← Generated (OSM) demo · 🌍 Photoreal mode (Google 3D Tiles)

🏙️ Build Your City the Smart Way

A short guide for a dev who already spent a year on NYC.

First: building a city by hand for a year takes a lot of grit. Most people quit after a week. That skill and stubbornness are what ship games. This guide shows how the pros get the boring 90% of a city for free, so you can spend your time on the fun 10%.

Why studios generate cities

No studio places every building in NYC by hand. They generate the layout from rules (procedural) or from real map data (data-driven), then artists polish the places players actually look at. The demo you just played was made from OpenStreetMap footprints and heights in seconds, and the script can make any neighborhood.

Tools worth trying

OSM → Blender: Blosm addon imports real streets and buildings into Blender. Export to Unity or Unreal.
Real 3D cities in-engine: Cesium for Unreal / Cesium for Unity can stream Google Photorealistic 3D Tiles, which is basically all of Manhattan.
Unreal's free City Sample (from The Matrix Awakens): a full procedural city with traffic and crowds. Learn more.
ArcGIS CityEngine: rule-based city generation that films and games use.
Houdini: the industry tool for procedural content. There's a free Apprentice version.
Asset packs: search Fab (Epic's marketplace) for "New York" and "city" for modular buildings, props and storefronts.

How this demo gets its look

Real CC0 HDRI sky lighting and PBR textures from Poly Haven (brick, concrete, asphalt with normal and roughness maps), plus tone mapping, bloom, ambient occlusion and soft shadows, all running in the browser with three.js. The windows, billboards, cars and robots are generated by code. In Photoreal mode, the same game runs on Google's photogrammetry of real Manhattan, streamed with 3DTilesRendererJS. More free CC0 textures are on ambientCG.

Free sound & music

The demo's audio is all generated with code (Web Audio API), and the dispatcher voice is the browser's built-in speech. For real recordings, try Freesound.org (filter to CC0) or Kenney's free CC0 audio packs. Always check the license and credit creators.

How big games do it

Insomniac's Marvel's Spider-Man Manhattan is built from reusable modular tiles and building kits placed with tools, plus a set of hand-made landmarks. Here's their GDC talk on procedural lighting/city tech. Repetition is fine when the gameplay is good.

Scope strategy: the vertical slice

Pick 3–5 blocks, generated from OSM.
Make the core dispatch loop fun: call → route → arrive → score → next call.
Add one hero landmark and some polish. Playtest it with friends.
Then expand the map. A generator scales and a hand-built city doesn't.

Your year isn't wasted

Your hand-made models are perfect hero landmarks: drop them into a generated city where players will notice them. You also learned modeling, scale, texturing and optimization, which are the same skills pros use to polish generated cities. Now you get a faster pipeline to go with them. Go make it fun! 🚨