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.

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A pdf of my presentation can be viewed by following the link below.  I have video of the script being used, but it is too big to post here. Regrets.

Minerich Digital Boat Presentation

p3_proposal_mary jo minerich_#001

Hull Design Grasshopper Script

For the final project I propose to design a small watercraft, similar to the ones I described in my p1 post.

Typologically it could be described as the design of an archetypical form with parametrically controlled variations.  More specifically, I first propose to use the capability of the programs we have been learning to adapt the generic form common to these types of boats to specific performance criteria.  For example, the grasshopper script listed above provides a means to adjust the buoyancy, “aerodynamics”, and waterline as functions of the geometry of the boat’s hull.  

Beyond this, I want to investigate the capacity of the structural or functional elements to provide further design/aesthetic value.  By utilizing a translucent fabric for the exterior skin, the structure has the capacity to create patterns visible from the outside.  

 Ming mentioned that in addition to utilizing grasshopper to design the geometry, variations could be generated and assessed using Galapagos.  

In terms of fabrication, I am thinking that the structure could be laser cut and assembled by slotting the pieces together, similar to the “waffle” type structures we have seen.  I think this could offer an advantage over typical boat construction and detailing, in which metal fasteners can risk corrosion or worse, puncturing the skin.  On the other hand, if it is possible to attempt full-scale fabrication, the bed size of the laser cutter and the cost of cutting may have a strong impact on which designs are feasible.

The template for the fabric skin could be pulled from the geometry of the structure and plotted, although it would probably have to be cut and sewn manually.

p2_Mary Jo Minerich_#001

frank miller lumber_1763

Inspired by Art Nouveau Wallpapers


(more wall papers at  http://thetextileblog.blogspot.com/2010/05/harry-napper-wallpapers.html)
I began with a single non-square grid with a roughly 2:3 ratio between the width and height. I then moved and scaled some of the vertices to get the grid to look more like arrows or triangles in some places. After that I began a series of extrusions and scales that resulted in the two more simple patterns (they are actually almost the same, but one has the extrusion width set larger to make the filagree smaller). I plan to set them at 90 degrees to one another. The final one comes from the previous patterns, with an extra poke face and extrusion.  Finally I “smoothed” them all to make them more organic.  Final screens shown below.

p1_Mary Jo Minerich_#001

Coming into this class, I realized how very little I knew about the possible uses of parametric design. After a bit of research, it seemed to me that the primary uses related to design occur at either very large scales (urban planning, landform) or very small scales (furniture and product designs), and in the case of architecture, frequently operate independently from other building systems (for example a parametrically designed rainscreen with organic forms that doesn’t need to address the gridded window system behind it or outdoor pavilions that don’t need to maintain a thermal barrier, or various lighting and display systems that inhabit and change the interior profile of an otherwise typical space without requiring a change in the thinking of the electrical or plumbing etc). Foreign Office Architect’s Yokohama Port Terminal comes to mind as a great architectural counter example where the form of the building actually follows desired circulation paths through space, and a combination of software modeling and craftsmanship allowed the wood cladding to be used in a more plastic way. (Interior corridor shown below) As a result, I am very interested in exploring the potential of these programs to have a significant impact on the performance, function and constructability of an object. Maybe its because the weather has been lovely, or because I’ve been learning about wood, but I have been thinking a lot about boats lately. Although I was able to find little or no information about the use of parametric design in small boat building, it seems that this might be a really interesting area for ideas and practices related to craft, structure, and function to be guided by a relational and iterative way of thinking about the design. For the purposes of this case study I am limiting my comments to “skin light frame” style boats, as these are within the realm of what a person can actually craft and because they seem particularly appropriate for this type of design because they consist of two precisely related elements, the structure and the skin, which are responsible for the performance of the boat. In the image below, you can see the most basic configuration of this kind of boat’s “skeletal” structure and its fitted skin. This design concept is based on a boat called the umiak, created by the Inuit people who live along the Alaskan and Canadian coast. I think that parametric design could help to design the structure of a boat like this for more specific weight, durability, or speed requirements, and could allow for more atypical forms, even a structure that could have ornamental qualities. Furthermore, because the structure is skeletal, it can be created as a series of interconnected component parts specifically designed to manage a pattern of structural loading. As a related example, in the video below a group of students is able to create a vaulted ceiling structure from a number of smaller pieces of laser cut plywood. Arch Structure created from small parts from YouTube This is also frequently employed in furniture design, so that a light frame structure of wood can take on a more organic shapes and still carry significant loads. Chair by Matthias Pliessni. Not only does the boat itself have a skin, but a sail for the boat is also a kind of “skin” that relates to the environment around it. I was able to find a video that uses some cheesy editing to “explain” how they use parametric design software to optimize the design of the sails. Despite this, it is very interesting to see what factors affect the design of a good sail, and how the sails are sewn from two dimensional fabric, anticipating their ideal three dimensional shape when activated by the wind. On the design side, I am thinking that parametric design would allow more interesting shapes and sizes of sail that could still fulfill their necessary function.

North Sails design video