DIGITAL DESIGN + FABRICATION SM1, 2017 M3 JOURNAL - SKIN & BONES Alice Shan Jiang (783943) Chester Wong (618157) Nicholas Collins (758427) Steven Lee (685769) Tutor Name: Amanda Tutorial Group: Tutorial 7
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Introduction During the module 2 presentation, our group was able to receive invaluable feedback from both our assigned tutor, Amanda, and guest critic, Chen. Most of the feedbacks were focused on how we should be pushing the limit of the perspex frames more (reduce frame thickness, decrease frame width and hole size), and how the joints of the perspex pieces should be incorporated into the overall design. The prototype which focused on building curved surfaces (shown on the right) was better received, as it produced interesting curvature through bending the perspex pieces. On the other hand, the second prototype which explored the idea of utilizing two different types of string was not as interesting as the other counter-part. Hence, we decided to focus mainly on developing the first prototype further.
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Design development The first design which we developed after module 2 focused on the idea of how similar-sized triangular pieces can be used to populate the frames around the body, and then use ideas similar to Naum Gabo’s linear construction sculptures to form a layer of skin on top by using strings/wires. The strings will also serve another purpose, which is using tension to hold all the
About the Images
Three Rhino renders are shown at the bottom, which illustrates the model which we were attempting to build.
We aim to achieve this through the construction method of using the flexibility of perspex to create curvature, and then forming skins between each element by threading strings/wires between them.
However, this design development’s growth did not meet the group’s expectation, mainly because it was not particularly pleasing aesthetically and was not a good indicator on how we wanted to express our personal space in a three-dimensional world (the elements were simply too repetitive, and they were not able to provide a good sense of contrast). Therefore we eventually moved on to another design which involved building a frame around the subject’s neck and then extending modules on top and around the frames (shown in the next 2 pages).
On the right, we have two of Naum Gabo’s linear construction sculptures (top and middle images), which we were aspired to create something similar, but yet unique in our own way.
In the end, our design will be able to extend personal space based onthe original concept drawing which we came up with during module 2 (shown at bottom right).
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Design development + fabrication of Prototype V.2 Through experimenting with the existing perspex pieces we have obtained from laser-cutting. We were able to produce interesting shapes and frames which we thought had potential for further development. The first step we took was building a large hollowsphere-like object (top image on the right) which is made out of smaller triangular frames with tiny holes positioned near the outer rims. Due to the flexibility of the perspex frames, we were able to bend various element and join them all together with relative ease. However, the more challenging part was how we could position this large element onto the body while maintaining overall structural balance, so that the frame would not fracture or fall apart once the assembly is complete. After spending some time experimenting the positioning on our team mate, we were able to successfully attach the large spherical element onto the body of the subject (shown in middle and bottom images), while ensuring it is self-balanced. Unfortunately, due to the fragile characteristics of the perspex frames, any abrupt movement from the subject or external impact mean that the overall structure would fall apart.
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Rhino Modelling of Prototype V.2 This is one of the parts which we overlooked initially, as the skin and bone material system often involves bending the elements, which means there was no way which we can depict the real-life model with 100% accuracy. Therefore we took another approach which approximated the overall design to a certain extend. During the modeling phase, our group has attempted various different ways on how we can accurately simulate the curvatures resulted from bending the triangular pieces. However, the Rhino commands such as “bend” and “scale” were simply not able to give an accurate output. We eventually opted for the easier path of modeling the second skin’s frames by modifying each shapes individually and place each of them in their corresponding position as accurately as we could. Fortunately, the three-dimensional Rhino digital models were not compulsory for the fabrication process, as we only needed to draw the two-dimensional cut-outs for perspex sheets for laser-cutting.
