Nobody pays them for it, but they decide to 'work' for free modeling buildings for Google Earth . Thus, thanks to the selfless collaboration of thousands of people, this application that allows flying over the world from a bird's-eye view is nourished by three-dimensional buildings. The most 3D city in the world is Madrid, where there are more than 5,000 buildings that are lifted off the map.
Of them, a hundred have been modeled by David Alonso, a 33-year-old graphic designer who began to shape emblematic buildings by "hobby". "I was curious to see how the programs provided by Google used to design buildings," he tells RTVE.es. "After that I continued to be a hobby and also because people interested in these issues are known".
Among the buildings in Madrid that have become almost 'palpable' in Google Earth are many emblematic, such as the Royal Palace, the Cybele, the Magic Box, the Palace Hotel or the Telefonica building on Gran Vía.
It has also given three-dimensional life to the famous windmills in Castilla-La Mancha and "a palace in Astorga", the town of his father.
Google makes two geo-modeling programs available to Internet users: Google SketchUpand Google Building Maker .
Building Maker is the easiest to use. As David explains, "the most common thing is for people to search their home in Google Earth and the next step is to give it shape in 3D."
It's the closest thing to a mix between Google Maps and a bucket of building blocks. Basically, it consists of choosing a building and building a model of it, based on the photos and forms offered by Google.
Google SketchUp "is more advanced and allows more complex things". The designer explains that with Building Maker in about 15 minutes anyone can shape their house in 3D , but with this program for example you could not make the Cibeles.
Of the 100 buildings that have been built in this virtual world, the one that most resisted him was the Royal Palace, which has an area of 135,000 m². "It was the most complicated because of its complex architecture, its arches, its roofs and because it has many details."
It was also a challenge for Cybele "for the human form of the statue and the lions" because the advanced program of Google also has its limitations.
To make the 3D copy of the Royal Palace, the first step was to inspect the land. "I went there and took pictures surrounding the building to capture all the faces," he explains.
Then with the SketchUp "the background photos are placed and the program provides three-dimensional blocks, with that the volumes are generated".
To finish the model "the photos that were taken on the surface of the object are projected and with a program of photo retouching the imperfections are cleaned".
The last step is to send the creation to Google, which checks it to see if it fits the size and reality . "If it meets all the requirements, it appears in the 3D layer of Google Earth."
Google does not remunerate David, nor the other users who collaborate voluntarily enriching the program. "I would not mind if they paid me", he jokes, although indirectly, thanks to this hobby he got a reward: to find work in a graphic design project.
Now he would like to be able to travel and do "more buildings outside of Madrid", although he has one pending in the capital: the Calatrava obelisk . "I still do not know very well how I could translate his movement, but I want to do it."