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87

TetraScript:A ResponsivePavilion, From GenerativeDesign to AutomationGonçalo Castro Henriques

issue 01, volume 10international journal of architectural computing

88

TetraScript:A Responsive Pavilion, FromGenerative Design to AutomationGonçalo Castro Henriques

Abstract

This research is part of a broader investigation into the use of digitaltechnologies in the Architecture, Engineering and Construction (AEC)sector.The intention is to improve the ability of buildings to respond tocontext by proposing a skylight system that can adjust to externalenvironmental conditions and internal functional demands.We call thisresponsive ability customisation.The proposed skylight system canadapt to different geometries, uses, locations, times of day and othercontextual conditions. Customisation can be achieved by static anddynamic processes. Static customisation is achieved during the designprocess by selecting the form and size of the building, as well as thenumber, arrangement and size of the skylights, among other features.Dynamic customisation is accomplished after construction by changingthe skylight aperture in real-time to control interior conditions.Thispaper focuses on the static process to find an adequate skylightconfiguration for a case-study pavilion.

1. INTRODUCTION

Current construction practices take little advantage of the use oftechnology to design, manage and construct feasible building solutions whichcan adapt to their users and location. Few design strategies have developedand implemented responsive systems.

In the current development model, the building industry consumes largequantities of materials, energy, and human resources.The result of thisbuilding model is visible in the built environment, which depletes naturalresources. Compared with the use of resources in nature, the humanapproach exhausts resources faster, without renewing them. Nature adaptsto the environment in order to build and uses fewer material and energyresources [1]. Nature adapts and evolves in time with natural selection,whereas the dominant strategy in the building industry requires vastresources and values economic aspects from a short-term perspective. Inaddition, the mainstream building industry does not satisfy local andindividual demands.

Technology, in general, has been seen as a globalising factor or means ofachieving economic power, whilst its ability to improve local conditions andovercome environmental problems has been neglected.As a result,technology and nature are seen as opposed or dual realities.This researchintends to explore how new technologies could be applied during thebuilding cycle, proposing a system that fosters local adaptation andcustomisation.The proposed skylight system uses digital tools to find asolution that adapts to different geometries, uses, locations and weatherconditions.

1.1 Biological influences: natural evolution and behaviour

The current research was inspired on several levels by the features ofbiological systems.The static and dynamic customisation processes referredto above have parallels in natural systems. In nature, organisms evolve byadapting to the environment in the long term, using a process of naturalselection.This is the case with certain vegetables whose shape and surfacetexture enables them to control their inner temperature in hot climates(Figure 1).The process of finding an adequate configuration for a buildingusing static adaptation can be compared to natural selection over time. Inaddition, some organisms have behaviour mechanisms that allow them toreact to changes in local conditions in real time. Some plants, such as thesnow buttercup, follow the direction of the sunlight to receive more sun, ina heliotropic response. Others, such as the king protea, open up more toreceive sunlight, reacting to the amount of daylight by responding to non-directional stimuli using photonasty.The process of changing the aperturesof skylights can be compared to such responses.

89TetraScript:A Responsive Pavilion, From Generative Design to Automation

1.2. Static and dynamic customisation

The problem of adapting the pavilion to the context was a matter ofmanipulating its shape in response to internal and external conditions,including both long-term and short-term conditions.Within the context ofthis study, the problem was simplified by using a case study – the design of asmall pavilion – focussing on daylight factors, due to their impact onenvironmental and architectural qualities.

Static customisation is used during the design phase to adapt the shapeof a building to its particular use and location at the time it is built.Thevariables that can be controlled at this stage are basic form, tessellation andtexture and the corresponding values are found in the design stage.Dynamic customisation is used to adapt the shape of the building tochanging internal and external conditions during its daily operations after ithas been built. In this phase the only shape variable that can be controlled isthe aperture angle of the skylights, which determines the pavilion’sconfiguration.

