Interactive Architecture

iA #2-episode publishes Rotterdam 2008

By: Kas Oosterhuis

To control the shape and the look of the design, a NURBS surface was created. NURBS is an acronym for Non-Uniform Rational Bezier Splines, a container for a number of polynomial algorithms. Its use is widespread in the design and character animation industry. In architecture the use of these techniques involves a genuine paradigm shift away from the use of two-dimensional plans and sections. Simply put, one cannot build a double-curved surface using plans and sections, because every plan and every section is different at different section planes. The logical reaction is to use the NURBS surface as the plan by having it govern the integrity of the construction. Expanding on the conventional paradigm of a construction grid, ONL mapped a triangular grid with the internal integrity of an icosahedron on the NURBS surface. The icosahedron system was chosen for a number of reasons, the main reason is that it is a closed system, like the design.

In architecture, irregular surfaces can be bothersome to build and strategies to build them are often based on layers. For example, a crude approximation of a shape is constructed in steel and with a number of cladding layers, this crude approximation can be smoothed. Creating a low-res construction for a high-res shape obviously lacks control over the shape and it is costly for it needs multiple layers of construction, secondary construction and cladding. A more precise method is the creation of customized molds for every segment of the building, however, this concentrates the effort primarily on the cladding; a construction is still needed, making the whole very expensive. Another strategy is projecting one or more regular grids over the shape, like one would slice a loaf of bread. Although this approach results in perfectly manageable constructive ribs that can be manufactured relatively easily, it is only viable for tube-like constructions. Projection is inherently flawed for closed irregular surfaces because in its projection vector, it introduces a form of anisotropy in its construction. This means the building construction favours a certain direction over others.

The line is the trajectory of moving points, or in other words, its witness. The line has developed from the movement ‘indeed by the destruction of the highest in itself enclosed peace of the point. Here the jump from the static to the dynamic has been made.’ The trajectory of the line is influenced by a number of internal and external force a working upon the line during the time of the tracing process. Internally, the body/arm puts on constraints and willpower to the trajectory. External forces are, for example, the tool that the line is drawn with or the medium (paper, digital space) that the line is drawn upon. A line can be defined as an infinite sequence of points.