes and eight themed cave biomes, deterministic and seam-safe across tiles. Around it: an Export & compression suite that shrinks a finished world up to ~4.9×, a one-click Leaf server builder that turns the world into a running localhost server with the border plugins pre-staged, and the Border & zones Skript completing its real particle wall.

Real trees, shape the land, and bound a world to a country. Meld places a region-aware schematic tree pack instead of procedural trees: 1,959 hand-made models across 448 species and 10 world regions, chosen by location, scattered into natural groves, in five size tiers, anchored reliably on slopes and at water edges. Two terrain knobs make mountains as tall as you want without widening the map and put snow exactly where you want it. And Border & zones turns one or more countries into ready WorldGuard regions, point files, and a generated Skript that fences a server to that border.

Guided start, live tuning, and a benchmark report. Same engine (the Arnis fork is unchanged from 1.2.0), much easier to drive and to understand. The right rail is one numbered, guided flow, you can retune a run while it runs (workers, threads and CPU budget apply to the next cells), and every finished or stopped run drops a benchmark report into the world: machine specs, CPU/RAM and activity graphs, a per-worker timeline, and a Save-as-PDF. New projects start with fast first-build defaults, cell size is a free 1 to 64 fill-in, and the live CPU/RAM gauges read accurately now. Existing worlds and settings are untouched; the new defaults apply to new projects only.

Offline, faster, cleaner. Bake a whole region's OSM once from local Geofabrik .pbf files and generate with zero Overpass calls, with the OSM cache keyed to a fixed map grid so overlapping selections reuse tiles. The biggest per cell cost was a supplementary building fetch that ran even with buildings off; it is now skipped for roads only builds (a measured cell dropped from about 29s to 4s) and caches to disk when buildings are on. Your drawn area is remembered per world across a restart, and the diagonal water and sand wedges are fixed.

Go bigger, see more, waste nothing. The fork picked up an in process multi core engine and stream to disk, so a single cell can be huge. Map data now lives in one shared, visible folder reused by every world, and a per spawn cache walk that was quietly adding seconds to every cell is gone. Build a small area first to confirm your scale, elevation detail and save location before you commit a whole country.

The generator behind Meld 1.8 “Farmlands”, on top of the 3.0.x line (the upstream Arnis 3.0 merge and the 3.0.1–3.0.3 water, cave and climate fixes, see the GitHub releases). Every flag is additive and every decision is a pure function of world coordinates, so adjacent cells agree at their seams and default runs stay byte-identical.

• Field parcels. --field-mix splits farmland into five weighted styles (coarse / plains / flower / farm / moss) laid out as rectangular parcels with dirt-track boundaries. Orientation domains with noise-warped borders pick an angle and a layout (strips or blocky plots) and align to the dominant nearby road from a coarse road-bearing grid. Parcel sizes are real-metre and map-scale-bound; --field-scale zooms the pattern.
• Crop plots. --farm-crops weights seven monoculture plot kinds (wheat, potato, carrot, beetroot, sunflower rows, pumpkin patches, fallow). Per-field growth stages with in-field jitter, bird-sown stray-crop patches, hay-bale bundles, and terrain-aware sunflower fields that cluster in lowlands. Crop-planted farmland never decays; fallow uses a locked bare palette.
• Land coverage. --grass-texture and --land-texture extend the pattern to OSM grassland and to untagged satellite land (ESA WorldCover), each with its own mix (--grass-mix, --land-mix); villages get grassy ground. All textured styles carry vanilla-density cover: grasses, ferns, ten wildflower species, sunflowers, dead bushes, moss.
• Rock & bush scatter. --rocks / --bushes stamp 68 bundled schematics at random rotations, chunk-rolled (bushes ~5%, rocks ~2%), only on natural dry ground, never on water, roads or tilled fields.
• New blocks. beetroots, pumpkin, sunflower, packed mud, and six new flower species, wired through the Java, Bedrock and Luanti maps.
• Fixes. --snow-mode peaks ignores flat terrain (no more snow speckle on lowland plains), and the floating-vegetation sweep covers the new species so nothing hovers over rivers.