In addition to taking inspiration from the biological systems referred toin the previous section, static and dynamic customisation also has asignificant background in vernacular architecture.To a certain extent,vernacular architecture can be seen as the result of a static adaptationprocess in which spatial and formal solutions are fine-tuned after years ofevolution.Vernacular architecture contains examples of static adaptation inwhich ornamentation is used to solve various problems and define spatialqualities. One example can be found in Islamic architecture with the use ofmashrabiya screen walls [2].These screens provide ventilation and shade,and filter light to the interior.There are also examples of dynamiccustomisation, for instance, in the use of kinetic structures [3]. However,although the desire for responsive architecture is an old human aspiration,the advent of digital technologies brings increased opportunities.With thedevelopment of computer technology, more powerful tools are nowavailable for designing spaces that respond to users and the environmentusing static and dynamic processes.

� Figure 1: Above: Examples of

vegetal customisation to

environmental conditions: skin texture

of durian and jackfruit resulting from

natural adaptation; Below: behaviour

mechanism of the king protea,

responding to daylight by opening in

the sun.

90 Gonçalo Castro Henriques

Literature on this subject includes several examples of work using staticand dynamic customisation. Static customisation has been used, for instance,to find adequate configurations in response to functional (Duarte [4]),structural (Shea and Cagan [5]), acoustic (Monks, [6]), and environmental(Caldas and Norford [7]) requirements.These examples of staticcustomisation mainly use optimisation techniques to find appropriateconfigurations, whereas the dynamic examples found in literature on thesubject do not, due to the time required to reach a solution, which preventsthem from providing a response in real time.The system proposed hereintends to bridge these two strategies by first using static then dynamicadaptation, based on heuristic search methods to find adequateconfigurations in real time to avoid the lengthy convergence time typical ofoptimisation methods.This article focuses on static adaptation, whilstdynamic adaptation is addressed elsewhere [8].

1.3. Research areas

Digital tools are used to enable and link different research phases in a non-sequential process. In order to develop design, simulate, manufacture andcontrol, the following phases are required (1) the generation of designsolutions according to the geographic location (scripting), (2) a practicalapplication to manufacture a test pavilion (fabrication) (3) the developmentand implementation of a control system to manage the skylight aperture(automation) (4) a simulation process to set different skylight configurationsand calculate the performance of the corresponding daylight values, aprocess to evaluate and interpret the results and select the best solutions,and a mechanism to predict other situations and act accordingly in realtime. This article will focus on the first and second research stages, whilstthe third and fourth stages will be addressed briefly and detailed in a futurepaper.

In the first stage (scripting) an algorithm is scripted using Visual Basic totessellate a given surface and create the skylights. In order to control theamount of daylight in the interior space, a pyramid-shaped skylightcomponent was devised with four faces that could open by rotating on theirbase to control the entrance of daylight.A parametric strategy enabled a setof solutions to be generated with variations according to the number anddimensions of the skylights. One solution was chosen for each specificsituation and the solutions were evaluated manually, although the idea is tofurther automate the selection process.

In the second stage (fabrication), the physical situation, materialproperties, and dimensions are considered in order to select the bestconfiguration for the case-study, and a structural and fabrication strategy isdeveloped in accordance with the material selected, in this case orientedstrand board (OSB) with metal connectors. Previous fabrication experienceswith other wood derivate products were taken into account [9].The


particular geometrical features of the TetraScript pavilion highlight theconnection system as an important factor in ensuring structural integrityand feasible assembly.The fabrication and assembly of a full-sized prototypeprovided an opportunity for testing the process and advancing the research.

In the third stage (automation) a modular control system was designedto operate and control the aperture values for the skylight panels.Thissystem uses the data collected from the simulations described below andcombines this information with real-time data obtained by light sensors.Thedata collected can be transmitted to a computer program that selects thebest configuration for the skylights and then operates them by transmittingthe aperture values to a programmable logic controller (PLC) thatcommands the actuators in real time.The automation system was tested ina skylight with actuators.

In the fourth stage (simulation) the parametric system developed wastested by attributing a location and values to the previous variables.Thedifferent configuration strategies were evaluated using Radiance daylightsoftware by setting different heuristic strategies to establish certain visualconditions inside the pavilion, namely illuminance and visual comfort. Theresults were stored in a database, and a process for previewing othersituations was developed.The use of heuristics reduces the search spaceand provides real-time information on the behaviour of the system whichenables the indoor daylight values to be controlled [8].

