Ghost Town

No more ghost towns.

Type an address in Blender and get the city around it: buildings, terrain, roads, sidewalks, water, parks, trees and lot lines, built from open data as clean geometry you can take into Revit or any BIM tool.

1140 Dundas St W at Ossington, Toronto, 150 m radius: find the address, build, and switch the ground between colours by kind and the aerial photo. The build is shortened here. Data: City of Toronto and Natural Resources Canada (see Data and credits).

Ghost Town is a free, open-source extension for Blender 5.2 and later. It is at an early stage (version 0.3): Toronto is covered in depth, and the rest of the world gets buildings only.

What you get

Where the site is	Buildings	Terrain	Ground, trees, lot lines	Address search
City of Toronto	City 3D Massing model, newest edition: stepped parts with measured heights	NRCan elevation, 2 m grid	Roads, sidewalks, parking, rail, water, parks, trees, parcels	Yes
Elsewhere in Canada	OpenStreetMap	NRCan elevation where available	Plain ground only	Not yet (type coordinates)
Rest of the world	OpenStreetMap	Flat	Plain ground only	Not yet (type coordinates)

Each build makes one collection, Context · <site>:

• Buildings: one object per building. Each tier is a closed prism standing on the terrain. Buildings that cross the circle come in whole. In Toronto, parts of the City's model that touch or overlap form one building object, and where parts overlap the taller one wins. On a main street a whole block face can become one object; Separate › By Loose Parts splits it in Blender. Elsewhere in Ontario, with LiDAR roofs ticked, each building also gets two roofs measured from the province's LiDAR: a fitted roof of a few planar faces, which a build shows, and the sampled LiDAR surface. You can switch between them and the flat top. Buildings from the City of Toronto's model keep its massing, the same flat-topped blocks the City publishes as SketchUp and AutoCAD files.
• Ground: one draped surface per kind (road, sidewalk, parking, rail, water, green, plain ground). The pieces share their edges, so there are no cracks or overlaps. Water lies flat at its shoreline.
• Trees: a trunk and a low-poly crown each, sized from the City's tree heights, merged into one object.
• Parcels: lot lines draped 15 cm above the ground.
• Aerial photo (Toronto): the City's newest aerial photo of the site, kept inside the .blend file, for the ground and low roofs. See Use.
• Materials: one per kind, named Context - Building, Context - Road, and so on. A building whose height had to be guessed is orange (Context - Building (height guessed)).
• Location: a Context origin empty at 0,0,0 holding the latitude, longitude, ground elevation above sea level, the origin's survey grid coordinates and the data credits.

Everything is in metres, with x east, y north, the address at the origin and z = 0 at its ground level.

235 Queens Quay W, Toronto, 300 m radius, built in about 8 seconds.

320 Bay St, Toronto, 300 m radius.

Install

Ghost Town needs Blender 5.2 or later on macOS (Apple silicon or Intel), Windows x64 or Linux x64. It bundles the one library it needs (shapely), so there is nothing to pip install.

1. Download the zip for your computer from the latest release:

   Your computer	File
   macOS, Apple silicon	ghosttown-<version>-macos_arm64.zip
   macOS, Intel	ghosttown-<version>-macos_x64.zip
   Windows	ghosttown-<version>-windows_x64.zip
   Linux	ghosttown-<version>-linux_x64.zip

2. In Blender, go to Edit › Preferences › Get Extensions › ⌄ › Install from Disk… and pick the zip.

3. Go to Edit › Preferences › System › Network and turn on Allow Online Access.

Building it yourself

git clone https://github.com/winterweken/GhostTown.git
cd GhostTown
tools/build.sh

tools/build.sh downloads the shapely wheels from PyPI and writes one zip per platform into dist/. It expects Blender at /Applications/Blender.app; on other systems, set BLENDER to your Blender executable first. Install the zip as above.

Use

1. In the 3D View, open the sidebar (N) and the Ghost Town tab.
2. Location: type a Toronto address such as 320 Bay St and press the search button beside it. If several addresses match, pick one. Anywhere else, type latitude, longitude, for example 51.5074, -0.1278.
3. Site name (optional) names the collection. A found address fills it in.
4. Radius: 150, 300, 500 or 1000 m.
5. Fetch: tick Aerial photo (on by default) to fetch the City of Toronto's newest aerial photo of the site with the build. It is kept inside the .blend file. Tick LiDAR roofs (slower) in Ontario to fetch the province's LiDAR and give buildings outside the City of Toronto's 3D Massing model measured roofs. It is a large download, and the province's server can take a minute to answer the first request.
6. Press Build Context. A 300 m site takes about 10 seconds and a 1000 m site about 20. With LiDAR roofs ticked a build takes a few minutes more, because the province's server is slow to send the LiDAR (a 300 m site in Hamilton took about 4 minutes). Cancel or Esc stops it, and Ctrl+Z removes a finished build in one step.

