What Site Context Generator does

Define a circular area around a site, pull buildings / roads / trees / water, and export the context geometry to Rhino or DXF — ready to use as backdrop for your design.

Source:

Public mapping data

Output:

.3dm / .dxf

Modes:

2D · 3D

How it works

Everything is built in your browser from public mapping data — the extraction, the solids and the CAD file all happen locally, and the model is never uploaded anywhere. The honest caveat is upstream: the geometry is only as complete as what volunteers have mapped at your site.

• Buildings, roads, water and landuse queried per layer from OpenStreetMap via Overpass, so an unticked layer is never fetched.
• Requests spread across several public Overpass mirrors, because their health and speed vary through the day.
• Address search resolved through Nominatim.
• Terrain from open elevation tiles, stitched and meshed to the extraction radius.
• Building heights from the OSM height or building:levels tags; buildings carrying neither are extruded to a stated default rather than silently guessed per building.
• Roads given real width from their classification and tags rather than drawn as centrelines.
• .3dm written client-side with rhino3dm, layered so the context arrives in Rhino already organised.

How to use it

1. Search a location. Type an address or drag the map to centre the extraction.
2. Set the radius. Up to 2 km for 3D extraction, 4 km for 2D plans.
3. Choose features. Toggle buildings, roads, water, trees, terrain on/off.
4. Pick 2D or 3D. 3D includes terrain mesh; 2D flattens to plan geometry.
5. Generate & download. Preview the extraction, then download .3dm or .dxf.

Best used for

• Getting a site model into Rhino in minutes instead of an afternoon of tracing.
• Backdrop and context massing for shadow, wind, view and daylight studies.
• Early massing work where the neighbours matter more than their detail.
• Competition and feasibility work on sites you cannot visit.

Not a substitute for

• Survey-grade context, boundary lines or anything dimensional you will build to.
• Planning submissions without a measured survey behind them.
• Confirming that something is not there — an empty area usually means unmapped.

Known limits

• OpenStreetMap coverage is volunteer-made and uneven: excellent in some cities, sparse a few streets away, and occasionally years out of date.
• Most buildings carry no height tag, so a large share of any extraction is extruded to a default rather than measured.
• Buildings are flat-topped extrusions of their footprint — no roof form, no setbacks, no projections.
• Terrain is open elevation data at tile resolution, which smooths real ground and can float or bury buildings on steep sites.
• Public Overpass mirrors are rate-limited; a sparse result can be a truncated query rather than an empty site, so re-run before believing it.

Read the full Site Context Generator guide →