2. GENERATIVE DESIGN ALGORITHMS

The algorithm definition is parametric – i.e.it uses relational definitionsinstead of metric ones – so it can be used to tessellate different surfaces.The first input for the program is a surface that is tessellated with skylightcomponents.The creation of the surface and its decomposition intogeometric components can be achieved manually using standard commandsin Rhinoceros.The Nurbs geometry definition facilitates the creation ofcomplex curved surfaces that would be difficult to produce using standardCAD programs. Conversely, planar components are easy to create in bothprograms. Nevertheless, as creating and populating a complex surface withcomponents in Rhino can be a repetitive procedure if carried out manuallyand would require considerable effort and time, these procedures wereencoded in an algorithm implemented in RhinoScript.

The algorithm takes a surface that can be created using pre-definedRhino commands as its first input.The next input is the number of divisionsof the surface, set by the U and V values.The number of divisions of theoriginal surfaces determines the number of skylights and the size of thebase of each one.The decision regarding how many divisions can be createdin each direction is based on the available material dimensions for theskylight, aesthetic criteria and/or other factors. The resulting sub-surfacesand their corner points are used to define the skylights, and are stored in an


array. Using a for-next cycle this data is called up and used to create adiagrid and the corresponding sub-surfaces, which constitute the skylightbases.The creation of sub-surfaces involves using a defined function thatoperates until the tessellation is complete, taking odd and even rows intoconsideration and trimming the edges.A normal vector is then created atthe centre point of each sub-surface of the diagrid; the end points of thisnormal vector define the pyramid’s apex and its triangular faces are createdby connecting the vertices of the quadrilateral base and the skylight apex.The skylights can open by rotating the triangular panels around the edges ofthe lines shared with the quadrilateral base.

The routine enabled a set of solutions to be tested - instead of just one- by changing the parameter values in the script.The number and size of theskylights and their components can be defined by using a differentassociative logic.The skylights can be perpendicular to the ground andindependent of the surface, or perpendicular to the surface, thereforedepending on local curvature, and their height can be associated withrandom values, specific factors, or predefined values. It would take aconsiderable amount of time and painstaking work to generate and testthese variations without a script and the proposed process thereforeprovides a solution to these drawbacks.

2.1.The user interface

Different interfaces were developed and tested to create and manage theconfiguration and aperture of the skylights. In the first experiments dialogboxes, sliders and other form classes in visual basic were used to change theaperture of the skylights.These interfaces, which were used to input data,are friendlier than text language, and can be used by those without codingexperience. In this phase the values that were introduced were notexplicitly related to the input surface geometry and different interfaceswere therefore proposed using Visual Basic.

The first interface used values stored in Excel tables as input.Thesevalues were entered manually into an Excel spreadsheet and the number ofcolumns and lines in the table were the same as the number of skylights.The algorithm written in VisualBasic requires input in the form of an arrayof values that are set in the Excel table. After defining the number of cells(and skylights), the aperture angle was defined by attributing a value to eachcell, on a scale from 0 to 90º. As the skylights are adjacent in the diagrid,additional restrictions to the maximum apertures were defined.This processenabled aperture values to be attributed and the results observed quickly.Different variations were obtained by defining values in the Excelspreadsheet and then testing them.Another subroutine was developed togradually increase or reduce the initial value in the table to simulate thegradual change in daylight and the possible reaction of the system.


The next interface used colour information from a bitmap to controlthe skylights.A small program was written to transform images and theirpixel values into numerical values, then output them into an Excel table.Thistable was then used as explained above for the first interface.The use ofcolour gradients from a bitmap created with image programs such asPhotoshop or CorelDraw to represent lighting and dimming conditionsconstituted an intuitive visual approach to show how the skylight aperturesaffected light and shadow inside. One possibility tested was to use bitmapsresulting from environmental analysis software to determine the skylightaperture, based on environmental conditions.

The third interface was created using Microsoft Visual Studio.Thisinterface used a dialog box with side bars to control the apertures directly(Figure 2) in a more user-friendly way, but had the disadvantage of limitingthe aperture angle to the same value for all skylights, in a synchronizedmovement.To overcome this limitation, different initial values could be setfor each skylight.

