A scale model of the Gdańsk Crane: drone survey, photogrammetry and 3D printing

The Crane on the Motława is one of Gdańsk's best-known buildings, and you cannot measure it with a tape. Two drone flights, 830 photos and photogrammetry in RealityCapture gave a georeferenced, textured 3D model. From it came a printable solid and a 156 mm PLA scale model, printed in 7 h 51 min on a single FDM printer. Drone flights: Marcel Łuczak.

IE-032 · FIG.01 · Render from the 3D model (Blender). The print-ready model and a flight diagram: the drone circles the building at three heights, every photo sees it from a different side. An illustrative route, not a flight log.

From flight to scale model

01
Airspace
checked before take-off
Gdańsk airport zones over the river; flight allowed up to 100 m.
02
Flight
2 flights, several heights
Large photo overlap, every wall and roof from many sides.
03
Photos
830 shots
Raw material for the reconstruction, about 29 MB per photo.
04
Photogrammetry
RealityCapture, WGS 84
Camera positions, a point cloud and a textured mesh at true scale.
05
Point cloud
roof tiles from points
Geometry that exists in no CAD file, measured from photos.
06
Print prep
solid, base, supports
A 90 x 156 x 138 mm STL, tree supports under the eaves.
07
Scale model
PLA, 7 h 51 min
Towers, roofs and superstructure read clearly at 156 mm.

Problem

A scale model of an existing building starts from geometry nobody has in CAD. A historic building is brick, roof tiles, irregular towers and a timber superstructure, and drawings, if they exist, do not match today's state. The roof cannot be photographed from the ground, and the Motława sits inside the airspace zones of Gdańsk airport. A photo-based model is millions of triangles with holes wherever the camera did not look, while a printer needs a closed solid in millimetres, with a base and sensible supports.

Outcome

Two flights produced a true-scale 3D model of the Crane and a PLA scale model where the towers, roofs, timber superstructure and quay all read clearly. The same model can be printed at another scale, in resin or in several parts to assemble, without flying again. The same route works for any building a drone can safely reach: models for developers, museums and councils, souvenirs, documenting the state of a monument.

01Airspace. Before take-off, the zones are checked in the DroneTower app: over the Crane there are Gdańsk airport zones (CTR EPGD) and two DRA zones; the flight is allowed up to 100 m above ground, no mission filing needed.
02Flights. Two flights, 16 April and 12 May 2025: the drone circles the building at several heights and shoots with large overlap, so every piece of wall and roof is seen from many sides. The second flight fills in the views missing after the first.
03Photogrammetry. 830 photos go into RealityCapture. The software finds the position of every shot, computes a point cloud and from it a textured mesh in WGS 84, i.e. at true scale and position.
04Mesh cleanup. Simplification to 1 million triangles, cutting away the surroundings, closing the solids and adding a base with a piece of the quay. The result is one print-ready STL: 90 x 156 x 138 mm, about 118k triangles.
05Printing. Bambu Lab A1 mini, PLA, 0.20 mm layers, tree supports under the eaves and the timber superstructure. 102 g of material, 7 h 51 min of printing. A resin version was prepared in parallel for when finer detail is needed.