During my last holiday I got to spend a few days in Barcelona. Barcelona is full of amazing modern architecture from some of the world’s most famous architects. The building that most captures the public’s imagination is undoubtedly the Sagrada Familia. The last time I saw the Sagrada Familia was in 1999, back then only the exterior façade of the had been built and the interior a building site, so it was interesting comparing my old photos to see how its changed.

The Sagrada Familia when I last saw it in 1999


The interior of the Sagrada Familia as it is today


New Zealand Architect Mary Burry worked on the Sagrada Familia for several years.
I have been to a few of his lectures on the building which he gave some insights into Gaudi’s methods and the techniques modern architects are using to complete the project.
The curved surfaces in the design are not free hand curves, but precisely defined geometry. Gaudi often used ruled surfaces and developable surfaces to define these curves. (A developable surface is a curved surface that can be flattened into a flat sheet without stretching it.  While a ruled surface is curved surface where every point on the surface has a straight line going through it.) By using these surfaces Gaudi could precisely describe to the stone masons how to make the curved faces of the stone.

Below are examples of a ruled surfaces Although the sufaces are curved, every point on the surface has a straight line going through it. These types of surfaces are used thoughout the builing. The shape on the left is known as a hyperbolic paprabolid and the right is a hyperboloid of revolution.


Gaudi also used an interesting method to create the form of the columns. He started with a star shaped profile with rounded points at the base of the column. If we imagine 2 of these profiles slowly rotating in opposite directions as they travel up the column. The plan shape of the column changes as these profiles travel upwards. The green shape opposite shows how the plan shape of the column changes. About halfway up the column the number of profiles increases from 4 and then to 8. I believe Gaudi idea was this would create a tree like form that is rounder at the top and looks as though it spreads out to form roots and the base.