The interfaces developed enabled the user to change the aperture andobserve the results, although this choice was not linked to any local data orlight conditions. In order to establish an explicit relationship between thedata collected and the light, an algorithm was created.This algorithm relatesthe local curvature values to the input value of a light vector, defined by theend points.The algorithm compares the daylight vector with the normalvector for each sub-surface of the diagrid.The angle between the twovectors is calculated for each skylight, and a value based on this angle isattributed to the skylight apertures.As the light vector is the same for allthe skylights and their normal vector is different, the skylight aperturedepends on local curvature and the direction of the light.The scriptestablishes a dependent relationship between the input geometry and theposition of the light vector, so that environmental conditions are taken intoaccount and related to local factors.

� Figure 2: Generation of different

solutions and development of skylight

control interfaces.


2.2.A set of solutions for a specific case

In the previous stage, different “populated surfaces” were obtained. Initially,double curvature surfaces were more appealing because of their self-supporting capacity.After defining an algorithm relating local geometry tolighting conditions, it became more appropriate to test enclosed dome-likesurfaces, as they define a completely enclosed interior space, thus avoidingthe need to introduce other elements to enclose the space.

It was decided to build a test pavilion in a 4 x 6 x 3 m area available inOporto (41.8ºN, 80.40ºW). Different candidate surfaces, such as a semi-sphere, semi-spheroid and others spherical surfaces were tested in thisspace (Figure 3).The chosen solution, a semi-spheroid surface, provided thebest ratio between surface area and volume, and due to its geometry, thesurface envelope could receive more daylight (Figure 4).

After designing the input surface, different solutions were generated, takingsolar orientation and tessellation parameters into consideration, namely thenumber, dimensions, height, and orientation of the resulting skylights.Thealgorithm devised was used to test and compare different solutions (Figure3).The supporting measurements suggested that an east-west orientationfor the main axis would allow for greater surface exposure to daylight thana north-south orientation.They also suggested that a greater number ofskylights arranged in the U direction (the spheroid’s main axis) than the Vdirection caused the skylights to narrow in that direction, thus affectingtheir configuration and layout. More details on the generative process canbe found in a previous paper [9].The height of the skylights is related to theprojected shadow that influences the thermal performance of the skinenvelope.This performance feature of textured skin can be observed insome fruits as a means of adapting to extreme environments, as describedin the Introduction.Thermal behaviour is an area that is now beingaddressed in research and it is expected that thermal analysis will helpdecide the height of the skylights in future. Meanwhile, based on the Oportoclimatic properties, a low height was attributed to the skylights to increasethe area exposed to daylight and reduce the shadow effect on the surface.

� Figure 3: Above: Generative

process: candidate input surfaces and

their tessellation, the selected surface

and the different skylight tessellations,

testing different orientations of the

main axis ; Bellow: evaluation of

daylight entrance, unfolding of the

skylight for fabrication, preview of the

support structure and skylight panels.


Although the height of the skylights may be explored, the idea was totest a practical solution and build a physical pavilion within the time availablefor testing the fabrication process. In future, the evaluation of solutions it isexpected to be automated using an algorithm to evaluate, compare andselect the best candidate solutions.This could be achieved with searchalgorithms as genetic algorithms, but the critical aspect of the processwould be to set the fitness function to select the candidate solutions.

3 .THE TECTONIC SYSTEM

3.1.The structural principle

Historically, the use of certain geometries has been influenced by thebuilding technology available.The main goal of the TetraScript pavilion wasto capture the maximum amount of daylight and this concern took priorityover structural optimisation, contrary to traditional building design.Nevertheless, these two aspects are interdependent, as the number,dimensions and orientation of the skylights are important not only incontrolling daylight but also in defining the structural and constructionalfeatures.The challenge was to design a lightweight but resistant dome-likestructure that could receive maximum daylight and this became ageometrical principle that guided the design, structural calculation andconstruction of the pavilion.With this in mind, an alveolar-like structure wasconceived, based on the original convex spheroid surface, using vectorsperpendicular to the surface to define the structure in order to reduce theresulting shadow inside the pavilion.