Building the same site again replaces what Ghost Town made and keeps anything you added, including your own objects and collections inside the context collection.

The Site section under the panel shows one site at a time; pick it at the top. It lists the site's survey point, and, when the site has an aerial photo:

• Ground: Colours | Photo shows the photo on the ground, or the colours by kind. Shows in Material Preview, or Solid view with Color: Texture.
• Roofs: Plain | Photo puts the photo on the roofs of buildings up to a height you set (20 m to start). Taller buildings lean in the photo, so their roof texture would be offset.
• Save Site Photo… writes the photo and a world file, for an underlay in Revit or CAD.

When the site has LiDAR roofs:

• Roof shapes: Flat | Fitted | LiDAR switches every building between its flat-topped prism, its fitted roof and its LiDAR roof. Fitted shows after a build: a house gets the flat, shed, gable or hip roof that best explains the LiDAR, its planes running out to the walls, and a larger building gets stepped tiers at its measured roof levels, at least a storey apart. Every fitted roof is a closed solid. Sites built before fitted roofs existed show Flat | LiDAR.
• Roof detail simplifies LiDAR roofs, from 100 % down to 5 %, without moving walls or eaves.
• For Revit shows the site's triangle count. Past the budget in Preferences (500,000 to start) it says: Heavy for Revit: use Fitted or Flat roofs, or lower Roof detail, before exporting.

Wismer, Markham, 150 m radius with LiDAR roofs: the houses switch between flat tops, the LiDAR surface and fitted roofs, and the triangle count for Revit follows. The LiDAR download, a few minutes, is cut here. Data: OpenStreetMap, Natural Resources Canada and Geospatial Ontario.

Switching never downloads anything again, and each site in a file keeps its own choices.

Taking it into Revit

Ghost Town does not export. It keeps the geometry friendly to exporters and to Revit instead: metres, closed building solids, outlines cleaned of edges under 3 mm, and stable material names.

• OBJ: set Up Axis: Z (Blender's default is Y).
• FBX: tick Loose Edges if you want the parcel lines.
• In Revit, import origin to origin. The material names become the layers or materials you control under Object Styles › Imported Objects.
• Before exporting, set the site's Ground to Colours and Roofs to Plain, so every piece keeps its Context - … material. While the photo shows, exporters see the photo material on those faces instead.
• Fitted roofs export as closed solids of a few faces each: the lightest measured roofs, and the ones to take into Revit.
• LiDAR roofs export as meshes, which Revit imports as DirectShapes: heavier than prisms. Exporters apply Roof detail (modifiers are applied by default), so keep the site under the panel's budget, or use Fitted or Flat roofs.
• To use the aerial photo in Revit, Save Site Photo…, then in a site plan use Insert › Image, set the image's width to the width Ghost Town reports (twice the radius, in metres), and centre it on the origin.
• Survey point. The model stays at the origin, which is the site's latitude and longitude at ground level. After a build, the panel shows where that origin sits on the survey grid, and its copy button puts the values on the clipboard. The grid is the City's own in Toronto (NAD83(CSRS) / MTM zone 10, EPSG:2952) and the site's UTM zone elsewhere. The same values are on the Context origin empty as survey_easting_m, survey_northing_m, survey_elevation_m and survey_grid_angle_deg.
• To set Revit's survey point, go to Manage › Coordinates › Specify Coordinates at Point, pick the model's origin, and enter the northing, easting and elevation. Ghost Town's +y is true north, while Revit's true north is the survey grid's north; enter the grid angle as the Angle from Project North to True North, East or West as the panel says.
• The elevation is the height above sea level of z = 0 (ground_at_centre_m). Latitude and longitude are used as given, which matches the City's data; positions from OpenStreetMap or a phone can be 1–2 m off. The survey point lines up context, not a legal survey.

Data and credits

Ghost Town downloads open data when you build. If you publish anything made with it, credit the sources you used. The panel lists them after every build.

