Using Microsoft-Decision-1 (out yesterday) to fill 3D indoor levels with assets

LevelDez, a browser-based 3D level editor released by developer yeme-oss, uses Microsoft's Decision-1 model — released the day before — to answer calibrated yes/no probabilities that the tool converts into button presses for furnishing indoor spaces, with a full autopilot run costing roughly a tenth of a cent. The project ships with about 600 hand-built Blender assets in a gothic necromancer academy pack, exports a JSON layout plus a multi-mesh GLB, and requires Node 18+ with zero npm dependencies, loading three.js from a CDN. Two optional keys, OPENROUTER_API_KEY for Decision-1 and GEMINI_API_KEY for regenerating wall art with Nano Banana at approximately $0.034 per image, are not required for the editor to work.

Design richly furnished indoor spaces in your browser, hand the boring parts to a yes/no AI , and export a JSON layout plus a multi-mesh GLB your engine can load. demo.mp4 demo-scifi.mp4 Greyboxing a believable interior is slow: a floor plan, forty doors, a hundred props, lighting, and the hundred small decisions that make a room feel lived in . LevelDez automates those decisions with a small, cheap model and a library of real assets, and keeps you in control with an ordinary editor and undo. - 🏰 One sentence → a whole building. Corridors, side wings, big halls and rooms of every size, furnished, lit and decorated. - 🧠 A yes/no model as the "hands". Microsoft Decision-1 answers calibrated probabilities. LevelDez turns them into button presses a full autopilot run costs roughly a tenth of a cent . - 🎨 Every room has an identity. Per-room wallpaper or stone, floor, wainscot, trim and a coloured mood light, chosen to suit what the room is . - 🪑 Rooms are composed, not sprinkled. Reading nooks, altars with candelabras, lab benches with cauldrons, crypt rows, classroom rows, ritual circles. - 📦 ~600 hand-built assets a complete gothic necromancer academy pack , built in Blender, loaded lazily so the editor stays fast. - 🎬 Cinematic viewport. Ambient occlusion, bloom, colour grading, dust, flickering candlelight and soft shadows. - 🧰 Zero npm dependencies. One small Node server and static files. The quickest is that you vibe your own stuff took me a few hours , but I'm sharing my project so that my claims are not empty-handed and it can be tried out. git clone https://github.com/yeme-oss/LevelDez.git cd LevelDez cp .env.example .env optional: add your keys see below npm start - http://localhost:5173 Requires Node 18+ . No npm install is needed. three.js is loaded from a CDN, so the first load needs an internet connection. Then, in the browser: 1. Click Generate layout choose small / medium / large in the header. 2. Open the Decision tab, tick all rooms and press Autopilot . 3. Orbit with the mouse, click props to move them, Export GLB when you are happy. Prefer to drive it with words? Type this into the Go box instead: Generate a large, complex gothic necromancer academy: a main corridor with side corridors and many rooms of varying sizes classrooms, dormitories, libraries, alchemy laboratories, a crypt, a ritual chamber, chapels and a grand hall . Use the gothic style and asset pack, give every room a different wallpaper and floor, and furnish it richly with composed setups, gothic architecture pillars, window tracery, ceiling vaults, cobwebs , candlelight and lighting, curtains, paintings and tapestries on the walls, decorated surfaces and lived-in clutter. then press Autopilot all rooms to let Decision-1 finish what is still missing. The same prompt is saved in promptGO.txt https://github.com/yeme-oss/LevelDez/blob/main/promptGO.txt . Both keys are optional . The editor works without them. | Variable | Used for | Without it | |---|---|---| | OPENROUTER API KEY | Decision-1: the Go box, Autopilot , Critic , Ask and per-room theme choice. The key stays on your server and is never sent to the browser. | Keyword routing and rule-based autopilot still work. | | GEMINI API KEY | Regenerating wall art and textures with Nano Banana ≈ $0.034 per image . | Nothing: the generated images already ship in assets/ . | Other optional settings: DECISION MODEL , PORT , HOST , BLENDER PORT , LEVELDEZ ROOT see .env.example https://github.com/yeme-oss/LevelDez/blob/main/.env.example . Set them in .env or as real environment variables which