The construction of physical scale models by hand helped to develop thegeneral construction principles and connections using a feed-back processfor the materials and the geometry (Figure 5).To speed up the process, itwas necessary to automate the unfolding of the skylights, labelling the partsfor fabrication.

The spheroid surface base was tessellated using the algorithm describedabove. It was necessary to introduce a sub-structure that could find anddefine normal vectors for the diagrid in order to define the supportstructure for the skylights.This substructure has OSB bars with metalconnectors and uses metal discs to define the angles between the bars.Thefinal design uses 42 steel connectors, 82 wooden bars, and 140 woodentriangular boards of different sizes.

� Figure 4:Algorithmic generated

changes in skylight apertures

depending on time of day and

direction and intensity of daylight.


3.2 Materials

The material chosen to build the pavilion was oriented strand board (OSB),due to its good density/resistance ratio, relatively low price, and ease oftransportation, handling and fabrication, all qualities that are appropriate forcustomised constructions. OSB offers new material and structuralopportunities as a composite material, but its structural behaviour is stilllargely unknown in comparison with other materials.To overcome thislimitation, and allow for structural analysis, it was necessary to gather dataon its physical characteristics, namely, density, rupture tension, and Young’smodulus amongst other data, which was possible by contacting suppliersand labs that had carried out trials.

3.3. Structural analysis

Due to the complex geometry of the pavilion, it was necessary to find aprogram that could import the geometry and analyse the structure, namelySAP2000 (Figure 6).The original 3D model exported from Rhino had to beredrawn, due to the lack of standard exchange formats between theprograms that translate and interpret the data.The structure wasconsidered as a set of three-dimensional polygonal arcs, disregarding theshell behaviour of the panels, as they are supposed to open frequently.Theloads and their combination were defined according to Euro codes 0, 1 and5. Permanent loads (600 kg corresponding to the self-weight of bars, panelsand automation hardware) and variable loads (0.3 KN/m2 of usageoverhead) were considered as actions that could result from maintenanceoperations in the pavilion.Wind and earthquake actions were notconsidered.The chosen OSB dimensions for the boards for the bars andpanels tested and analysed was 18 mm and 10 mm respectively.The results

� Figure 5: Unfolded plans and the

resulting models assembled in paper.


showed that the structure is self-supporting and can sustain the weight oftwo people for Class 1 risk.The nodes between the bars were consideredsemi-rigid and the number and position of the metal pins linking the bars tothe connectors was calculated, taking the manufacturing process intoaccount.The design uses a solution that is compatible with existing suppliesand hardware.

3.4.The fabrication process

For fabrication purposes, the pavilion had to be broken down into subsetsof components, such as bars, connections and panels. Initial attemptsshowed it was necessary to rationalise this process to avoid an exponentialincrease in the number of differentiated elements.The algorithm was thenexpanded by incorporating a routine to identify and unfold the componentsfor manufacture using CNC cutting machines.The fabrication principle forthese machines is simple.The data contained in 2D files as profiles is usedto control the machine arm with the cutting tool.The routine developedincluded two major steps. In the first step, three-dimensional structuralelements were orientated and redesigned in two dimensions. In the secondstep, these elements were labelled and nested in the OSB boards.Thelabelling is an essential step in guiding the assembly sequence, which involvesvarious components (Figure 7).The routine differentiates between cuttingoperations, drilling and engraving lines, using different layers.

� Figure 6: Structural analysis,

connection and assembly study, with

structure preview.

� Figure 7: Manufacturing OSB boards

and bars using a CNC cutter; an OSB-

steel connection; drilling, cutting, and

welding steel connectors.


Once the routine had been applied, the resulting file was used tomanufacture the components.The manufacturing process involved twodistinct phases: the first aimed to produce the OSB bars and panels, and thesecond the steel connectors.The machinery available for cutting theconnectors had size restrictions and used a variety of software, whichmeant that a specific strategy had to be developed to make themanufacturing process feasible.This included placing small components inseparate drawing files and using an industrial guillotine to cut the steelsheets into smaller units that would fit in the CNC machine.The cutting,drilling and labelling of each connector was done on different machines, sodifferent drawings had to be prepared for each machine and a subroutinewritten to create the corresponding DXF files. If there had been fewerfinancial limitations, the use of a wider CNC machine that used only onetype of software would have been preferable.The process would have beenquicker and would have involved fewer human operations, thus reducing thelikelihood of errors.The connector elements were welded using a highelectrode-tungsten precision method called TIG (tungsten inert gas)