Underground update: one cave system, done right. The experimental cave engine is gone; --caves now runs a from-scratch Rust port of Minecraft 1.21.8 cave worldgen, carved directly into the filled ground at generation time. This is the engine behind Meld 1.5 "Meld Depths". Measured against 2.9.2: 31 files, +6,178 / −169 lines.

• Vanilla cave worldgen. The vanilla noise density field (cheese caverns, spaghetti tunnels, entrance pockets, pillars, noodle worms) sampled with vanilla's 4×8×4 cell interpolation, plus the random-walk tunnel and ravine carvers. Deterministic and seam-safe: every pass is a pure function of seed and position, so independently generated adjacent tiles carve the same caves at the seam.
• Water and lava that behave. Pool caves (multi-lobe, half-flooded, grand and coral-reef variants), long snake rivers that split into up to three streams and pour into caves only while descending, and a contained deep lava sea at the very bottom with obsidian and magma rims. Verified by a region auditor gating every build on zero floating fluid and zero water-lava contact.
• Ores, geodes and stone variety. The vanilla ore table (with deepslate variants at depth), three size tiers of stone-variant patches, and amethyst geodes cut correctly by cave air.
• Eight cave biome themes. Lush, dripstone, deep dark, mushroom, ice under mountains only, amethyst, volcanic at the bottom of the world, coral in water pools, about half the underground, with plain-rock buffer strips between zones. 72 new block definitions carry the coral, ice, snow and sculk sets.
• Cave asset packs. A cave-pack directory of schematic formations (ice spikes, dripstone columns, amethyst clusters, clay pool basins) stamped onto floors and ceilings, themed by zone, with block states preserved and rotated; formations sink into the ground, clip against walls, and never touch fluids. Caves generate fully without one.
• Biome mix control + layout preview. --cave-biomes takes per-theme percentages (100 = default share, 0 = off, 200 ≈ double) on a smooth curve that keeps the field seam-safe and the default byte-identical; --cave-zone-map renders the zone layout for a bbox to PNG overlays plus measured per-theme shares, using the exact picker generation uses. Meld's cave-biome preview runs on it.
• Cave polish. Deep dark gated to below the deepslate line (deep-only, like vanilla), and stone-variant patches (diorite/granite/andesite/dirt) placed surface-relative so they appear at any real-world terrain height, a valley region went from 4 diorite blocks to ~173,000.
• Cleanup. The old experimental cave engine (~3,900 lines) and its flags are removed, along with the Underilla pipeline hooks the new engine supersedes; the deepslate transition moved to its own small module and behaves identically.

Load your own tree models, and shape the terrain. A pack-agnostic schematic tree system and two terrain knobs on top of the 2.9.1 generator. It ships no tree art; it places whatever pack directory you point it at.

• Schematic tree packs. --tree-pack <DIR> points at a directory of .schem tree models plus a manifest, and places those models instead of the built-in procedural trees, a realm by location, a community by terrain, then a weighted species, blended with vanilla trees, inside the normal tree-spawn pass so density and clearings stay natural. --tree-sizes gates which height tiers may place.
• Vertical exaggeration. --vertical-exaggeration multiplies terrain height only, not the map footprint, so relief that flattens at small scales comes back.
• Snow modes. --snow-mode off|realistic|peaks|manual, the real latitude snow line, the top N percent of world height, or a fixed Y.
• Tree anchoring. Trees anchor on slopes and at water edges instead of floating, never root in water, and never clip into buildings.
• Small-scale water. Scale-aware river and pool depth, line-river width capped at small scales, a more varied riverbed, and trees swept off the water surface.

A maintenance release on top of 2.9.0. A cell can read its own slice of a shared OSM tile cache directly, with no per cell merge step, and a water rendering artifact that could flood a triangle of a cell is fixed.

• Read OSM from a tile directory. A new option points Arnis at a directory of grid tiles; it computes the tiles overlapping the bbox, loads each and de duplicates them, so a Meld orchestrator fills the directory once and hands the same directory to every cell with zero assembly.
• Water wedge fix. A water multipolygon with member ways missing for a cell left its outline open; the bbox clip then closed it with a straight chord and flooded a triangle. The clip now drops a broken outline instead of closing it with a fake edge, so the wedge is gone and proper water is kept. Verified on real data, with a wedge cell dropping from 135,600 to 4,555 water blocks and a clean river cell byte identical.
• Overture gated and cached. The supplementary building fetch runs only when buildings are on, and its index and byte ranges cache to disk, so a roads only cell no longer downloads building data it will not use.