take priority . Never commit .env . Security defaults. The server listens on 127.0.0.1 only. The raw Blender bridge /api/blender , which can run arbitrary Python inside a connected Blender is disabled unless you set LEVELDEZ ALLOW RAW BLENDER=1 . | Add rooms | + Room pick a type , the Add adjoining room button, or Generate layout for a whole floor plan. | | Place furniture | Click an item in the left palette searchable, grouped by pack , then click inside a room. Wall, ceiling and tabletop items snap to the right surface. | | Edit | Click a prop to select it: drag the gizmo to move or rotate snaps to 5 cm / 15° , or edit numbers in Inspect . Rooms have name, size, height, theme, and doors/windows you can add or remove. | | Shortcuts | Del delete · R rotate 45° · T top view · Esc deselect · Ctrl+Z / Ctrl+Y undo / redo | | View | Top , Ceiling show ceilings , Cutaway hides walls facing the camera , Fx cinematic rendering . | | Styles & packs | The style dropdown modern , scandi , rustic , industrial , luxe , gothic and the pack dropdown swap whole palettes and model sets. | | Start over | New gives a blank level; every change, including New, is undoable. | There are about 35 procedural furniture types that work with no assets at all, and any GLB dropped into assets/ automatically overrides or extends them see Asset packs asset-packs . microsoft/microsoft-decision-1 https://openrouter.ai/microsoft/microsoft-decision-1 is not a chat model . It reads a state and returns calibrated probabilities for fixed answer options. LevelDez uses three question types through OpenRouter's decisions endpoint, and batches many questions into one request: | Type | Returns | Used for | |---|---|---| | noul | probability of yes | "should the Add rug button be pressed?" | | choice | probability per option | style, room type, target room, wall/floor theme per room | | score | probability per level | rating how furnished a room feels empty → cluttered | php flowchart LR U You: Go box / Autopilot -- A Analyse each room<br/ fill %, lights, art, problems... A -- G{Cheap local gates} G -- D Decision-1<br/ batched yes/no panel D -- |p ≥ 0.5| B Press buttons<br/ furnish, compose, light, decorate B -- C Critic: score empty..cluttered C -- |not done| A C -- |done| E Export JSON + GLB - Go box: free text → one batched yes/no panel over every button → presses the approved ones in a sensible order → choice questions fill in the parameters style, room types, size, which room . - Autopilot: per room, local rules decide which questions are even worth asking; Decision-1 supplies the taste ; approved buttons are pressed; the critic decides when to stop, or to fill or declutter. - Vary surfaces: one choice per room type, size and neighbours with a penalty for repeats, so adjacent rooms get different finishes. - Ask: any yes/no question about the selected room, answered as a percentage. - No key or API down? Everything falls back to keyword routing and gate-only autopilot. Decision-1 presses the same buttons you can click yourself. | Group | Buttons | |---|---| | Layout | Furnish core · Compose room · Fill empty space · Declutter · Fix overlaps · Snap to walls · Face seating · Clear room | | Furnish | Add rug · Bedside tables · Style surfaces · Hang wall art · Gothic architecture · Add clutter · Add plants · Add lighting · Add curtains | | Structure | Add window · Add door · Resize room · Add adjoining room · Generate layout | | Style | Restyle · Apply asset pack · Vary surfaces · Mirror layout | - Generated floor plans. A main corridor, side corridors, big end halls, and rooms of varying size on both sides of each corridor. Doors line up through the double walls, windows appear only on exterior walls. 