3.5.Transport and assembly

The pavilion was first assembled at the University of Porto Faculty ofEngineering (Figure 8) and then reassembled in Florence at the “Spot onSchools” exhibition at the Beyond Media Festival. During the first assembly,minor adjustments were identified due to inadequate tolerances.Afterassembling several parts, the cumulative effect of small distortions made itmore difficult to assemble the remaining elements and it was necessary togo back and correct them.This was somewhat surprising given the accuracyof the CNC cutting process and could be attributed to the welding process,which was manual.The pavilion was packed up and taken to Florence byroad in two days.The final assembly process was carried out by threepeople and took three days.

� Figure 8:Above: Bars’ assemblage ,

OSB-steel connector and manual

skylight opening mechanism; Bllow:

exterior and interior views of the

pavilion being assembled in Oporto.


4.THE AUTOMATION SYSTEM

Due to financial limitations and in order to manage complexity, it wasdecided to choose a modular system to control the operation of theskylight panels. In the first phase, the system was implemented for oneskylight, to control its four faces.Tests enabled a hardware solution to bechosen and its application to be fine tuned to the structure, although thegoal was to use this mechanism in all the skylights. Several solutions wereconsidered for each modular part of the system, using differenttechnologies. For example, pneumatic, hydraulic and electrical solutionswere studied for the actuators – the components that transmit motion.Thepros and cons associated with the design of these parts and the necessaryhardware were considered.The electric actuator solution selected usesappropriate hardware with fewer components and lower costs than theother solutions analysed.

The chosen system includes a central processor (PLC) and 4 linearactuators, one per skylight face (Figure 9). A program was set to controlthe actuator aperture at the exhibition in Florence, taking artificial lightlevels into account to define the aperture values for the automated skylight.The program run by the PLC takes information on light collected bysensors into account. Due to the security measures adopted by theorganisation, it was decided to control the actuators manually during theexhibition, without using sensors.The remaining panels had a manualaperture controller obtained by modifying the existing hardware to allowfor multiple aperture positions.The goal was to provide for different skylightconfigurations, which were defined by taking aesthetic display criteria intoaccount (Figure 10).

Given the daylight position and intensity values detected by sensors, it isexpected that the system can respond by changing the skylight aperture inreal time using dynamic customisation [8].A program selects the bestconfiguration, which is transmitted to a PLC that commands the actuatorsto change the aperture values of the skylights by setting the daylightconditions.

� Figure 9:Above: Modular

automation architecture, linear

actuators, joints and connection

details; Below: skylight aperture

control with electric actuators.


5. DISCUSSION OF RESULTS

Computation is an emerging design paradigm and has evolved with the“hidden” support of mathematics. New geometries might be the mostvisible aspect of this gradual change, but the deepest change is rooted innew mathematical thinking. Designing and computing a solution are tworadically different perspectives.When computers were introduced intoarchitecture, the design process began by reproducing the ruler andcompass process in a more efficient way to obtain a design solution for aproblem.The use of computational design involves using abstract logic tofind abstract solutions that can be instantiated with parameters to obtainsolutions.Therefore the result of using abstract thinking is a multitude - orset - of solutions, depending on the parameters that are chosen.Theprocess of finding a solution for a design problem using symbolic logic orprogramming language has been termed algorithmic design [11]. Algorithmicdesign uses symbolic logic and formal language, which are the results ofmathematical development. In fact, the mathematical development ofsymbolic logic was necessary in order to support the creation of thetheoretical principle of computation.This principle was devised by AlanTuring before the first computer was built.

