3D digitising historical buildings is not the exclusive area of experts with expensive equipment anymore. Using a consumer drone and special software, anyone can now digitase buildings in their town or district, as I have proved with this experiment, carried out in fall 2015.
The idea is to create 3D scans of buildings using consumer-grade camera drones and a piece of software called PhotoScan, which allows the user to create a 3D model from a series of photos taken from different perspectives. Using aerial photos made by a drone, big objects like buildings can now be 3D digitised too.
For this experiment I selected a historical windmill in the vicinity of The Hague, the Netherlands, built in 1672. Together with 2 other windmills, this windmill was used to create the Nieuwe Driemanspolder, a piece of land that is now part of Leidschendam.
In this case I worked with a DJI Phantom 3 Professional quadcopter, and selected the so-called ‘Point of Interest’ intelligent flight mode, which allows the drone to automatically circle around an object, keeping the camera pointed at the center. This video nicely demonstrates this POI mode.
Using the time lapse photography mode of the camera, I created a series of photos of the windmill. Every 5 seconds a photo was made, during the whole 360 degree flight path around the windmill. In thumbnail view, this collection of images looks like the screenshot below:
The series of images was subsequently tranferred to PhotoScan. This piece of software is able to reconstruct a 3D wireframe, based on the information that is captured in the photos. This step is represented by the screenshot below. (The blue area above the windmill represents all the photos and their location in 3D space.)
After that a photo-realistic texture (also derived from the photo series) can be applied, so that the wireframe resembles the real world building:
In the interactive SketchFab player, you can rotate the 3D model as you wish and see the windmill from different angles: https://sketchfab.com/models/c92474e20c66459bb9188ad7925c3065
The experiment shows that it is perfectly feasible to 3D digitise buildings and large areas by (amateur) drone pilots from all over the world. The technology can be used for many purposes, such as documenting local heritage sites in 3D, creating small scale models of buildings via 3D printing, and for gaming and virtual reality purposes, showing buildings and objects from the real world. The technology can also be used for archeological purposes, mapping large pieces of terrain and digging sites in 3D.
The only limitation is the fact that operating a drone above urban areas is illegal in many countries. Also buildings and areas near airports can’t be photographed by drones, as it is forbidden to operate a drone near airports.
The total costs of equipment and software used for this experiment is about € 1.500, but even cheaper drones could be used, so that the total sum would be less than 1000 euros. The 3D models can be hosted on platforms such as Sketchfab, which allow for creative commons licenses and downloadable 3D objects. Also Wikimedia Commons will probably support 3D objects soon, making this technology even more interesting for community-based 3D digitising efforts.