Source	Used for	Credit
City of Toronto open data	Buildings (3D Massing, newest yearly edition), aerial photo, ground, trees, parcels, addresses, city boundary	Contains information licensed under the Open Government Licence – Toronto
Natural Resources Canada (HRDEM)	Terrain	Contains information licensed under the Open Government Licence – Canada
Geospatial Ontario (lidar-derived surface and terrain models)	LiDAR roofs in Ontario	Contains information licensed under the Open Government Licence – Ontario
OpenStreetMap	Buildings outside Toronto	© OpenStreetMap contributors (ODbL)

More detail is in CREDITS.md.

Accuracy. This is context for early design, massing and presentation, not survey data. Building heights are derived from aerial data, some are guessed, and lot lines are approximate. Check anything you rely on against a survey.

Privacy. Ghost Town contacts only gis.toronto.ca and the City's open data portal (ckan0.cf.opendata.inter.prod-toronto.ca), datacube.services.geo.ca and overpass-api.de, and, only with LiDAR roofs ticked, ws.geoservices.lrc.gov.on.ca, and only when you press the search button or Build Context. It sends what the query needs (the address you search for, or the location and radius you build) and nothing else. Answers are cached on your computer for 30 days. The City's 3D Massing model is downloaded once per yearly edition (81 MB, about 300 MB unpacked in the cache folder) and kept until a newer edition comes out. It lives in the cache folder (Preferences › Cache folder; by default the extension's own folder); deleting its toronto_massing folder is safe, and the next Toronto build downloads it again. With Aerial photo ticked, the photo comes from gis.toronto.ca with the build and is kept inside the .blend file, which adds up to about 5 MB. LiDAR answers (10–30 MB a site) are cached like the rest, and LiDAR roofs are kept inside the .blend file, about 20 to 30 MB for a dense 300 m site (less with Compress, in File › Save As or Preferences › Save & Load).

Ghost Town is an independent project. It is not affiliated with or endorsed by the City of Toronto, Natural Resources Canada, the Province of Ontario or OpenStreetMap.

Known limits

• Outside Toronto there are no roads, trees or parcels yet, and outside Canada the ground is flat.
• Buildings are flat-topped prisms unless they have measured roofs (Ontario, outside the City of Toronto's 3D Massing model). LiDAR roofs carry no roof planes, just measured points.
• Fitted roofs give a house one roof for its whole outline, so an L-shaped house whose wings have their own ridges gets the main roof's planes, and a house under thick canopy may keep a flat top at its measured height. Larger buildings become tiers at least 3 m apart, so their sloped or curved roofs become steps.
• LiDAR roofs on house-sized buildings (up to 400 m² and 20 m tall) are trimmed to their own typical height plus 3 m, which removes a tree crown over part of the roof; trees over most of a roof still raise it.
• A building newer than the province's LiDAR survey keeps its flat top in Fitted and LiDAR modes, and one surveyed while under construction can show a partly built roof.
• Bridges and elevated rail are draped onto the ground.
• A stream is flat at one level along its length instead of following its valley.
• Rebuilding a site resets colours you changed on the Context - … materials.

How it works

The Blender side only draws. All downloading and geometry work happens in a separate process running Blender's own Python, so the interface stays responsive, Cancel is immediate, and a problem there cannot take Blender down.

sidebar panel ─▶ request.json ─▶ fetcher process ─▶ context.json ─▶ collections, meshes, materials
                                  (ghosttown_fetch)

• ghosttown/ghosttown_fetch/ is plain Python (numpy and shapely, no Blender). Each data source is one module in sources/, which is where new cities and layers go.
• ghosttown/*.py is the extension: panel, operators, the process runner and the scene builder.

Roadmap

• Worldwide address search.
• OpenStreetMap roads, green space, water and trees outside Toronto.
• Terrain outside Canada.
• A site outline: cut your site out of the ground and mark its buildings and parcel.

Development

uv sync                    # Python 3.13 with numpy and shapely, matching Blender 5.2
uv run pytest              # fetcher tests; they run offline against recorded answers
/Applications/Blender.app/Contents/MacOS/Blender --background --factory-startup \
  --python-exit-code 1 --python tests/blender/run.py     # Blender-side tests
tools/build.sh             # per-platform packages in dist/
tools/smoke_installed.sh "320 Bay St" 300   # macOS: install into a throwaway profile, build a live site

Issues and pull requests are welcome. New data sources are the most useful contribution: a source is one module that turns a public dataset into polygons, points or lines.

Licence

GPL-3.0-or-later. See LICENSE. The data Ghost Town downloads keeps its own licence, listed under Data and credits.

The Ghost Town name and logo are © winterweken and are not covered by the GPL. That includes the files in media/brand and the icon in ghosttown/icons/. You may use them to refer to this project; please ask before using them for a modified version or another product.