The photolepidote project pursues spatial arrangement and light modulation through a structural tiling system that is parametrically defined by two sub-systems: the tiles and their distribution on the attachment surface. The tiles are geometrically varied and related to relevant manufacturing strategies. Their particular performance capacity is dependent on their geometric articulation, on the angle to an input source that results from a specific layering of the tiles, and on their materiality and surface finishing. These last two criteria define the thermal mass and reflectivity of the tile surface.

The determinant factors for tile assemblies lies within a parametric model of the individual tile, with the variables set as tile width, length, thickness, outline of top and bottom surface, top and bottom profile and, most importantly, location of the attachment point. The second sub-system is the attachment surface onto which the tiles are fixed. Its purpose is to keep the tiles in place while allowing surface curvature to emerge from the articulation of each tile and the way it touches neighbouring tiles. The attachment surface is therefore made from initially elastic material – a flat surface formed of strips — that accommodates the emergent surface curvature as the system is assembled tile by tile. The length of the strips and their assembly template are informed by the desired tile distribution patterns and resultant surface curvature. Since the articulation and distribution of the tiles determines the surface curvature of an overall assembly, different distribution strategies were tested. With the attachment point being normal to the attachment surface, and the tiles overlapping, bending is induced into the lattice und curvature is achieved across the surface. In other words, it is the articulation and layering of the tiles that induces curvature in the lattice through bending and torsion, instead of pre-shaping the lattice. Tiles are therefore always placed on the outside of the curved surface: when a transition between convex and concave curvature is required the tiles shift from one side of the attachment surface to the other at the point of inflection.

The orientation of each tile and the gaps between the tiles determine the range of effect of direct, indirect or diffuse light. Calibrating the overall effect for spatial regions within the envelope, for instance the finely nuanced pattern of direct light or shadow cast within the space was one of the primary tasks in the development of the system and its environmental performance analysis; calibrating the thermal mass of each tile in relation to its exposure was another. For this purpose it was important to establish a parametric logic in an associative modelling environment that adjusts geometric variables in relation to orientation and exposure. Further research might examine, for instance, the thickness of the tile in relation to its material characteristics and exposure to thermal input, so as to achieve the desired thermal performance.

AA Diploma Unit 4 (Michael Hensel, Achim Menges)
Alexia Petridis, Architectural Association, London, 2004-05