Algorithmic design can also use associative logic, another mathematicalachievement that results from the development of topology.Topologyconsiders the qualitative relations between objects instead of thequantitative relations that support metric space.Thus, for example, an objectis defined by being inside a space or next to another object instead of beingdefined only by its dimensions and position in relation to a global Cartesiansystem.Topology introduces local relations and is defined intrinsicallyinstead of extrinsically.This implies that objects are defined on the basis ofan intrinsic space, a local topological space.A triangle, for example, isdefined in relation to a surface by being inside the parametric space of asurface. If it was defined extrinsically it could be defined only by itscoordinates in Cartesian space.Topologically, the triangle – or a surfacelimited by three points - is related to a surface. If this surface has a positivecurvature the triangle will be deformed, but if the surface is planar (withzero curvature) the resulting triangle will be planar. Extrinsic and intrinsicdefinitions are related and the triangle can be translated from localcoordinates to world coordinates in 3D space, although the inverse is notalways true; not every triangle in world space can be translated to the inputsurface.

� Figure 10: tetra-script pavilion at the

Beyond Media Festival, Florence 2009.


But how is this research related to computation, algorithmic design andtopology? The skylight system is formalised with an algorithm that defines arelationship between the components in a local geometry, a surface. Ittherefore defines qualitative relations between components inside a localspace.This system can result in a multitude of solutions depending on thesurface and the skylight parameters for each solution.The TetraScriptpavilion is an instance using a specific input surface with certain skylightparameters. The proposed system can be applied to different geometriesand types of buildings such as pavilions, and not the reverse; it is not apavilion system that can be extended to other typologies.The TetraScriptpavilion might not be remarkable in terms of its form, which may be similarto other pavilions with planar triangles, but it should be noted that itintroduces a relational system of skylights.

This systemic thinking is also related to a dynamic concept of space.Instead of developing a project for a site for a particular point in time only,it has a dynamic vision of time as it is able to adapt to the site and theenvironment.The system adapts by using two static and dynamiccustomisation mechanisms, as previously described. In this respect, ittherefore uses technology, namely computational thinking, but incorporatesa natural adaptation feature related to feed-back and evolution.Anotherproperty of the system is that it is an open system, in which thearrangement of the parts results from local changes, namely in daylight.

The system cannot therefore be defined as a top-down computationalsystem. It uses computation with a bottom-up approach, in which localchanges affect the arrangement of the system, as in natural systems.Thusthe research intends to avoid the isolated view of technology and nature asseparate and one of the goals of the project was to combine the use oftechnology and nature, rather than using technology per se.

6. CONCLUSIONS

The research described in this article is part of wider research that aims toexplore the potential for the use of digital technologies in architecture,particularly for developing more sustainable buildings.The research used thedesign of a daylight-responsive pavilion, called TetraScript, as a case studyand the article focuses on the generative process and digital fabrication ofthe pavilion. Computation is used in this research as a process rather than atool, which establishes a system of relations, as described.

The general argument was that technology in general, and computationin particular, can allow for customisation and permit architecture to respondto geographical and individual requirements.The documented experiencesuggests that this is possible. It also suggests that in doing so the architectcan reactivate a link with his time by using technology to extend hisabilities.


The use of technology to develop responsive buildings represents achange and an opportunity to develop a more ecological approach to usingtechnology and nature to propose a new, balanced architecture.The processof building the TetraScript pavilion was accomplished without direct funding,and successfully involved different experts, departments, universities, cities,and industries. However, in order to expand and continue this investigation,specific funding may be necessary as the cost of further access totechnology increases.This suggests that the development of sustainablearchitecture using advanced technology might be jeopardised by financialrestrictions.

ACKNOWLEDGEMENTS

The author would like to acknowledge the support of the variousparticipants in the project, including J. Fonseca (digital fabrication),A. Fariaand R. Sousa (structural analysis), and M. Barbosa (automation) from theUniversity of Porto Faculty of Engineering. He would also like to thankindustry partners Sonae Indústria, J&J Teixeira, and Teclena. Gonçalo CastroHenriques is funded by grant SFRH/BD/39034/2007 from Fundação para aCiência e Tecnologia (FCT), Portugal.

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11. Terzidis, Kostas. Algorithmic Architecture,Architectural Press, Oxford, 2006.


Gonçalo Castro Henriques

Technical University of Lisbon Rua Sá Nogueira, Pólo Universitário,Alto Ajuda, 1349-055 Lisboa

[email protected]

tetrascript:a responsive pavilion,from generative design ...quicksilver.be.washington.edu ›...

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