**Parametric Perforation - 2009**

The idea of Parametric Perforation was developed as a Stone Cladding Pattern. The aim was to clad a façade with tiles of stone on a structural grid, regularity or irregularity of which would define the porosity and translucency of the facade.

A regular pattern would make an opaque façade, while an irregular pattern makes a translucent facade with the perforation through which light is directed into the building. A smooth transition between the two can make an elegant stone pattern which can potentially be linked to the necessity of the program behind it.

The stones in this exercise are all assumed to be of squares with four equal sides sitting on a simple structural grid. The size of each tile is defined by the size of the grid. Each tile is just as big as the smallest of the four cells of the grid around it. If the grid is even and the four cells are of equal sizes, then the tiles also will be regular and all in the same size which results in full coverage of the façade; any change in the distance between the elements of the grid will cause a porous façade.

A normal square grid consists of two sets of parallel lines. The unevenness in the distances can happen only in one of the two sets, or in both. If one set is regular and the other one not, they will produce linear openings; if both sets are irregular, they make cellular openings.

The Other Possibility could be using an overlay of two grids, each defining a different layer of stones with a different colour or texture. The two could work together in a way that changes in the size of one would change the size of the other.

The following diagrams show some samples of this technique used to generate a variety of sometimes radically different patterns.