Monthly Archives: September 2011

Traditional Craft / Digital Craft: Some Thoughts on Form, Material, and Assembly

“…a saw cannot be generated from wood, nor does this lie in the power of the [art], for it cannot make a saw of wool or wood. If then it is possible to make the same thing from different matter, clearly the art, ie. the moving principle is the same”  Aristotle, Metaphysics 1044a28   

According to Aristotle, a given form can only be created from certain materials if it is to fulfill all of its definitive functions—as seems obvious, a saw made from wool fails to cut even the softest material. On the other hand, he argues, the same art or “form giver” can produce the same effects in different materials. A “saw” can be made from metal or stone, or today, even a laser. As I was thinking about the ways that form suggests a corresponding material and fabrication process manually, I began to wonder what this might entail for the functional and aesthetic qualities of the finished product, that was both digitally designed and fabricated. During my initial survey of types of designed fabrications for Project1, I began to notice that while the possibilities for three dimensional form creation were seemingly unlimited, the available technology for fabrication seemed to dictate a specific set of strategies for their production governed by questions of material, scale, time, mass, and sometimes cost. Lisa Iwamoto’s Digital Fabrications: Materials and Techniques helped to clarify the connection between the machines used in fabrication and the final assembled product. I became interested in the laser cutter as a particularly versatile machine capable of cutting materials of various scales and sizes into pieces that could be folded, interlocked, or stacked to create three dimensional irregular forms, all for relatively little cost. Using the laser cutter to produce a layered pattern in project 2 encouraged me to consider as well the potential for ornament that the laser cutter makes possible, which due to its complexity or size would be difficult if not impossible to produce by hand. I wondered if this unique capacity of the laser cutter to develop ornament could be put to use in conjunction with the functional elements of a form. For the final project, I began looking for a form determined by simple functional requirements so that I could understand the relationships and re-define them using the parameters of the digital tools I was learning. The discovery of skin on frame boats seemed to present the perfect challenge, not only because of its formal and functional simplicity, but also because it fits into a long tradition of hand-crafted construction techniques that confers aesthetic value as well. My original concept then for the project was to utilize Grasshopper and Rhino to create the boat’s form, but then to consider how the laser cutter could be used to construct it faster, out of more economical material, with a structure that exhibited a new capacity for expressive ornamentation.

Traditional Craft                                                                                                                             To create skin on frame boat the traditional craftsman will begin with a process called “lofting” to determine the boats’ geometry. This process breaks a boat down into three types of views, called the profile (elevation), half breadth (half of a plan view), and stations (cross-sections perpendicular to the profile and related to a center line). Each view is defined by a series of points that are drawn at full scale on the floor. Thin wood pieces called “battens” are tacked from point to point to generate the necessary curves.  

Lofting Diagram from The Boatbuilder’s Apprentice by Greg Rossel.

The craft-person then uses these outlines to construct the necessary formwork on which steam-bent pieces of green wood can be shaped. Steam bending allows the builder to take advantage of wood’s superior strength in the direction of its grain for the entire surface of the boat. The first pieces will correspond to the stations (cross-sections) which will then be connected steam-bent ribs running along the length of the boat. Finally, the boat is wrapped in Dacron Polyester fabric, which shrinks when heat is applied. The Dacron provides a translucent absorptive network on which the epoxy coating creates a durable and waterproof finish. While this creates a light durable and beautiful boat, there are significant disadvantages for many people due to the level of skill required to build it, and the difficulty and cost involved in sourcing high quality green wood for the ribs. Even for the talented craftsperson well familiar with the materials, the process of lofting does not allow significant opportunities to explore the ornamental or aesthetic potential of the frame itself.

Digital Craft                                                                                                                                  The digital design of the boat ended up being remarkably similar to the process of lofting. Points were used to create cross sections that were altered along the length of the boat. The sections were then connected using a “loft” component in Grasshopper.

The main difference between the traditional method and the digital method lies in the flexibility and analytical potential of the digital method. The designer can easily create multiple hull shapes and evaluate them simultaneously from all directions in the virtual environment. With a little more time, it would be entirely possible to include performance analysis as a part of the script to better understand the functional impact of formal alterations. The design process could even be automated to some degree by designating specific standards as rules in a program such as Galapagos. The most interesting challenge to traditional methods occurs at the level of fabrication. To fabricate the form of the boat at full scale, marine grade plywood can be cut into a number of slotted sections that will interlock with one another, creating a thin yet rigid hull. This has both advantages and disadvantages when compared with the tradition of individually steam bent pieces. Specifically, while the traditionally crafted hull will be somewhat lighter and stronger, the cost, skill and the amount of time required for fabrication will be greatly reduced for the digitally crafted boat. Because plywood is composed of many thin layers of wood with alternating grain directions, the material is equally strong in any direction. This means that the material is not restricted in the direction it can be oriented, opening unique potentials for ornament in the arrangement of the slotted sections.

Assessments and Adaptations                                                                                                       To test this project I developed a ¼ scale model out of 1/16” chipboard that I consider to have been moderately successful in fulfilling the stated goals. First, while the boat scrip I created in grasshopper was mostly successful, I believe that this effort dominated the amount of time spent on the project as a whole and left little time for the direct investigation of the ornamental potential of the structure. The appearance of the final structure was largely determined by the use of a downloaded “waffle” script, that was not exactly correlated to the nature of this type of hollowed out form. Specifically, the waffle script assumed a thick solid three dimensional form that would be sectioned evenly throughout, at fairly large intervals. This resulted in too few sectional pieces that could not intersect with enough frequency to be self-stabilizing. From the perspective of ornamentation, this prevented me from having much control over the patterns created by the intersecting pieces. While they are generally making an interesting design that would be seen through the transparent skin of the boat, a closer look betrays some very ungraceful intersections between the parts. Adapting the waffle script to allow for uneven spacing of the sectional pieces, and to make the intervals smaller would have greatly improved the durability, ease of assembly and appearance of the assembled boat.


Works Cited

Iwamoto, Lisa. Digital Fabrications: Architectural and Material Techniques. New York: Princeton Architectural Press,2009. Print.

Rossel, Greg. The Boatbuilder’s Apprentice. Camden: International Marine, 2007. Print.