STUDIO AIR PART B JOURNAL NAME: YU CHIA LIM YEAR: 2018 SEMESTER 1 TUTOR: CHELLE
PART B: CRITERIA DESIGN
B .1 B .2 B .3 B .4 B .5 B .6 B .7 B .8
research field case study 1.0 case study 2.0 technique: development technique: prototypes technique: proposal learning objectives & outcomes appendix: algorithmic sketches
Figure 1. “Green Void / LAVA”, Archdaily, 2018 <https://images.adsttc.com/media/images/55e8/9eff/e258/4674/1c00/00c4/large_jpg/1868790740_081210-green-void-build-up3-cb.jpg?1441308388> [Accessed 8 April 2018].
B. 1 RESEARCH FIELD GREEN VOID BY LAVA
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he Green Void installation by LAVA in 2008 at Sydney was a demonstration of the capabilities of digital design in creating complex forms that can be fabricated easily. Stretching across the open space of the atrium in the Sydney customs house, the arms of the structure latched to the building like a parasite. The design to fabrication workflow was entirely computerised, from the 3D modelling of the form which was founded using minimal surface tension to the connection of the individual fabric strips through mechanical seaming1. This project was chosen as my research field as its form strongly relates to the case study precedent for my group’s design proposal. I was interested in the design possibilities that can be generated through this form throught the 3D modelling software, Grasshopper.
1. “Green Void / LAVA”, Archdaily, 2018 <https://www.archdaily. com/10233/green-void-lava> [Accessed 8 April 2018].
B.2 CASE STUDY 1.0
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ased on the research field I have chosen in B.1, I used the example grasshopper definition from the LMS to generate new forms and created the matrix on the following page. There were 3 methods given to create this form and I chose to use the exoskeleton because it is the easiest to manipulate within grasshopper. Method 1 was to create a mesh from a set of curves drawn in Rhinoceros which is useful if the desired form is already known, but since I am still experimenting and exploring possibilities, that method is not suitable. The third method involved creating a set of meshes in Rhinoceros and using the welded mesh to create a tensile membrance in Grasshopper. I did not choose this method also because of the difficulty to change parameters as the form is already fixed in Rhinoceros.
Grasshopper definition
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his definition is produced using the second method which involves an extra plugin named Exoskeleton. Using Exoskeleton, I was able to create a mesh that has inputs that I can manipulate as parameters. The limitations of this method are also present in the event when complicated shapes have to be created and the membrane created does not produce the effect desired.
Figure 2. Grasshopper definition for reverse engineering of Green Void by LAVA
Exoskeleton allows for a quick mesh to be generated around lines which are inputted into the component and also generates a variety of meshes by the manipulation of radii, nodes, capping and sides of the mesh surrounding the line. I used it here to generate the desired mesh for the mesh relaxation.
Weaverbird plugin in grasshopper allows me to extract the mesh edges to be used the spring line for the mesh relaxation component. The vertices of the openings are found using the naked vertices component and attached as anchors for the mesh relaxation process
Merging the spring length and anchor points allow for the bouncy solver, a component from the Kangaroo 2 plugin in grasshopper to calculate the mesh relaxation and simulate the behaviour of fabric or a membrane being stretched in the model. The length of the spring can affect the tautness of the fabric, which is explored in the matrix.
Parameters varied Sides (number of sides for struts in exoskeleton component) 5 10 15 20 25 Start radius (radius at the start of each line in exoskeleton component) 5 10 15 20 25 End radius (radius at the end of each line in exoskeleton component) 5 10 15 20 25
Node depth (offset depth for nodes in exoskeleton component) 0 5 10 15 20
Division (segment division length in exoskeleton component) 20 40 60 80 100
Length of spring for mesh relaxation 0 5 10 15 20 Figure 3. Matrix of variables for reverse engineering of Green Void by LAVA
B.3 CASE STUDY 2.0 Mars Pavilion by Form Found Design
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his case study acts as a precedent to my design proposal. The robotic fabric formwork used and the form generated in this precedent are key aspects that we are exploring through our group design project for this studio. The design of the Mars pavilion involved a form-finding process of creating a hexagonal mesh and fitting it to a gridshell generated from a catenary arch2. However, instead of using a similar form-finding process as the precedent had, we decided to adapt the form and the fabrication method to other ways of creating the structure as we did not want to be limited by a gridshell.
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n terms of fabrication, with limited resources and equipment, we can only try our best to create similar forms even though there may be limitations to our own created formwork as opposed to the accuracy and precision produced by a robot. Instead of using robotic arms we are using mechanical arms which are manipulated manually during the process of creating the form. 2. â&#x20AC;&#x153;Form Found Designâ&#x20AC;?, Form Found Design, 2018 <https://www.formfounddesign.com/palm-springs-pavilion> [Accessed 10 April 2018].
Figure 4. Alice Morby, â&#x20AC;&#x153;Fabric-Cast Concrete Method Could Be The Future Of Constructionâ&#x20AC;?, Dezeen, 2018 <https://www.dezeen.com/2016/05/19/ron-culver-joseph-sarafian-fabric-forms-cast-concrete-roboticarms-construction-method-of-the-future/> [Accessed 15 March 2018].
