Antoni Gaudí’s breathtaking architectural forms are often mistaken for pure organic fantasy, but they are actually rigid applications of structural physics. To design the soaring interior vaults of the Sagrada Família and the Church of Colònia Güell, Gaudí devised a revolutionary method using funicular, or inverted catenary, models. A catenary curve is the natural shape a flexible chain or string assumes when hanging under its own weight, subjected purely to tensile stress.
Gaudí realized that if you flip a catenary curve completely upside down, the tension forces transform perfectly into pure compressive forces. By tying intricate networks of string from the ceiling and hanging small canvas bags filled with lead shot to simulate the weights of prospective stone walls and towers, Gaudí created three-dimensional physical gravity computers. The hanging strings naturally adjusted their angles to find the optimal structural equilibrium.
Once a hanging model settled into balance, Gaudí took photographs of the structure, turned the photographs upside down, and had his draftsmen draw the building plans directly over the inverted images. This pure compression geometry allowed Gaudí to eliminate the heavy, dark flying buttresses characteristic of traditional Gothic cathedrals, replacing them with slender, branching tree-like columns that efficiently channel structural weight down to the foundations while filling the interior with radiant sunlight.