Tileset Generator — Full Autotile Sets from a Few Pieces
A blob autotile set needs 47 tiles, but they are all made of the same few quarters. Give the Generator panel a small source block — an RPG Maker A2 block, a Blobsmith base, a five-tile strip or a single full tile — and it assembles the whole set, with the terrain bits already set.
A blob autotile set needs 47 tiles, but every one of them is four quarters, and each quarter has only five possible looks — so 20 drawn quarters are enough for all 47, or for the 16 tiles of a dual grid. The generator takes a small source block (an RPG Maker MV/MZ A2 block, a Blobsmith base, an A4 wall, a five-tile strip, or one full tile with a drawn rim), copies the quarters into every tile without scaling, sets the terrain bits, and keeps the new set linked so an edit to the source rebuilds every tile that uses it. It rearranges your pixels; it does not invent art.
- Godot 4 TileSetVerified· Godot 4.7.2
- TiledVerified· Tiled 1.12.2
- Unity 6 Rule TileVerified· Unity 6000.5.3f1 + 2D Tilemap Extras 8.0.3
- LDtkPartly verified· LDtk 1.5.3 schema + loader
Why 20 quarters make 47 tiles
Split a square tile into four quarters. The top-left quarter touches only three neighbours — the cell above, the cell to the left and the cell up-left — and those three decide its look: an outer corner when both sides are open, a rim along the top when only the cell above is open, a rim along the side when only the left is open, an inner corner when both sides connect but the diagonal is open, and full when all three connect. The other quarters work the same way with their own three neighbours.
Four quarters × five looks = 20 pieces. Every one of the 47 blob tiles is a particular choice of one look per quarter, so a source that contains those 20 pieces contains the whole set. A side-only source (an RPG Maker A4 wall) has no inner-corner look: 4 × 4 pieces, which give the 16 side tiles.
An RPG Maker MV/MZ A2 block is exactly such a source: 2 × 3 tiles where the top-left is a preview, the top-right holds the four inner corners, and the bottom 2 × 2 is a small box whose corners, edges and centre give the other looks. Blobsmith uses the same block with the two top tiles swapped. The generator knows both orders and a five-tile strip; the procedural rim kind draws a plain one-colour rim on one full tile instead.
Because pieces are copied, not resampled, every generated tile is byte-exact with its source quarters, and the Check panel says the art-vs-bits check does not apply. The same 20 pieces also build the 16 dual-grid tiles, since a dual-grid tile is four quarters of four different cells.
- Quarter
- One quarter of a tile (half its width, half its height); tiles need an even size in pixels to split.
- Look (state)
- Outer corner, top/bottom rim, side rim, inner corner or full: what a quarter shows given its three neighbours.
- Source block
- The few tiles you draw: A2 (2×3), Blobsmith (2×3), A4 wall (2×2), five-tile strip (1×5) or one full tile.
- Provenance
- For every generated tile, which source quarter each of its quarters came from.
Example: one tile, and the A2 numbers
The top-left quarter looks at N, W and NW; the other three quarters work the same way with their own neighbours:
N open, W open → outer corner
N open, W land → rim along the top
N land, W open → rim along the side
N land, W land, NW open → inner corner
N, W, NW land → full
5 looks × 4 quarters = 20 pieces → all 47 blob tiles, or the 16 dual-grid tiles
mask 28 = E4 + SE8 + S16 (land to the right, below, and down-right):
top-left = outer corner top-right = rim along the top
bottom-left = rim along the side bottom-right = full
RPG Maker MV/MZ A2 sheet 768 × 576 px = 8 × 4 blocks of 2 × 3 tiles at 48 px
one block = 96 × 144 px, one quarter = 24 × 24 pxThe Studio recognises a 768 × 576 sheet as an A2 sheet by its size and offers "Assemble from this block"; on the seamless CC0 coolschool floor the pixels alone said nothing (0.5), the size did, and Godot 4.7.2 painted all 485 test cells of the generated set as predicted.
What it does
- Quarter-exact assembly: every square autotile is four quarters, and each quarter depends only on its three neighbours, so 20 drawn quarters cover all 47 tiles. Quarters are copied, never scaled or blurred.
- Output as a blob-47 set or as the 16 corner tiles of a dual grid, from the same source; an RPG Maker A4 wall block, which connects by its sides only, gives 16 side tiles.
