Site Context Generator

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

Built from open mapping data. The ArchiTool site engine assembles buildings, water, green and roads for the area you choose; the 3D model and the CAD file are then made in your browser, and your own model is never uploaded. The honest caveat is upstream: the geometry is only as complete as what has been mapped at your site.

• Buildings (with building parts and courtyards), water and green from Overture Maps, which combines OpenStreetMap with footprints from other open sources where OSM is thin.
• Roads and trees from OpenStreetMap via Overpass, per layer, so an unticked layer is never fetched; if the site engine is unavailable, every layer comes from OpenStreetMap instead.
• Address search resolved through Nominatim.
• Terrain from open elevation tiles, stitched and meshed to the extraction radius.
• Building heights from recorded height or floor counts; a building with neither takes the typical height of nearby recorded buildings, labelled as estimated, or a stated default where none are nearby.
• Recorded roof shapes (gabled, hipped, pyramidal, single-slope, dome) built on top of the walls.
• Rivers and lakes kept whole with their islands and set level, with the terrain lowered under them; bridges span what they cross.
• 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.
• Many buildings have no recorded height; those are estimated from nearby buildings or set to a default, and labelled so in the export.
• Roof shapes appear only where they are recorded; other buildings are flat-topped, and balconies and projections are not modelled.
• River and lake beds are not measured: the ground under water is a placeholder just below the surface.
• 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 →