Subdivided Columns - Fabrication of Initial Prototype
A full-scale, 2.7-meter high variant of the columns was fabricated as a layered model using 1mm sheet. Each sheet was individually cut using a laser cutter. Sheets are stacked and held together by poles that run through a common core.
The calculation of the cutting path for each sheet takes place in several steps. First, the six million faces of the 3D model are intersected with a plane representing the sheet. This step generates individual line segments that are tested for self-intersection and subsequently combined to form polygons. Next, a polygon-in-polygon test deletes interior polygons. A series of filters then ensures that convex polygons with peninsulas maintain a mininimum isthmus width. In a final step, an interior offset is calculated with the aim of hollowing out the slice to reduce weight.
While the mean diameter of the column is 50cm, the circumference as measured by the cutting path can reach up to 8 meters due to jaggedness and frequent reversals of curvature. The initial prototype uses 1mm grey board. Tests using ABS, wood, as well as metal are under way.
Fabrication of the initial column prototype was carried out at ETH's CAAD group using the university's RapLab. Fabrication assistance was provided by Manuela Koller, Thomas Raoseta, and Edyta Augustinowicz.
(Link to prototype images)