3D reconstruction of Amatrice. A shared process
For us, create the model of Amatrice in 3D was another step to save the memory of a city that in this moment doesn’t exist. It was a shared process thanks to the GIS documentation that is present in the web posted by people after the earthquake of the 24th of August. Furthermore, all the internet data describe the whole valley that connect Arquata del Tronto, Accumoli e Amatrice.
The first problem was model the landscape without lose too much time. The starting data came from the site - http://earthexplorer.usgs.gov/ - Here I got a GeoTiff image which accurately described mountains and valleys with a grayscale coloured map. By using an algorithm programmed with Grasshopper we have been able to modelling the shape of the terrain.
Regarding to the buildings, our goal was an expressive representation with the accuracy of 1:500 scaled model, taking care the typical elements which characterize the model of a town, of this town: towers, belltowers, Elevations along the main streets and the religious building.
The hard work would be drawn the plan view of the whole town but with openStreetMap (https://www.openstreetmap.org/) we jumped all the 2D modelling. Also, all the boundaries of the buildings collect information about height of the building before the sisma. Still, thanks to the scripting It was possible to sort the amount of the data and use it to extrude the planar closed curves and create volumes.
We moved the volumes from the plan to the correct height on the surface of the mountain. Then It was the time of the roofs. We thought that drawing the roofs was an important step to represent an historic centre. So we divided the different typology of covers in two: the gabled and hipped roof. The skyline of Amatrice 3D was the result of the sum of this two covers. We solved the problem of modeling with an algorithm that started from few signs drawn on a orthophoto of the 2014.
We moved the volumes from the plan to the correct height on the surface of the mountain. Then It was the time of the roofs. We thought that drawing the roofs was an important step to represent an historic centre. So we divided the different typology of covers in two: the gabled and hipped roof. The skyline of Amatrice 3D was the result of the sum of this two covers. We solved the problem of modeling with an algorithm that started from few signs drawn on a orthophoto of the 2014.
We developed the elevation along the main street on the plan, so it was easy to draw the holes of windows and doors, but also pilasters and string courses. The method used to orient the drawing was to invert the previous transformation and with the oriented curves we made the volumes to add or subtract elements to the elevation.
We were more careful to the religious buildings and important monuments adding more details to them.
At the end of the modelling it was the time of prepare the geometry for fabrication. The historic centre was divided in squares 125 x 125 mm to fit the 3D print basin, and the suburbs was nested into the same space. The surface of the terrain was became a solid and the boundary of the building was subtracted to the terrain. During this operation we kept in mind the tolerance coming from the difference of the material used for the terrain (polystyrene) and the buildings (plastic).
For milling we used 200 x 70 cm slice with the thickness of 10 cm, so I had to cut the terrain in pieces and create a void inside. At the end we obtained an amazing model 200 x 400 cm big!!!!