Grasshopper definition Similar to the research field, this form of three branches which creates a simple Y shape which relies on the tension of membranes or fabric to form its shape. Hence I have decided to apply a similar method to create this Y shape. Initially I had created it using method 3 which is welding meshes in Rhinoceros to input as a mesh in Grasshopper but I found that method to be too limiting and difficult to manipulate as there are not many parameters to play around with. With the exoskeleton method, it is more flexible and allows more room for variation as well as complicating the form further by adding branches to the existing Y shape. This expands the design possibilities of the bike shelter.
Figure 5. Grasshopper definition for reverse engineering of Mars Pavilionby Form Found Design
With the Y shape, 3 curves act as inputs into the line component of the exoskeleton. However, because the radius of the ends and starts of the curves can be changed in the exoskeleton, the curves must be drawn in a certain sequence to ensure that the radii of two ends match up.
Similarly, weaverbird and naked vertices are used to obtain the length of the spring and anchor points for the bouncy solver. The length can be set to 0 which makes the tensile membrane stretch to its maximum so that it is in a very taut state.
With the merging of components of spring length and anchor points, the tensile membrane can be generated and the variations created are shown in the matrix on the following page.
Parameters varied Sides (number of sides for struts in exoskeleton component)
Start radius (radius at the start of each line in exoskeleton component)
15
25
35
45
55
15
25
35
45
55
0
10
20
30
40
0
2
4
6
8
Division (segment division length in exoskeleton component)
Length of spring for mesh relaxation
Figure . Matrix of variations for reverse engineering of Mars Pavilionby Form Found Design
Since the end radii and the node depths of this form shows no changes in the tensile membrane generated from them when they are manipulated, these parameters are not included in this matrix. The ideal form chosen was one with 35 sides, 15 start radius, 30 end radius, 0 nodes and 10 divisions with a spring length of 0. This chosen form acts as a control for the matrix where the rest of the variables are fixed according to these inputs while one variable is changed.
B.4 TECHNIQUE: DEVELOPMENT
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he development of the Y shape to suit our design proposal is required as we did not want to use the Y shape merely as a module as we thought that it would be too limiting for our design intent. Other developments that are required include creating some sort of branching structure that can has its own form and can be structurally sound.
These forms express the possibilities of the system by branching out into different directions and creating more interesting forms and voids unlike the regular hexagonal void of the Mars Pavilion. It is essential to our design brief that we are able to vary the voids and branches of our design proposal.
I also explored the possibilities of developing this shape in a lateral direction instead of vertical direction, to create forms like a fallen tree branch which can provide seating spaces as well as gaps and void at which bikers can park their bikes.
B.5 TECHNIQUE: PROTOTYPES
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aving no experience in casting and creating forms using concrete, prototyping is an important stage we have to carry out to gain a better understanding of our system and materials. Therefore, we experimented with our materials and chose the suitable ones to create prototypes out of. We were satisfied with the results of the prototypes but there is much more to be improved on, based on feedback we have received, such as considering the possibilities of using lightweight aggregate such as paper pullp or styrofoam to reduce the weight of our individual Y modules. The density of the cement can also be a variable which may help us improve our concrete casts. We also have to consider the joints and connections of our Y modules as they would have to be cast into the concrete to ensure a more stable connection.
Figure 7. Second prototype of Y shape.
Stage 1 planning and conceptualisation The precedent Mars Pavillion was fabricated using robotic arms and more advanced equipment which are not accessible to us at this point in time due to our lack of experience in the subject and skill to use those advanced equipment. Hence, we decided to create a simpler version of the fabrication technique using timber formwork and mechanical arms attached to the formwork to control the outcome of the prototyping process. The design of the formwork was first suggested by our tutor and then further developed by us. This formwork did allow us to cast concrete into the Y-shape and produce successful results for our prototyping stage, but there are several improvements that can be made to it. Its limitations included the fact that we can only cast it in an inverted Y shape which makes the forming of the shape influenced by gravity with more concrete pooling at the bottom of the branches and also the lack of pressure to push the concrete into the fabric and stretch it to its limits, as this was carried out in the precedent using pumps which we did not have. Knowing these limitations can help us push our formwork design forward in the next stages of the design.
First sketch of the formwork and fabrication method of the Y-shape
Figure 8. Schematic diagrams for formwork design..
Usage of steel cables to create a grid system at the top of the formwork and configuration of timber mechanical arms which will hold the fabric in place while concrete is poured
Connection of fabric to pipes to create an opening at the top and a cap over the end of the branch and connection of fabric to the robotic arm
Stage 2 framework setup and concrete testing Step 1 concrete tests
Concrete tests were carried out in simple formwork to test out different types of concretes and ratio of water added. This aids us in deciding which concrete to use in our prototypes.
Figure 9. Sample 1: 700g concrete + 110ml water
Figure 10. Sample 2: Geelong Builders cement + 110ml water
Figure 11. Drilling into timber pieces that are screwed together to create the frame of the formwork.
