Digital Curvature —Experimental Study of Digital Wood Fabrication

Climate change, global warming, excessive carbon emission, and pollution are issues we human beings need to solve to not only survive but also continue our civilization and create a better future for our decedents. Among all the environmental issues, traditional construction methods contribute a majority of the problems. Figuring out sustainable methods of construction is an impending task. Thinking about all the unsustainable resources the traditional construction consumes, and all the carbon it emits, going back to using wood as the major construction material seems to be optimistic, especially when the wood is coupled with new technology to explore its full construction potential. Although we need to strategically plant and harvest wood construction materials to keep this method sustainable, we also need to invent methods of treating and assembling wood components to most efficiently put them into construction.

However, when we look closer, we can see that the construction timber typically produced in this industrial era can only choose a certain range of tree species, and because of the need to produce standard-sized timber, many log materials will be wasted. It can be said that the trees themselves are very different in variety, size, color, and growth. However, the production of wood products is always pursuing standardization and simplification, and removing any "heterogeneous" that does not meet the standards. This goes against the unlimited potential that nature empowers with trees — not only is the production efficiency of wood lower, but also the characteristics of each tree are completely obliterated. With the advancement of modern technology, is it possible to develop wood in a more ingenious way, and can the potential of each tree be explored more with 3D simulation and robot arms precision cutting? If these technologies can be combined, the freedom of designing wooden buildings or wood materials will be completely opened, and new architectural forms will emerge.

In order to make the best use of the robot arm, the limited research funds were used to purchase a second-hand German brand KUKA robot arm that previously served on automobile production lines. However, when the robot arm is in operation, it will generate a lot of inertia, so the first step is to design and build a solid and safe working platform. In order not to damage the workshop itself, we chose to cut and weld a well-shaped steel frame, and fix it on the concrete floor with screws; then poured eight cement counterweights to prevent it from shaking; finally, A safety cage system was also designed, which can be used to stop dangerous operations immediately and avoid close contact between anyone and the robot arm during operation.

After doing this, it is necessary to study how to connect cutting saws to the robot arm, so that it can cut out tracks that are impossible in a normal sense. Attaching a chainsaw is relatively simple. Because the chainsaw is kind of nimble, it can go deep in any direction. However, the sawtooth itself is thick, so it cannot cut curves and would generate a certain amount of material loss. Considering the short comes of a chain saw, it is better to study how to connect the band saw because a band saw can cut very delicate curves with very little loss. Although the volume of a band saw is relatively large, it can still move flexibly through the wood material. Therefore, a structural system was designed for the chain saw alone, and various steel components were welded and fixed together with screws. After several tests, it was found that the band saw is still a light load for the robot arm.

After finishing the research on the robot, the next step is to study the tree itself. As can be seen in the diagram, even the most unsuitable trees have more than half of the materials that can be used to make building components, through 3D scanning and 3D modeling, not to mention there are various species. At the same time, there are many ways to cut the trunk: you can cut out curves on a more standard trunk; you can cut out a two-dimensional curved surface by twisting the cutting path; you can also cut out many layers along the growth direction of the trunk, etc. Different from the traditional design concept, this method requires the designer to explore the characteristics of the material at the beginning and continue working towards the known design vision until a consensus is reached, so as to generate an absolutely unique design.

Among these cutting methods, slicing along the growth direction of the logs can save the most material and fully respect the characteristics of the tree. After 3D scanning and modeling of a small branch, we imagined what effect the branch would have if it were cut into fourteen pieces. Through 3D simulation, we found that the horizontal and vertical angles can be adjusted to form various shapes. It is conceivable that if different woods from different cuts of different trunks are spliced together, the possibilities are endless. Therefore, multiple groups of simulations were carried out with small branches to explore the possibility of splicing and combining. It can be found that because of the characteristics of the curved surfaces, these wooden curvy surfaces can enclose horizontally and vertically sufficiently, and would form an architectural pattern that blurs the facade and roof, which is actually more in line with the organic characteristics of trees.

When the 3D simulation was done, we went to the forest to find logs. Because the workshop was close to the forest, there were a lot of usable materials laying on the ground, which prevented material waste from the source. After finding an "unconventional" log that is straight at all, and performing detailed 3D scanning, we restored this log with extremely high precision in 3D software. In order to fix the log in space so that it could remain still under the operation of the robot arm, three welded steel anchors were designed. And through the 3D simulation, they were precisely aligned with the coordinates in the safety cage system, and firmly anchored down to the concrete floor. By only attaching the anchor to one side of the log, this gave the band saw a lot of room to move. Finally, after repeated simulations in the software, I finally chose to use the cutting method along the direction of the log to cut out thirteen pieces of wood material with a thickness of only one inch. They were spliced and assembled according to the previous simulation, and finally formed a building facade with a height of nine feet. And because of its own texture and splicing method, such a building facade does not need extra structure, but only a foundation, then it can stand independently. So, a set of light steel structures were designed to support the façade to float in the air, which seems delicate and light. It can be said that after the light steel structure was fixed into the foundation and the façade itself was waterproofed, a corner of the building has been completed.

It is worth mentioning that, thanks to the high precision of the robot arm and chain saw itself, and the spatial stability brought by the anchors, the final cut wood materials were very precise. Although they are all extremely heavy tools, they can produce such delicate results. It is amazing that all the mechanical technology and computer information technology are finally reflected on the chain saw concentratedly. Moreover, only the ends of the whole log were used for fixing, and more than 90% of the materials were completely used. At the same time, steel anchors can also be used repeatedly to cut different logs later. It is safe to say that cutting accuracy, complexity, and material saving are beyond traditional technology.

Finally, imagine how novel buildings can be produced by such a construction method — if there are many kinds of curved wooden surfaces, then when the facade is peeled off the ground, windows would be naturally formed; or when facades are enclosed, It is more appropriate to use skylights for natural lighting; or because of the curved surface itself, the facade and the roof can be completely integrated at certain moments. In terms of building sustainability, this architectural design method has strong advantages: first, wood is a sustainable material; and this cutting method maximizes the use of wood, and combines multiple technologies to create high-precision and high-complexity building materials. At the same time, new architectural typologies can be explored. Because such architectural vocabulary is determined by building materials, it generates completely unconventional construction logic and architectural spaces.

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AUTHOR

YANG ZHAO

I graduated from Tianjin University with a bachelor’s degree in Engineering in Urban Planning and from Cornell University with a master’s degree in Architecture. I worked for BUZZ Beijing, STR NYC, Gensler Boston, and SOM Chicago; currently, I am working for Pfeiffer Partners Architects in Los Angeles as a Project Architect, majoring in theatrical and musical Architecture Design. I started my own brand UYANG Architecture in 2021, and already won several major international awards and publicized several articles and projects on Archdaily, Gooood, Archcollege, Archposition, etc. I am also a commercial pilot, flight instructor, and aviation business owner.