A city print and a terrain print look like the same job and are almost opposite. Terrain wants a wide frame and careful height. A city wants a tight frame and no height at all — because the interesting vertical thing is the buildings, and they come from a completely different source.
Go small. Smaller than that
The single most common mistake is framing the whole city. At 20 km across, individual buildings are a fraction of a millimetre and merge into grey mush.
| Width | What you get at 150 mm |
|---|---|
| 1–2 km | A neighbourhood. Individual buildings clearly separate. The best-looking option. |
| 3–4 km | A recognisable city centre. Manhattan below Central Park fits here. |
| 5–8 km | Street pattern reads, individual buildings do not. Still good with roads raised. |
| 10 km + | Mush. Print land cover and roads instead, and leave the buildings off. |
At 3 km wide on a 150 mm plate, one millimetre of print is twenty metres of city. A terraced house is about six metres across — a third of a millimetre. That is the resolution you are working at, and it is why the frame matters more than anything else.
Building heights are real, where they exist
Heights come from OpenStreetMap, where somebody has entered them. In central London, Manhattan, Paris and most large European cities, coverage is good. In smaller towns it is patchy, and buildings without a height get a sensible default rather than being dropped.
So the skyline of a well-mapped city is genuinely its skyline: the Shard really is taller than everything near it. In a small town you are printing footprints with a uniform extrusion, which still looks good but is not survey data. Worth knowing before you claim otherwise.
Ignore the terrain
Most cities are flat enough that terrain contributes nothing, and any exaggeration you add fights the buildings — the ground starts to tilt and the towers lean with it. Leave the terrain at 1× and let the buildings do the work.
The exceptions are worth seeking out. San Francisco, Lisbon, Edinburgh, Wellington, Shimla: cities where the hills are the point. There, raise the exaggeration to about 2× and the model explains why the streets go where they go.
Printing buildings
Buildings are the one part of a map model with genuine vertical walls and sharp corners, so the settings differ from terrain:
- 0.12–0.16 mm layers. Finer than terrain needs. Corners and window-less flat faces show every defect.
- Cooling at full. Small footprints stacked tall need it or they slump.
- Slow down small perimeters. A 0.4 mm building wall printed fast comes out wobbly.
- Still no supports. Buildings are prisms rising from the ground, not overhangs.
- Base 3–4 mm, and a raised frame around the edge helps a city plate enormously — it turns a fragment of map into a deliberate object.
The combination that works best
Roads raised slightly, buildings at real heights, water inlaid, and built-up land cover filling the gaps between them. Four colours if you have them, or print the road and water parts separately and inlay them by hand.
What you get is the thing people actually want from a city model: they find their street, then their building, then they go quiet. Manhattan at 3 km is framed here if you want to see the effect before committing to your own town.