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Reading Response Wk 6 Architecture in the Digital Age - Design + Manufacturing/ Branko Kolarevic, Spon Press, London c2003 Kolarevic talks about different methods to which a 3-dimensional object can be constructed. This includes: two-dimensional fabrication, where a flat two-dimensional sheet is cut using a laser or other method (shown in figure 1). We found it weird that water can be more potent to cutting thicker materials than a laser due to its high pressure. Another method is subtractive fabrication. This involves taking a large solid and chipping away like a sculpture. However, this is done through a computer programed drill. A problem with this method is that the machine can only cut from a birds-eye view, unless a 5-axis system is used. We used this method to cut out the pieces of the bone structure of our design. Once cut the pieces could be bent to create the desired shape. Lastly there is additive fabrication, where the object is built from the ground up. This includes 3d-printing and spray on techniques. This method can be time-consuming for large projects and requires a structure to be built up as well to create overhangs, wasting material.
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Kolarevic then talks about the construction process. He talks about how three-dimensional surfaces can be transformed to work with the digital design strategy’s. One method the creating a rib/bone structure to which the surface can bend around. Another is to transform the curved three-dimensional surface into a ruled surface made up of straight lines. We found that on their own these techniques can reduce the organic form of the surface, and a combination of them can create a better version of the desired object. We used the lines of a ruled surface as the wires of our design (shown in Figure 2). This allowed twists and a weirder form for our design. One useful tool in adding these wires in the design was grasshopper, which helped us break up and link the pieces. Another aspect of the assembly is the material used. This impacts the look of the final object as well as how heavy and strong it is. Recent introduction of malleable and formable materials has allowed these more ambitious shapes to take form. Due to the different chemical structure of these materials the colour can be manipulated to change the visual effects of the material. I found the section on how the strength of carbon nano-tubes will allow architecture to be able to produce even more creative designs quite interesting despite the current failings to make the material work (non-toxic).
Figure 1: Laser cutting in action (above)
Figure 2: Our design of using strings to form surface (below)
Reading applied to design How fabrication process and strategy effected our second skin project.
We used Rhino to model our design over a mesh of a person. Then the pieces we wanted could be transformed to work with a two-dimensional plane for laser cutting. Having a body mesh to work with means that we can model certain pieces such as the shoulder support more accurately, without having to take various measurements in real-life. The ability to laser cut pieces meant that we could trial different lengths and shapes of the pieces as well as different joining mechanisms, centre pieces and methods of connecting the string to the Perspex bones. The ability to model and quickly cut the pieces allowed us to test the different joints and allowed us to experiment with the string order and work out the best and fastest ways of assembling the overall design. We are very fortunate to have tools such as Rhino and Grasshopper which work interchangeably in our project, allowing us to fully visualize how the strings would look from every angle, without having to go through the whole threading process (shown on the right). This not only saved us huge amount of time, but also allowed us to quickly evaluate which design was the most desirable and whether they are achievable in real-life. As we progressed through fabricating basic pieces from simple triangular pieces to more complex pieces with multiple curves, we learnt more and more about the strengths and weaknesses of the tools at our disposal. While instruments such as Laser Cutter can be very flexible, allowing us to cut almost every possible shapes out of perspex, there is also an inherent limitation, which is that, if the curves of the design are too close to each other, the laser beam could possibly melt the region in between.
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Reading Response Wk 7 Digital Fabrications: architectural + material techniques/ Lisa Iwamoto. New York: Princeton Architectural Press c2009 We found the shift from Cartesian geometry to describe a surface to curvilinear system quite interesting. This involved how standard geometries can be transformed from (x,y,z) to the vectors U and V to better form and describe new systems. These new and alien geometries have become available for use due to the use of digital design tools, which have a mathematical basis that allows the creation of smooth curves that can cover a desired space. It is fascinating in the reading to see how this use of digital design tools has transformed objects to be weirder in an abstract way but retain the flow and smoothness of design like the Mafoomby, which the inside is smooth and free flowing, but the geometries would be much hard to accomplish by hand. The Perspex pieces of our design were created by curve tools in Rhino, which allowed us to smoothly define their shape, which would have been much harder via conventional means. Like in the reading, these pieces were not our starting point, but developed through the design process as well as their purpose and positions. Following this, we moved our design from more conventional perfectly circular pieces to ones that were non-linear (quadratic or higher basis for their curves). This meant our design was less flat and became blobby and angular. Mafoombey Acoustic Space By Finnish architecture students Martti Kalliala and Esa Ruskeepää, with architect, Martin Lukasczyk (2005)
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Reading applied to design Implication of digital fabrication on our design, after referencing from lectures and readings. Like the Digital Weave in the reading, our design required exact parts. We needed to cut pieces that fitted the shape we wanted and be easily constructed. Ours differed in that we needed our pieces to be joined in different ways as we explored different forms and impacts on personal space.
