KunalSiyag/gridfall

Watch the trailer · Website · Download v0.1.0 · Write-up on DEV
GridFall is a 3D SimCity-style city builder made with Godot 4.7 (Forward+), Blender, GMI Cloud inference and ACE-Step 1.5 audio. You don't build the city. Five autonomous AI mayors do, each running on a different GMI Cloud model. Every other layer of the city also has a GMI model behind it. You watch, inspect and intervene.
GridFall was built with Factory's Droid coding agent, which wrote the Godot code, the Blender asset pipeline and the tests. Every mayor, resident and city agent runs on GMI Cloud inference.
## The AI city
| Role | Model | What it does |
| Mayor Argon-4 (NW Civic Campus) | google/gemini-4-argon | Utility-first planner |
| Mayor DeepSeek-V4 (NE Tech Corridor) | deepseek-ai/DeepSeek-V4-Flash-0731 | Systems engineer |
| Mayor Kimi-K3 (Central Plaza) | moonshotai/kimi-k3 | Coalition builder |
| Mayor Qwen-3.8 (SW Eco Quarter) | Qwen/Qwen3.8-Max | Fiscal pragmatist |
| Mayor Grok-4.5 (SE Boomtown) | x-ai/grok-4.5 | Growth maximalist |
| Citizen Voices | MiniMaxAI/MiniMax-M3 | Residents react to their real tile data |
| GridFall Gazette | XiaomiMiMo/MiMo-V2.6-Flash | Daily newspaper and editorial |
| Council Speaker | openai/gpt-6-luna | Rules on ordinances the mayors propose and vote on |
| Chaos Director | deepseek-ai/DeepSeek-V4-Pro | Picks disasters that test real weaknesses |
| Grid Operator | google/gemini-3.8-flash | Sets the power load-shedding priority |
| Street Inspector | MiniMaxAI/MiniMax-M3 | Click any tile; whoever is standing there tells you what's wrong |
Once per in-game day, each mayor gets an ASCII map of its district, district and city stats, open lots, its open construction sites, land it can annex, yesterday's results, other mayors' posts, letters from its residents, the Gazette headline, open proposals and any player decree. It replies with JSON: a private thought, a public post, a mood, up to 7 actions (road, zone, build, bulldoze, taxes, emergency, grant, annex), an ordinance proposal and votes. The simulation checks every action and rejects invalid ones with a reason.
## Simulation
World: the founding city is 32×32 tiles (x,y 0..31) with a river, forests and five districts, inside a 192×192 frontier (x,y -80..111) of unclaimed woods, lakes and the river. Mayors annex unclaimed 16×16 plots that border their district; each plot costs a little more than the last ($1500, then +$400). Surveyors map land up to two plots beyond claimed territory; the frontier past that sits under a haze that lifts as the city grows. Per-tick systems and most view passes only touch claimed land plus a 3-tile margin, trees are drawn in chunks that switch to low-poly stand-ins far from the camera, so the bigger world costs little. Saves from the old 96×96 world load into the same place in the bigger one.
Zoning: R/C/I demand and density growth (levels 1–3). Growth depends on road access, power, water, land value and taxes.
Road grades: a road order can be a paved street ($10 a tile), a gravel road ($6), a dirt track ($3) or a grass trail ($1). Rougher roads cost less to keep up but are slower to drive, and a lot grows only as dense as the best road within 2 tiles allows (gravel 2, dirt and trail 1). A better grade ordered over a rougher road resurfaces it. Mayors short of money open land with cheap grades and pave tracks with built lots beside them once they are rich. On foot a track has no curbs, sidewalks, lamps or signals: cars slow down, give way to the right at a crossroads and do not park there, more of the traffic is cyclists, and residents whose trip runs mostly on tracks are twice as likely to bike. Flag roadgrades.