Introduction
This project explores the emergent geometric and spatial possibilities of a differential component system. Initial experiments with a variety of materials indicated that sanded .040” PETG was ideal for the project for reasons of availability, economy, and translucency. Additionally, the moderate flexibilty of the plastic proved to be a valuable material property. It should also be noted that the designers took significant conceptual inspiration from the process and method of pattern-cutting in the garment making industry. Thus, the final project expresses some of the flexible, sheet-like behavior of the product that inspired it while maintaining an aggregate rigidity that allows for structural integrity and spatial expression.
After defining a series of sub-local modules the designers determined the most effective way to harness the emergent behavior of those modules on a local level. The transition from a local to regional level yielded a variety of compelling possibilities; however, the system that the designers chose for further exploration is unique in its inability to produce recursion without significant manipulation. Put more plainly, the system developed by the designers is a spiraling system which will not spiral back upon itself.
Nevertheless, the system exhibits a number of compelling behaviors at the regional and global levels: the ability to channel airflow at both the macro and micro levels (which can be used to induce very effective passive cooling); the ability to affect particle accumulation (snow) and channel water; the ability to diffuse direct sunlight while maintaining a high degree of overall luminance; the ability to create different levels of visual porosity; the ability to harness the poetics of both colored and white light; and the ability to house vegetation as a green wall.
Process: Sub-local
The base module of this project is a 6”x15.875” rectangular sheet of .040” PETG; each upper edge of the rectangle has a convex cut in it, while the lower edge receives a concave cut. The “radius” of the cut varies in 1/2” increments between 3” and 5.” Once the pattern is cut the sheet is folded and secured with 1/2” machine screws. At the sub-local level, this creates a family of base modules (labeled A, B, C, D, and E, respectively) which exhibit a significant variety of end curvature.
Process: Local
Initial attempts at creating a local component did harness the geometric properties of each base module.
First, a horizontal joining logic was used. The problem with a this approach is that the emergent spiraling behavior of the base module occurs primarily around the vertical axis; joining modules horizontally (as rows) negates their tendency to create appreciable curvature. The second problem arose with the decision to use two additional screws when joining base modules together; this also seemed to negate any helicoidal behavior.
The inherent tendency of the modules to create helices of varying radii when attached vertically (i.e. columns rather than rows) became the primary rule for exploring emergent behavior. Indeed, as the individual modules of A, B, C, D and E definined the sub-local designation, so too do columns of A, B, C, D and E comprise the system at the local level. The most salient feature of the local level–the change in radii between A and E–is illustrated on the next page.
Process: Regional
Truly interesting emergent behaviors emerge when the assembly reaches the regional level. Initial observations about the failure of horizontal joinery were confirmed again at the regional scale with the creation of Flatland (above). However, all subsequent iterations produced notable emergent curvature. The synclastic curvature shown in the iteration Kissing Seat was most compelling to the designers and became the basic arrangement tested in further regional studies.
As is clear from the photos, all regional assemblies inherently create an end condition; the system’s inability to elongate in a traditional wall-like manner was a condition that the designers grappled with at length. However, this limitation must be balanced by what the system does do well: namely, creating a shelter.
Behavior: Air Movement
The topology of the columns that comprise The Kissing Seat suggest a potential to channel air in unique ways. While the overall geometry promotes cooling by way of establishing a negative pressure area inside the module’s entrance, it was speculated that the columns themselves would influence the specific direction of airflow on a small scale.
To test this, the designers attached small pieces of string to the outlet of each hole on The Kissing Seat. Using a household fan, three separate videos were made; the behavior of the strings supported the hypothesis: the columns manipulate the flow of air along their respective edges rather than simply allowing air to pass over the surface.
Air flow 1:
Air flow 2:
Air flow 3:
As seen in the diagrams, air passing over the exterior surface creates a low pressure zone, pulling air out from the high pressure zone underneath to create a cooling effect. Joints between columns channel air movement around the entire kissing seat.
Behavior: Particle Accumulation
During production a fortuitous snowstorm allowed the designers to examine the effects of particle accumulation on The Kissing Seat in a dynamic, real-world environment. The effects of the snowstorm illustrate the degree to which the design manipulates environmental airflow as suggested by the hypothetical analyses from both digital and analog tools. As indicated by the photographs, The Kissing Seat’s overall geometry has a significant effect on the way air moves around it, particularly at the base. Also notable is the formation of a drift inside the entrance to the kissing seat, which indicates an area of negative pressure. Finally, the study of snow on The Kissing Seat indicates an ability for the structure to literally disappear into the landscape, which can be architecturally exploited to great advantage.