How the perspex pieces join together through a pre-specified cut-out.
It is also through the digital design techniques that we were able to fit our indent for the string onto the pieces. These techniques meant we could bend and conform the repeated shape onto the edge of the piece, without flattening the edge to let the indent easily sit on it.
Transition from the old slot design to the new one
The relationship between how the laser cutter works and the Perspex also influenced our design. That we could just cut a line in the Perspex rather than cut off a piece to fit the string meant that we could attach the wire easily and in different ways.
While the old slot design was arguably easier to wire, it does have its a fatal design flaw, which is that the circular cut-outs are too close to each other and therefore the laser-cut job was rejected on arrival, due to the reason that the laser cutter’s extremely high-temperature beam would most likely melt the perspex between each slot. Furthermore, this design also has a low density of slots, which would not suffice the requirement we trying to achieve.
The wires were placed in a way so that they interfere with each other to change how the object behind them is viewed from different angles. The use of digital design software allowed us to simulate the connections between the wires, see the body from different angles, and explore different ways of achieving this affect.
The new design originated from a conversation with a technical support tutor who gave the ingenious suggestion of simply using the straight line cut-out from laser-cutter, which would provide just enough room for the white bead strings to fit through, but also greatly improve the density of the strings.
Old Slot Design
New Slot Design
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Prototype development
Complications arose with the previous prototpye due to the complexity of the individual structures which were made and the scope of what we were trying to achieve. There were concerns about the practicality and aesthetic quality. Previously, we were trying to create a model which would cover the entire upper body. As a result of the complications, we decided to scale down the model to only encompass one side of the body. Materials from the previous prototypes were used first and played around in order to get some inspiration on how to remodel it. We settled on a model which would rest on one shoulder as opposed to resting around the neck We looked back at our first prototype in Module 2 as an inspiration to create an elegant and flowing structure instead of the modular elements of before.
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Prototype optimisation
Perspex was used as the main material throughout our project. Our designs always made up off various elements which varied in size but were also all fairly slim in proportions. Thus, we were able to fit all elements plus some extras into one sheet when sending it in for fabrication. At times we pushed the limit by placing elements very close to one another to try to save space and was rejected once as our elements were less than 2mms apart. Spare elements were always created due to how often they would break under preassure. Some uniformity was also acheived with certain elements not just as an aesthetic descision but also a practical solution. Proportions, scale and measurement could be easily resolved among pieces which had certain similarities in their shape and design.
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Prototype optimisation
The key element in our model is the usage of strings which span across the entire structure to create an interesting volume which would also serve as the second skin. The bone structure had to also be optimised in order to find out what kind of shape would allow for interesting volumes.Due to this, experimentation with the wiring was a main part of the design process. We experimented with different densities, heights, curvatures and patterns with which to wire. The result is a structure which combines all of these elements. Strings span to and fro from different elevations and planes and some of these sequences are inverted to create a more interesting shape. A few changes to the bone structure was also made to facilitate this. Certain elements which were deemed to have too‘sharp’ an angle. They were redesigned into a more curvy, long and elegant member. This was done in order as these characteristics would result in a membrane with a more consistent and elegant.
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The implementation of such elements was generally sucessful in achieving desired effects and thus, more elements were created to be attached to the structure. These elements varied in shape and size but all shared the same characteristics as stated before. Their implementation was used to help facilitate more complex wiring which would result in a a more interesting volume. Their placement on the existing bone structure was also used to try to cover any gaps or ‘dead ends’ which were part of the old design.