Pulls the fork up to the upstream 2.9.0 line (53 merged commits, in process tile parallelization, stream to disk region eviction, the mimalloc allocator) while keeping the cross tile seam intact. Two independently generated overlapping cells agree block for block (0 of 1024 boundary chunks differ).

• Merged 53 upstream louis-e/arnis commits. In process tile parallelization, stream to disk region eviction, the mimalloc allocator, the large area warning and the GUI ETA, with the master origin tile invariant seam preserved through the merge.
• --no-buildings (alias --no-structures) drops all OSM buildings plus building adjacent features while keeping roads, rail, water, land cover and terrain, for a roads and ground only base layer.
• ARNIS_ELEV_ZOOM caps the terrain tile zoom for the whole run, so elevation stays lighter and hole free; a coarser zoom such as z13 still carries the full roughly 30 m signal while sidestepping the no data holes and downloading far fewer tiles.
• --download-terrain-only warms the AWS terrain cache for a bbox in one pass, and --offline (alias --elevation-cache-only) serves cache hits but errors on a miss instead of re downloading, so a batch run never quietly hammers the source.
• Parallel safe terrain fetch. Under Meld's roughly 64 concurrent fetches, cells were getting rate limited and truncated tiles that became flat seams. Fetch now uses 6 retries with backoff, deterministic per tile jitter, atomic cache writes and retry missing rounds, killing the staircase seam at the build center.
• Fixed an i32 corner sum overflow crash on far from origin master coordinates, plus the cross tile coordinate drift under master origin (longitude now anchored at the origin latitude so it maps to one block X project wide). Plain single world generation is byte identical.

Lets an external scheduler pre-fetch a region's OSM once and feed it to many cells, instead of every cell querying Overpass.

• --download-only. Fetches the OSM data to --save-json-file and exits before any world generation. Meld uses it to download the whole selection once, then passes --file to every cell, so parallel runs make zero Overpass calls and never trip the per IP rate limit. Purely additive, behaviour is unchanged when the flag is omitted.

Makes adjacent tiles agree at their shared borders, so the merge is visually seamless (~97% of rendered surface). All gated to --seed; single world output is byte identical.

• Trees, parks & vegetation meld. Scatter areas (forest, wood, tree_row, leisure, landuse) now decide each tile with a position seeded RNG instead of a shared stream consumed in flood fill order, so the scatter no longer relocates on one side of a seam. Scatter ways and relation members render unclipped (cap guarded) so both tiles flood fill an identical interior.
• Buildings. Multipolygon (relation) buildings no longer split at a tile border; buildings whose footprint is mostly water are skipped.
• Terrain. Elevation and land cover grids are sized with the world's origin anchored metric (no ~0.1% drift off OSM); robust parallel AWS fetch (more retries, retry missing tiles, atomic cache writes); the global outlier filter is skipped in tile mode (it caused a coastal border step).
• Biome. Cell local biome lookup plus a globally continuous chunk latitude removes the grass and leaf colour seam.

• Fixed cross tile coordinate drift under --master-origin-lat/lng. The longitude to block X factor was computed from avg_lat = (point + origin)/2, so one longitude mapped to different block X by latitude, shearing each tile off the region grid and leaving unrendered grass strips at seams. Now anchored at origin_lat, so tiles align exactly on region boundaries. Adds a latitude invariance regression test.

• Comprehensive underwater, shore and wetland rewrite: vanilla MC ocean floor (mostly GRAVEL, rare CLAY, SAND, DIRT patches), rare MAGMA and SOUL_SAND vents, domain warped organic shapes.
• Prominent dunes, sand to grass shore fade, wetland MOSS rings, tiered cattail with state stacked candles.
• --seed (alias of --tile-invariant-rendering) drives the global noise seed, so beds, dunes and shores are reproducible.
• A sweep pass removes vegetation left floating over water and roads.

• Tile invariant building rendering: pre clip bounds plus seeded salted RNG, so a building straddling two tiles renders identically in both.
• Global elevation min and max flags for cross tile Y normalisation, --master-origin global coordinates, --road-detail clean and compact modes, and --overpass-url override.