Behavior: Light and Colored Light
While products born of an emergent process often exhibit the ability to provide a multitude of technical functions, the designers of The Kissing Seat assert that aesthetic and phenomenological functions are equally important. To assess The Kissing Seat’s aesthetic potential, colored (red) and white lights were projected onto the surface from a variety of angles and distances. In doing so, it was determined that light projected parallel or nearly parallel to the Kissing Seat’s surface had the greatest effect. Moreover, the sanded surface of the PETG allows for significant diffusion.
Behavior: Light, Shadow, and Porosity
As the photo montages illustrate, various versions of The Kissing Seat can easily be programmed as porous shelters in a variety of outdoor situations.
Perhaps more notable is The Kissing Seat’s ability to mitigate the views between interior and exterior. In the Porosity diagrams, the top photo is taken from inside The Kissing Seat. AutoCAD analysis of the red areas, which correspond to a view outside of the module, indicates a 9.5% porosity. Conversely, the lower diagram only indicates a 2.25% porosity. In implementing The Kissing Seat on a larger scale this information can be used to drive programming based on the need for privacy.
Behavior: Cascading Failure and Tensile Actuation
Upon construction of a 1.5:1 scale iteration of the structure, it became clear that the manufacturing limits had been surpassed. Buckling of the .040 PETG occurred in two locations (see photos this page) due to the increase in scale of the structure without a corresponding increase in material thickness. While a system of lock holes was implemented during fabrication, the material was simply not strong enough to support the additional weight.
However, an effort to capitalize on these shortcomings as yet another emergent behavior raised the question, “What if The Kissing Seat were a tensile structure rather than a compressive one?” When fully inverting the 1:1 Kissing Seat (photos on facing page) resulted in perfectly smooth curvature, the designers considered inversion of the 1.5:1 scale structure as well. However, because of spatial and structural limitations–as well as the difficulty of flipping an object that is 8’ tall and weighs nearly 200 pounds on its base–the designers chose to display The Kissing Seat on a base angled at 22 degrees. At this angle the columns utilizing lock holes act as a cantilever, stabilizing the entire unit.
Process: Parametric Variations
The designers of The Kissing Seat explored a number of parametric variations that could add performative or formal variety to the current iteration. For example, the perimeter geometry of the sub-local sheets can be altered to influence both air and water infiltration.
There are a variety of steps that can be taken to increase structural stability. While perhaps the most obvious solution to a lack of structural rigidity would be to fabricate the sub-local cells out of a more rigid material, the designers chose to focus their efforts on solving the
system “as built.” To that end, a series of 1/8” end ribs could be welded to the top edge of each sub-local module, increasing compressive resistance. Similarly, a 1/8” piece of acrylic could be added to the side of each module by attachment using existing connection holes. On a larger scale, an entire system of structural ribs could be designed.
One structural system that was implemented by the designers was the addition of locking holes to prevent hinge-type action at the joints. This modification, used on all columns of type A and E, proved to be a great aid to structural integrity.
Conclusions
In conclusion, it seems that the kissing seat offers significant potential for future exploration. While this experiment provides a very solid understanding of the basic behaviors of the system, future designers would be well advised to focus their explorations on 5 key points.
First, a comprehensive digital study (using a 3D scanner) could unlock the potential of varying the holes used to connect the sub-local modules. It stands to reason that if the holes used to join individual modules were varied in a deliberate and sensitive way recursion could be introduced into the system, eliminating the fixed edge condition currently present where The Kissing Seat meets the ground.
Second, the illustration of pure curvature in the inverted Kissing Seat indicates a whole realm of tensile possibilities. As one colleague remarked, “I can imagine this sort of thing continuing along the ceiling of my office in a linear pattern, totally getting rid of our need for boring cubicles. We could separate our spaces from above!” Indeed, the tendency of the kissing seat to “cantilever” itself into an actuated and effective space cannot be underestimated.
Third, the perimeter geometry of certain programmatically linked sub-local modules could be altered such that they have the ability to be permanently sealed along an edge. This edge sealing would create a cup, allowing them to function as mini-reservoirs that would encourage cooling through evapotranspiration. The cups would also more effectively support vegetation in a green wall.
Fourth, a different fabrication process might prove advantageous. For reasons of efficiency and economy the designers of The Kissing Seat chose to utilize a laser cutter with an 18”x32” bed for production. However, a laser cutter with a larger bed would allow production of sub-local modules with a larger scalar dimension. Alternatively, heat and/or vacuum forming out of a significantly thicker (1/8” or more) plastic material would provide necessary rigidity.
Finally, the inversion of The Kissing Seat into a tensile system is perhaps most compelling point. Indeed, luminaries such as Antonio Gaudi and Frei Otto have utilized gravity to smooth curvature and efficiently activate their structures; future designers would be wise to do the same.