15 room types: living, bedroom, dining, kitchen, office, bathroom, hall, library, laboratory, crypt, chapel, corridor, classroom, dormitory, ritual. - Room themes. Wall finish damask, stone, brick, tiles, panelling… , floor marble checker, herringbone, cobble, plank… , wainscot, chair rail, crown moulding, trim colour and a mood light, picked per room type. - Compose room. 19 setup "kits" place cohesive clusters. Each is tried on up to 10 spots and the best score wins: fronts of cabinets, altars and hearths stay clear, walkways between doors stay open, setups spread out, wall pieces hug walls. - Architecture pass. Pillars, pilasters, window tracery and door surrounds scaled to each opening, ceiling vaults, cobwebs and floor sigils. - Lived-in layers. Decorated tabletops, wall art, curtains, rugs and floor clutter such as barrels, bone heaps and statues. - Lighting. A fixed pool of 18 point lights follows the camera focus: room mood lights plus candles, braziers and fires, with flicker. The light count never changes, so there are no shader recompiles. - Cinematic viewport Fx : MSAA, ground-truth ambient occlusion, bloom, split-tone grade with vignette and grain, drifting dust, soft shadows from the nearest lights. Props get a box-mapped detail map wood grain, stone, scratched iron, fabric… plus grime that darkens low on walls. This is a viewport shader: exported GLBs keep plain materials. Sub-folders of assets/ are packs . Drop in GLBs, optionally describe them in a manifest.json , and pick the pack in the header. GLBs without an entry are auto-registered, with placement and light guessed from the file name. GLBs download lazily, only for props a level actually uses, using the bounding boxes in the manifest. | Field | Meaning | |---|---| | as | Variant of a base type bed , wardrobe , rug … . The layout logic keeps working on the base type; the model is swapped in and fitted to its footprint. | | replaces | Pack-only type that stands in for a base type candelabra for floor lamp , arched mirror for mirror … . | | place / y | floor , wall mount height , ceiling , or surface sits on tables and shelves . | | tags | wall-hug , holds-decor , light , altar , curtain , decor … these drive the buttons . | | light , lightColor , lightY | Glow: adds a point light above the model. | | tint | Palette key that recolours materials named tint . | | Group | Built | Contents | |---|---|---| | Architecture | 87 | columns, pilasters, arch panels, window & door surrounds, ceiling vaults, cobwebs, wall weapons, skull mounts, chains, floor features, daises | | Furniture | 95 | bed, wardrobe, bookshelf, table, chair, throne, pew, desk, chest… variants; cabinets, lecterns, organs, bath and kitchen pieces | | Sacred & death | 65 | altars, sarcophagi, coffins, tombstones, crypt niches, statues, slabs, fonts, reliquaries, bone heaps | | Alchemy | 95 | cauldrons, benches, apparatus, 12 potions, 8 specimen jars, herbs, grimoires, scrolls, orbs, skulls, cages | | Lighting | 41 | candelabras, chandeliers, sconces, candle groups, lanterns, braziers, floating lights | | Study | 27 | book stacks, globes, orrery, astrolabe, telescope, hourglasses, map table | | Decor | 75 | urns, chalices, ravens, barrels, crates, rugs, banners, mirrors, clocks, masks, drapes | | Academy | 30 | student desks, podiums, slates, trophy cases, robe mannequins, racks, trunks | | Composition | 11 | fireplaces, wall-length bookcases, kneelers, grand candelabras | | Wall art | 50 | paintings, tapestries and stained glass, generated with Nano Banana | Plus a library of 49 textures walls, floors, wainscots and neutral detail maps , all generated and made seamless by script. tools/gothic/PLAN.md https://github.com/yeme-oss/LevelDez/blob/main/tools/gothic/PLAN.md is the full checklist of every item. Built from docs/make-a-pack-prompt - Scifi.md https://github.com/yeme-oss/LevelDez/blob/main/docs/make-a-pack-prompt%20-%20Scifi.md as a test of the make-a-pack prompt. Pick style: scifi it selects the pack and eight sci-fi room themes: hull white, bridge navy, neon noir, clean lab, cargo grey, hydroponic green, crew quarters, medbay . | Group | Built | Contents | |---|---|---| | Furniture variants of base types | 134 | beds, sofas, armchairs, chairs, tables, desks, storage, rugs, mirrors, lamps, plants, curtains, bath and kitchen pieces | | Signature props | 86 | cryo pods, bridge consoles, holotables, reactor cores, server racks, medbay, drones, vending machines, hydroponics, teleporters, android mannequins | | Lighting | 28 | neon signs, light strips, wall lights, beacons, holo lamps | | Wall | 34 | holo posters, screens, vents, shelves, pipe runs, signage, control panels | | Decor | 22 | datapads, holo cubes, mini bots, vials, ship models, cables | | Architecture | 20 | pillars, pilasters, door and window surrounds, ceiling details, floor decals | Generate or extend it with tools/scifi/load.py same resumable workflow as the gothic pack; PLAN.md https://github.com/yeme-oss/LevelDez/blob/main/assets/scifi/PLAN.md lists every item . Wall and floor textures reuse the neutral texture library, tinted per theme. You don't need to learn the toolchain. Any genre works cyberpunk noodle bar, Mediterranean villa, haunted motel, alien hive… : 1. Open docs/make-a-pack-prompt.md https://github.com/yeme-oss/LevelDez/blob/main/docs/make-a-pack-prompt.md and fill in the genre, a pack name and a size. 2. Paste it into an LLM agent that can run code and drive Blender for example Claude Code with a BlenderMCP server, started in this folder . 