- The new set stays linked: paint on the source block and every generated tile that uses that quarter is rebuilt in one undo step. Hover a quarter to see how many tiles depend on it.
- An optional terrain-B tile adds the transition tiles for grass over dirt or water under sand — one pair of terrains at a time.
- Measured against Blobsmith Lite 1.0.4 on the same bases: 46 of 47 tiles byte-identical on the cave art and 47 of 47 on the RPG Maker A2 floor; the one difference is the isolated tile, which Nerulio builds from four outer-corner quarters.
How to do it
- Drop the sheet that holds your source block (an RPG Maker A2 sheet is recognised by its size).
- Open the Generator panel, choose the source kind and select its block on the sheet.
- Pick blob-47 or dual grid, add a terrain-B tile if you need transitions, and press Generate.
- Paint a test map (M) to see the set tile, touch up the source if a quarter looks wrong, then export for Godot 4 or Tiled (Ctrl+E).
Check the generated set
- Press M: the starter island should show outer corners, rims, inner corners and the peninsula without an outlined cell, with both the Godot and the Tiled rule.
- Hover a quarter of the source block: it says how many generated tiles use it. Edit it and every one of them is rebuilt in one undo step.
- The Check panel shows 47 of 47 (or 16 of 16) and says the art check does not apply, because the pixels come byte-exact from the source.
- Look at the isolated tile: Nerulio builds it from the four outer-corner quarters, so it is a small island with the rim you drew.
Source kinds and what the Generator makes of them
Pick the kind that matches the block you drew; sizes are in tiles.
| Source kind | Pieces you provide | What you get |
|---|---|---|
| RPG Maker MV/MZ A2 | 2×3 block: a preview tile, a tile of four inner corners, and a 2×2 box for the outer corners, sides and centre | Blob-47 or dual-grid 16 |
| Blobsmith base | 2×3 block like A2, with the inner corners in the top-left tile | Blob-47 or dual-grid 16 |
| RPG Maker A4 wall | 2×2 block that connects by its sides only | 16 side tiles |
| Five-tile strip | 1×5: isolated, full, inner corners, a horizontal strip and a vertical strip | Blob-47 or dual-grid 16 |
| Procedural rim | 1 full tile of the terrain; a one-colour rim is drawn along open sides, with round or square outer corners | Blob-47 or dual-grid 16 |
Troubleshooting
| Symptom | Likely cause | How to check | Fix |
|---|---|---|---|
| Error: tile width and height must be even | Quarters are half a tile; an odd size cannot be split | The grid's tile size, e.g. 15 px | Use an even tile size (16, 32, 48 px); pad or redraw the source |
| Inner corners appear where outer corners should, or the reverse | The wrong source kind: RPG Maker keeps the inner corners top-right, Blobsmith top-left | Which tile of the 2 × 3 block shows four small corners? | Switch between the RPG Maker A2 and Blobsmith kinds; in the Blobsmith comparison the Studio told the two orders apart (0.964 vs 0.852) |
| Seams across the middle of generated tiles | Quarters are copied as drawn; the source's pieces do not line up at the quarter lines | Hover the quarter: the count shows every tile that inherits it | Edit that quarter in the source; all dependent tiles update together |
| An A4 wall block gives only 16 tiles and no dual grid | Wall blocks connect by their sides only; there is no inner-corner piece | The set mode is sides | Expected; draw an A2-style block if you need corners |
| The transitions to a second terrain are missing | The terrain-B option makes one pair at a time | The Check panel lists the pair's missing patterns | Generate each pair (grass over dirt, sand over water) as its own set |
Other ways to do it
| Option | When it is the better choice |
|---|---|
| Blobsmith Lite (browser) | You want to draw the 2 × 3 base in a built-in pixel editor with a live playground. The free version exports a PNG sheet (47 blob or 16 sides); its itch.io page lists Godot .tres terrains and Tiled .tsx in the $9.95 full version (checked 2026-09-28). |
| RPG Maker's own autotiles | Your game is made in RPG Maker: it assembles A2 blocks itself, and there is nothing to generate. To take the art elsewhere, see RPG Maker autotiles in Godot. |
| Drawing all 47 tiles by hand | Every tile needs its own variation (cracks, plants) that four shared quarters cannot give; draw them in a pixel editor and let the tile workspace identify and check them. |
Engine exports and how each was checked
"Verified" means the exported files were loaded by the real engine or tool on real CC0 assets and the result was compared with the source. Anything that was not loaded is labelled as such.