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Prototype optimisation
A key element of what makes our model work is how the bone elements bend in order to form curves. As a result, the thickness of the perspex and the shape of the elements themselves had to be reworked serveral times. The thickness of the perspex was reduced from 3mm to 2mm. While this did result in an increase in the number of broken pieces during the process, the bending effect which was achieved was a greater gain. Certain elements had to be reworked several times as there was always an issue and conflict between aesthetics and stability. Modules were slimmed and rounded out at the start in order to make them less conspicuous and flow better with the structure. However, this resulted in the edges of the elements being very prone to breakage. In the end, we reverted back to a flatter design but still kept the curved slimness. The shoulder piece also went through a similar redesign, with supports added to brace a much thinner structure. They were ultimately removed and changed as the supports weren’t useful and the element retains its original volume as it is the main supoorting structure for all elements. 14
The wiring process is the most important part of the model. Thus, the slots in which to facilitate the wiring went through numerous design changes. We started out with three prototype for the slots in our orginal protoype. They consisted of holes, jagged edges and one which combined both. It was decided that jagged edges were not aesthetically pleasing and were very difficult to keep consistent on the model, so hole slots was chosen at this stage. In order to keep the holes less conspicous, they were significantly reduced in size and continued to be reduced as we moved on with the design. The final size was a hole which was 2mm in diameter. This allowed the hole to be small enough that it won’t be easily seen. However, another complication arose. The holes’ size and its quantity throughout the model made wiring a very tedious task and wires needed to be pulled fully through before we could move on to another hole. To solve this, holes with curved slots were designed to get rid of the need for threading. Strings could be slotted through andhoused in the hole and this would make the wiring process much faster. However, another complication arose. This new design took up much more space and there were less slots than the previous designs.This meant that we had to sacrifice some density in the string membrane. Thankfully a solution was found. Drawing a line on the Rhino template would allow the laser cutter to cut a slot which was just wide enough for a string to fit through. These thin line slots were thus used in the final design and much more slots could be placed on a single element.
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2nd Skin Final Design
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Our second skin structure aims to give off a non-intimidating feel. The user is able to be seen from a distance due to the translucency of the membrane but as a person comes closer, the membrane can be clearly seen and acts as a barrier against others. The soft curves of both the membrane and the bone structure seemingly blend together and also give a gentle look to not repulse others. However, it is also elongated at the shoulder point to prevent others from touching the user and keeping a distance, be it from the front or back. The structure also serves as a slight view obstructor as eye contact is a big issue with personal space. From certain angles, the user is slightly obstructed from view and others from the user.
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Fabrication Sequence
Step 1
Step 2
Step 3
Prepare the laser-cut template, send it to the FABLAB for cutting.
Thoroughly inspect all the parts and ensure that all the pieces are without defects.
Attempt to construct the frame from using bottomup approach. If any pieces break during construction, and there is no additional back-up pieces available, re-evaluate the current design and make improvement/refinement if possible and then start from step one again.
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Step 4
Step 5
Step 6
Begin threading by using the white bead strings and strictly follow the pre-designed arrangement from Rhino/Grasshopper.
Conduct quality control, thoroughly investigate whether the strings are tightened well enough, and whether there is still room for improvement. If so, remove current wiring and re-attempt step 4.
Final product is ready for testing.
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Assembly Drawing Components Legend
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1
Main Shoulder Frame
x1
2
Triangular Joint Pieces
x3
3
Curved Members
x3
4
Long Curved Members
x2
5
Sharp Claw Members
x2
6
Shoulder Support
x1
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Additional: 3mm Nut and Bolt for holding the bent pieces in place.
Assembly Instructions
Close-up of nut and bolt mechanism
Step 1 The main shoulder piece is fixed in position. Step 2 The three triangular joint pieces are attached. Step 3 The “curved members” and “long curved members” are carefully attached, with an attempt to minimise any fracture/cracks from developing in the perspex. Step 4 The “curved members” and “long curved members” are bent into their designated position on the main shoulder frame, then the 3mm bolt is used to secure five layers of perspex through the five 3mm holes, and the nut tightens everything in place.
Before Bending After Bending
(Details are shown in photos on the right.) Step 5 Attache the sharp claw members and shoulder support piece.
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2nd Skin
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Appendix Bibliography Iwamoto, L., 2009, Digital fabrications: architectural and material techniques, Princeton Architectural Press, New York Kolarevic, B., 2003, Architecture in the digital age design and manufacturing, Spon Press, London
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