With over 230 new towers planned for London, the UK's capital could soon be left in the shade – literally. Though shade has always been a concern for architects and planners, London's dramatic increase in tall buildings will mean more darkness than before for those at street level. NBBJ has developed a custom algorithm that could mitigate this, and the firm used it to design a pair of concept towers that promise to reduce shadows on the ground by 60 percent, compared to similar-sized buildings.

NBBJ's custom computer algorithm takes such concerns as the angle of the sun, the best views, and the site's location into account, and the firm used this data to help create a pair of concept buildings slated for London's Greenwich that measure roughly 200 m (656 ft) tall and have 50 stories.

While not completely shadow-free, the two concept skyscrapers would offer a shadow reduction of 60 percent – and won't melt any cars, either – thus potentially making them more attractive to planners, developers, and anyone who spends significant amounts of time nearby.

So how does it work? "The algorithm design is based on the law of reflection," David Kosdruy, designer of the No Shade Tower project (which also includes James Pinkerton), and Digital Practice Leader at NBBJ, tells Gizmag. "Sun reflected from a straight façade provides an even distribution of light at just one point in time over a specific area. From a spherical façade it results in a concentration of light in one point. Both these results are not desirable for a no shade tower.

"Our façade on the other hand has varying angles of façade panels that distribute light over a certain area at multiple times during the day. Based on that principle we developed a Computational Design Script, using Grasshopper, a genetic algorithm and in house python libraries that enabled us to find the optimal angles necessary to reduce the shadow in between the two towers at a desired time during the day.

"The information about the angles got fed back to a parametric geometry model that generates the building envelope. In the further refinement of the façade we also took more parameters into the optimization to maximize the views of the river from the upper floors for example."

NBBJ's project could be implemented outside of London too. Design Director Christian Coop tells Gizmag that the algorithm is just as useful for producing a tall tower in Morocco as it is to producing a relatively small one in Alaska. "The idea can be used everywhere and the tower's forms would change to suit … always unique," says Coop. "We can also modify the shadow reduction throughout the year (in hot countries less in summer more in winter etc.)"

The project also highlights the increased role that computers have to play in architecture (a topic explored in greater detail in our Creative AI architecture feature). However, the designers tell us that we're nowhere near the point where a real designer could be replaced by an algorithm, and the system is better considered as another tool for architects and designers.

"Luckily we are not in a time yet in which computer algorithms can replace designers," added Kosdruy. "The 'click here to solve everything' approach does not work yet. But definitely the role of the designer changes when designing with algorithms. The way how we design the inputs and the algorithm determines the quality of the output. Because of that it is very important for a designer to ask the right questions and program the algorithm accordingly to get a meaningful result. Designing the right constraints and interpreting the output in the right way is often an iterative process in which the algorithm-literate designer has a creative role."

The No Shadow Tower remains a concept at present, but with London and other major cities increasing in density, the issue of shadows looks set to take on even greater importance.

Source: NBBJ

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