We all know that buildings don't always turn out like the renderings. Last-minute changes and real-life materials can all cause discrepancies between the vision and reality of a project. In our weekly Flash Forward Friday feature, we take a look at how different projects stack up.

An early rendering shows the tower without its signature struts and antenna, image via Arata Isozaki & Associates

Milan's ongoing mixed-use CityLife development includes three skyscrapers as the centrepiece of its master plan. Developed by Generali Group, the project brings together Arata Isozaki & Associates, Studio Daniel Libeskind, and Zaha Hadid Architects to create three disparate highrises. So far, the Arata Isozaki-designed Allianz Tower, also known as Il Dritto (the straight one), is the only tower in the trio to mark completion; Il Curvo and Lo Storto are currently under construction.

A revised rendering of the project, without its eventual antenna, image via Arata Isozaki & Associates

The 50-storey skyscraper rises to an architectural apex of 209 metres, but the addition of a broadcast antenna brings its total height to 242 metres. Designed in collaboration with Andrea Maffei Architects, the second-tallest building in Italy holds office space within an envelope composed of eight billowing modules of six storeys each. Four golden-coloured buttresses provide extra stability to the tower, and although more traditional techniques could have accomplished the same objective, the support struts intentionally emphasize the mechanics of the building. 

The final rendering of the Allianz Tower (right), image via Arata Isozaki & Associates

But that wasn't always the case. Earlier renderings of the project showed the slender tower employing nine convex components instead of the eventually built eight, while the rooftop antenna and golden struts were entirely absent. A later rendering would then incorporate these external elements — without their signature golden hue — and change the dynamic of the tower by eliminating one module, largely matching what the finished project looked like.

Allianz Tower completed, image by Alessandra Chemollo via CTBUH

A final rendering portrayed the gold sheen of the struts and the soaring antenna. The only major difference from the ultimate rendering and the completed development was the addition of the blue-lettered Allianz branding on the top, giving the building its corporate flair.

Allianz Tower, image by Flickr user Luca Galli via Creative Commons