ArcGIS delivers city models as STL: Workflow for 3D-printable buildings from GIS data

Printed city models are a popular project, but obtaining suitable data is often a tedious process. In a blog post, Esri describes a process for converting building data from the ArcGIS ecosystem into printable 3D models. According to Esri, the workflow was developed by Paul Gibbs. The starting point is the City Download Portal, an open-source browser tool from the ArcGIS Maps SDK for JavaScript.

The portal loads a web scene and works with two queries. One determines the surface height and uses it to generate the ground mesh. The second loads the buildings from a 3D object feature layer. Depending on the scene’s permissions, authentication may be required to access it. The export is initially in GLB, the binary form of glTF. Gibbs has expanded the portal so that it converts GLB directly into STL in the browser. Optionally, the tool adds a base extrusion for a flat print surface.

To make the buildings available as a 3D object feature layer, the tutorial guides you through data preparation in ArcGIS Pro. Overture Maps Explorer serves as the source. There, buildings and, if necessary, “Building Part” are activated, an area is selected, and the visible data is downloaded as GeoJSON. “Buildings” and “building-part” are relevant because they contain elevation attributes. In ArcGIS Pro, “JSON To Features” converts the GeoJSON files into polygon features. If the layers are not visible, the elevation settings are set to absolute height. Extrusion is then performed using the “height” field, unit meters.

After extrusion, buildings and building parts partially overlap. Gibbs selects intersecting buildings using “Select by Location” and deletes these features. “Merge” then combines both data sets. From the extruded polygons, “Layer 3D to Feature Class” generates multipatch objects as closed 3D models. With “Add 3D Formats to Multipatch,” .glb and .gltf are added so that the feature class serves as a 3D object feature layer.

For distribution, publish as a web layer in ArcGIS Pro, including the activated export option. After the cache is built, the scene is opened in the browser, the item ID is transferred to the forked City Download Portal, and the desired section is selected using a bounding box. The download provides GLB or STL, optionally with terrain base.