3. The agent plans the asset list, builds the GLBs, writes the manifest.json , then opens the editor and checks its own work. 4. Pick pack: <your name in the header and press Generate layout . The prompt is resumable it keeps a plan and a progress file , and it can add AI wall art if GEMINI API KEY is set. Want to see how the gothic pack was made? The recipes live in tools/gothic/ PLAN.md https://github.com/yeme-oss/LevelDez/blob/main/tools/gothic/PLAN.md lists every item , and python tools/gothic/gen art.py / gen textures.py regenerate its paintings and textures ≈ $0.034 per image via Nano Banana . - Export JSON: the full level, re-importable Import . Also visible and editable in the JSON tab. - Export GLB: every prop is a named node with its own meshes; shared materials are deduplicated. Both exports download and are copied to exports/ . - Open in Blender: the Blender tab can push the exported GLB into a running Blender. { "version": 1, "meta": { "name": "Nekro", "units": "m" }, "style": "gothic", "pack": "gothic", "rooms": { "id": "r1", "name": "Library 1", "type": "library", "x": 7.25, "z": 3.9, "w": 5.5, "d": 5.1, "h": 3.4, "theme": { "key": "scholar green", "wall": {...}, "floor": {...}, "wains": {...}, "mood": { "color": " ffb35a", "i": 0.55 } } } , "openings": { "id": "o1", "room": "r1", "wall": "N", "type": "door", "t": 0, "w": 0.95, "h": 2.1 } , "props": { "id": "p1", "type": "bed", "room": "r1", "x": 1.2, "z": -0.4, "y": 0, "rot": 90, "scale": 1, "variant": "gothic bed coffin bed" } } Rooms are axis-aligned rectangles in metres x , z = centre . rot is degrees about Y; host links a lamp or vase to the table it stands on. server.js zero-dependency Node server: static files, Decision-1 proxy, asset scan, exports public/ index.html app.js the editor three.js scene, UI, undo, export, Fx stack level.js level model, geometry, analysis, every button, layout generator, composition kits decision.js Decision-1 client: router, autopilot, critic, theme chooser catalog.js procedural furniture + lazy GLB loading, variants/replacements, detail shader themes.js surfaces.js room themes and textured wall/floor materials assets/ gothic/ ~600 GLBs + manifest.json + art/ source images textures/ wall, floor, wainscot and detail textures + manifest.json tools/ blender kit.py modelling kit for BlenderMCP gothic/ recipes, generator core, plan, Nano Banana scripts and prompts docs/screenshots/ images used in this README - Models are stylised bevelled primitives roughly 1–3k faces each , not sculpted meshes. The generators are built so better assets can be dropped in. - Rooms are axis-aligned rectangles; there are no L-shaped rooms or multiple floors yet. - Fx, detail shaders and mood lights are viewport only . Exported GLBs carry plain materials and no lights. - Decision-1 is an alpha-endpoint model; its request format may change. - Decals and story props stains, wax drips, cracks, open books, spilled potions - Decision-1 as an art director with measured composition checks blocked windows, focal point, crowding - Blender beauty renders and baked lighting for the exported GLB - Non-rectangular rooms, stairs and multiple floors - Built with three.js https://threejs.org and Blender https://www.blender.org driven through a BlenderMCP add-on . - Editing decisions powered by Microsoft Decision-1 via OpenRouter https://openrouter.ai . - AI-generated images: the 50 paintings and all textures were generated with Google's Nano Banana. Check Google's terms before redistributing them commercially. Public domain under the Unlicense https://github.com/yeme-oss/LevelDez/blob/main/LICENSE : use, modify and sell it for any purpose, no attribution needed. The Nano Banana images carry the caveat above. I'm on Patreon. I share insights about AI ventures, practical hands-on stuff. No fluff https://patreon.com/c/PierreIgorZarebski/ .