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3D city model: real cities from map data, game cities from building sets
Get a 3D city model from OpenStreetMap or official city data, or build a game city from modular buildings. Scale, detail and performance tips.
2 min read
Quick answer
How do I get a 3D city model?
For a real city, use map data. OpenStreetMap building footprints with heights can be turned into 3D blocks with Blender add-ons, and many cities publish official 3D models. For a fictional city in a game, build a small set of modular buildings in one style and repeat them along a street layout.
Real city or invented city?
That one question splits everything.
A real city: start from data
- OpenStreetMap has building footprints for much of the world, and many buildings have height or level tags. Blender add-ons and other tools extrude those into 3D blocks. Good for massing, planning visualisation and backgrounds. Not detailed facades.
- Official city models. Many cities and national mapping agencies publish free 3D building models, often in CityGML. Search your city's open-data portal.
- Streamed photoreal tiles, such as Google's photorealistic 3D tiles, bring real cities into some engines and viewers under the provider's terms.
Respect each source's licence. OpenStreetMap data requires attribution.
An invented city for a game
Real-time cities are built from modules, not modelled one building at a time:
- Pick a style and a scale. Decide door height, floor height and texture density once, so every building matches.
- Make a small set of buildings. Eight to fifteen types go a long way: a few houses, shops, a tall block, a landmark or two.
- Lay out the streets and place the buildings, rotating and recolouring to hide the repeats.
- Make one or two landmarks properly. They're what people remember.
AI generation fits step 2. Sketch or describe each building in the same style and generate them as a set. Vi3W exports them retopologised as GLB or FBX. Consistent art style helps them look like one place, and 3D house models covers single buildings.
Performance: the real work
A city is hundreds of buildings on screen at once:
- Level of detail. Far buildings swap to simpler meshes. Level of detail.
- Shared materials and texture atlases, so buildings batch together.
- Low poly for mobile. Low-poly assets for mobile games.
- Simple collision, a box per building.
Prototype first
Block out the streets with grey cubes, test that the city plays well, then swap in final buildings. Free modular assets for prototyping gets you started.
Try it
Generate your city's building set in Vi3W from one sketch per building.
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