Figure 12. The finished formwork with a grid system at the top and two mechanical arms which allow manipulation of the location of the arms within the formwork system.
Figure 13. Sewing the Y shape into the fabric using a sewing machine
Figure 14. Sewing the Y shape into the fabric using a sewing machine
Step 2 timber formwork
The timber formwork system was created according to the planned diagrams using timber pieces obtained from the Fabrication Lab and Bunnings.
Step 3 sewing fabric
We initially started by handsewing the Y-shape to the fabric but due to the lack of experience and skills we did not come out with a good outcome (prototype 1) and we managed to get our hands on a sewing machine to sew the other fabrics.
Stage 3 analysis of materials Fabric type of fabric 24-way stretch shiny nylon Scoop buy knits #3 (off (colour) s5pandex (Cobalt) white)
2-way stretch mesh Lycra (Skin)
Fabric from Chelle (Black)
composition
Polyester and Spandex
30% Lycra and 70% Polyester
20% Spandex and 80% Nylon
80% Polyester and 20% Spandex
test results
stretchability durability permeability
4 3 3
2 4 2
5 2 5
1 5 1
The black fabric was chosen because testing the fabrics have proven that it is the most suitable as it is not too stretchy which makes it withstad weight without deforming under concrete weight, and it is highly durable as well as allows moisture to drip through without concrete leaking throught it.
Concrete Samples
1
2
Composition
700g concrete + 100mLwater
390g Geelong Builders cement + 110mL water
Qualities
- Darker Colour - Heavy inweight - Takes longer time to dry - Tougher to mix
- Lighter Colour - Lighter in weight - Fast drying (~1day) - Easier to mix - Tidier finish and smooth surface
Sample 2 was chosen because of its lighter weight and the lack of large aggregates will not create problems should the sharp edges of the aggregate pierce through the fabric. It is also fast-drying and produces a more desirable finish than the first sample.
Stage 4 prototyping Step 1 mixing concrete
The cement is first sieved to ensure that the concrete particles are fine and no aggregates are present.
Water is first added into the bucket and concrete is added slowly in batches. Concrete is mixed with the aid of a timber batten to stir and and ensure it is mixed uniformly.
The fabric is attached to the formwork before concrete is poured and left ready for the concrete mix.
While pouring, we have to manually push the concrete downwards and tap the fabric rapidly to remove air bubbles existing in the concrete mix.
The next day, the concrete is removed from its formwork (this photo being the result of the first failed prototype of using a material that is too stretchy and clings to the fabric which forced us to cut the fabric open). In the case of the successul prototypes, the fabric is removed by taking off the stitches which allows us to reuse to formwork if needed.
The concrete is laid in a secure and sheltered place as it still contains moisture and needs to fully cure for a longer time.
Step 2 pouring concrete
Step 3 removing the fabric formwork
Prototype results Prototype 1
Prototype 2
Prototype 3
B.6 TECHNIQUE: PROPOSAL
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ur design brief is to create a bike shelter located in the new student precinct which is still under construction. The ongoing construction meant that we cannot really access the site properly to collect data and the only data we could obtain is from the internet. With our precedent in mind, we want to intergrate the form of the individual modules of Y shapes into our design, however, we did not want to be limited by the shape of a gridshell, and this led to many questions and difficulties because we are uncertain of the structural capabilities of our design, but hopefully this will be resolved by using 3D modelling later in the design process.
SITE: NEW STUDENT PRECINCT
SITE ANALYSIS
Using these analysis results we came to the conclusion of choosing the walkway between Frank Tate buildingand the Sidney MyerAsia Centre building as it is very accessible to bikers as well as pedestrians and our design intent is to integrate our branch-like forms with the trees in the campus, and the laneway has trees which serve this purpose as well as provide shade to our design. Our proposal aims to improve student experience through natural, cultural and social engagement. We plan to look at trees on the existing site and study the branches to create iterations of the Y shape form. In terms of natural engagement we want our structure to integrate into the existing environment (maybe with the usage of vine walls) For social engagement, we thought that the bike shelter can potentially become a meeting point. It can provide free phone charging and drinking water fountain.
PLAN AND RENDER OF INITIAL DESIGN
B.7 LEARNING OBJECTIVES & OUTCOMES
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t this stage of the design process I believe that my team and I have been putting most of our focus on creating prototypes and experimenting with the material because we were initially very daunted by the idea of designing with concrete and creating our own formwork. The process was very illuminating and we have gained a better understanding of the materialsâ&#x20AC;&#x2122; behaviour and this will help us proceed with creating models for the design outcome in part C. However, we need to now put our attention to the design proposal and come up with a better proposal as well as fully utilise the 3D modelling tools and skills we have learned in lectures and tutorials. Having received the feedback from our tutors and guest crits, we believe that the next step to our design is to improve on our grasshopper iterations by exploring more ideas and possibilities of our form and putting forward a design proposal which answers our brief and satisfy our interpretation of the functions of bike shelters. It was a steep learning curve for us as we were unfamiliar with the digital as well as physical modelling process of our system, however we have learned a lot in this stage of the studio.
B.8 APPENDIX: ALGORITHIMIC SKETCHES