| Target | Files | Check |
|---|---|---|
| Godot 4 TileSet | PNG · nerulio-tileset.json · nerulio_tileset_import.gd | Verified Godot 4.7.2The included import script builds the TileSet with terrain peering bits; a map painted with set_cells_terrain_connect equals the Studio preview in every cell on 9 corpus sheets. |
| Tiled | .tsx Wang set · sample.tmx | Verified Tiled 1.12.2Tiled's own readers load every Wang ID as written and the sample map renders pixel-exact. The terrain brush itself was not driven. |
| Unity 6 Rule Tile | nerulio-ruletile.json · Editor/NerulioRuleTileImporter.cs | Verified Unity 6000.5.3f1 + 2D Tilemap Extras 8.0.3Blob and side sets: a painted Tilemap shows the predicted sprite in every cell. Corner / dual-grid sets are not exported to Unity. |
| LDtk | .ldtk (1.5.3) · rules · sample level | Partly verified LDtk 1.5.3 schema + loaderAccepted by the LDtk JSON schema and its official loader, and the rules re-run to the exported tiles; not opened in the LDtk app. |
Evidence
Layouts identified from the pixels alone on the tile corpus: 4 blob-47 templates and 2 Wang templates with high confidence, a real 64 px cave tileset with medium confidence — every tile's bits right. Godot 4.7.2 painted every test cell exactly as the Studio predicted (485/485 per blob set, 251/251 on a 4-terrain dual-grid pack); Tiled 1.12.2 read every Wang ID back; Unity 6000.5 matched on every painted cell of the blob and side sets.
Limits
- It rearranges drawn pixels; only the procedural rim kind draws anything new, and that is a plain one-colour rim.
- Square quarters from even tile sizes only; isometric and hex tiles are not generated.
- Terrain transitions are generated one pair at a time.
- Tiled's terrain brush, the LDtk app and Godot's editor painter were not driven; the checks use the engines' readers and set_cells_terrain_connect.
- Unity gets blob and side sets only; several terrains become several Rule Tiles with no transitions between them.
- Isometric and hex tiles, animated tiles, occlusion and navigation layers are out of scope.
- Suggesting bits without a known layout needs a reference "full" tile; on side-only path templates the guess can fail until you select it.
Versions and sources
Behaviour from src/game/tiles/generator.js and docs/STUDIO-TILE.md. Measured on 2026-09-23 against Blobsmith Lite 1.0.4 on the same bases: 46 of 47 tiles byte-identical on the cave art and 47 of 47 on the RPG Maker A2 floor; Godot 4.7.2 painted the generated coolschool set 485 of 485 cells as predicted. Blobsmith's features and price are from its own itch.io page, read on 2026-09-28.
Official documentation used
Questions
Does it draw new art for me?
No. It only rearranges the pixels you drew; each generated tile is four quarters copied from your source. The procedural rim kind is the one exception: from one full tile it draws a plain one-colour rim along the open sides.
Will my RPG Maker (MV / MZ) autotiles work in Godot?
Yes, as a generated 47-tile set. On a seamless CC0 A2 floor the pixels alone told nothing (score 0.5), the sheet size named it A2, the set was assembled, and Godot 4.7.2 painted all 485 test cells as predicted.
How is this different from Blobsmith?
Both assemble a 47-tile sheet from a 2×3 base. Blobsmith Lite writes Godot .tres and Tiled .tsx only in its $9.95 version; here the terrain data for Godot 4, Tiled, Unity and LDtk comes with the export. Blobsmith puts the inner corners top-left, RPG Maker puts them top-right — both orders are offered.
Is it free, and do I need an account?
Everything on these pages is free and works without an account. There is no watermark and no export that is held back.
Are my sprites uploaded?
No. The Studio decodes, packs and exports in this browser tab. Projects are autosaved in the browser (IndexedDB) and can be saved as a .nerulio file.
Does it need Aseprite or an engine plugin installed?
No. .aseprite files are read and written in the browser, and each engine bundle carries what that engine needs (for Godot, the import settings and scene; for Unity and the Godot TileSet, a small editor script).