Digital Tectonics

AARHUS SCHOOL OF ARCHITECTURE

RESEARCH PUBLICATIONS

PLATFORM DIGITAL TECTONICS

ARKITEKTSKOLENS FORLAG

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Digital Tectonics © Platform Digital Tectonics / Aarhus School of Architecture Editor: Niels Martin Larsen Graphich layout: OddFischlein Printing: We Produce ISBN: 978-87-909-7937-9 First edition, Aarhus 2014 Published with support from the Østbanegård-fonden Arkitektskolens Forlag Aarhus School of Architecture Nørreport 20 8000 Aarhus C Denmark

Digital Tectonics

P. 04

Platform Digital Tectonics

by Karl Christiansen, Professor, Architect

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Teaching Digital Experimentation

by Asbjørn Søndergaard, Architect, PhD-fellow and Ruben Borup, Architect

P. 16

Architectural Optimisations

by Asbjørn Søndergaard, Architect, PhD-fellow and Karl Christiansen, Professor, Architect

P. 24

Complex Concrete Gridshell

by Niels Martin Larsen, Architect, PhD, Assistant Professor and Ole Egholm Pedersen, Architect, PhD, Assistant Professor

P. 32

To Generate Architecture

by Niels Martin Larsen, Architect, PhD, Assistant Professor

P. 40

Concrete ReBound

by Ole Egholm Pedersen, Architect, PhD, Assistant Professor

P. 48

Genetics

by Karl Christiansen, Professor, Architect

P. 52

Tectonics and Topology Optimisation

by Karl Christiansen, Professor, Architect and Ruben Borup, Architect

FOREWORD

AARHUS SCHOOL OF ARCHITECTURE

Platform Digital Tectonics

Today, the pace of digital developments is frantic. Just a few decades ago the computing power of my PC was inferior to that of the iPhone which, today, every teenager uses to send text messages.

If you do not take care to regularly update programs and apps, you will, in a depressingly short time, fall behind the rest of the world. So if you want to be successful in a larger context you really need to keep up - this also applies to architecture. At the Aarhus School of Architecture we continuously strive to be at the forefront of this development – with regard to research but, of course, also with regard to day-to-day teaching. Recently, our workshops have been equipped with the latest tools of production, including a CNC cutter, a laser cutter, a water jet cutter, and an orange, six-axis industrial robot.

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Roughly speaking, digital tools can today be applied to and assist in architectural projects in two ways: - As an aid for realising the already conceived ideas of the architect and/or to help the architect manage the process leading up to the creation of specific and finished architecture such as, for instance, a house.

- Or as a generative and productive co-player which creates architectural form - form which the architect would not have been able to predict in advance, and which it would simply not have been possible to realise using earlier methods of fabrication.

The latter approach is the approach taken by our platform: Digital Tectonics.

By combining today's enormous computational power with the limitless form potential of the robot it is possible to initiate complex form-generating processes.

The initial ideas behind these processes may have been conceived by architects, yet they subsequently live on and develop inside the 'machinery', which, in the end, consequently has a stake in the result.

However, the whole thing does not run effortlessly by itself.

For one, the architect invariably has to launch an idea for a form, or at least an intended form. Secondly, it is necessary to choose a material which makes the form specific. Thirdly, the architect has to identify a possible tool of fabrication with the potential to initiate a specific architectural form in the selected material.

KARL CHRISTIANSEN

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“Our work does not become truly interesting until the moment our experiments find their way into this world�

By setting up algorithms - rules for what should be possible and what should not be possible in terms of form, the architect initiates, and is hereby given control of, a generative process which takes place between computer and robot, and back and forth again... Iteration after iteration, information is gathered, communicated and developed in the space between planning and realisation, in an amount, and at a rate, which by far exceeds the capacity of the human brain.

The result is an unrivalled coherent relationship between materials, technology and architectural form, which is, in short, tectonic to the maximum. This is precisely what we aim for at Digital Tectonics. Our concern is whether the form which is, finally, given to architecture when it enters the world is well-founded.

And what could be more natural than verifying this form based on the way it was created. This is what happens when tectonics "happen".

We hope this publication and the projects presented herein will give you an impression of the direction we have taken at Digital Tectonics.

As an institution the Aarhus School of Architecture is under an obligation to conduct research and carry out development. We are continuously looking for new approaches. Through our experiments we would like to be a guiding beacon for the world around us. Our work does not become truly interesting until the moment our experiments find their way into this world. For this reason we continuously appeal to producers and, not least, architectural practices to enter into cooperation with us. It is in this way - together - that we should develop and renew architecture.

Happy reading!

Professor, Architect Karl Christiansen

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TEACHING DIGITAL EXPERIMENTATION

AARHUS SCHOOL OF ARCHITECTURE

Teaching Digital Experimentation Asbjørn Søndergaard and Ruben Borup

In September 2011 the Aarhus School of Architecture inaugurated a new focus area. With the opening of Digital Experimentation, the teaching programmes in digital design and fabrication were developed extensively. This was followed by investment in industrial scale digital machining systems, including a robotic laboratory, a large-scale water jet, and equipment for CNC-milling, laser cutting and laser scanning. The build-up of a related knowledge base was implemented through a combination of specialized large-scale workshops encompassing 150-250 students, and smaller, intensive master level workshops. In this way all the School’s 850 students from all levels of the education participated in digital design and fabrication workshops organized by Digital Experimentation within the first semester of its inauguration. The implementation of the target area provided a framework for a series of architectural experiments. The resulting research questions could be divided into three categories: - Which architectural potentials can be unfolded in the interplay between classical craftsmanship traditions, industrial mass manufacturing and custom digital fabrication?

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- Can the development of adaptive, spatial technologies facilitate a new cultural sensitivity?

- What are the architectural implications of the inclusion of tectonic properties in the digital drawing space?

DIGITAL CRAFTSMANSHIP The building industry represents one of the few remaining areas of production which has yet to see pervasive automation. While semi-manufactures, such as brick, timber and concrete, are produced in fully industrialized processes, the processes in which these are assembled into works of architecture are often fully manually controlled. The building industry thus unfolds as a hybrid between craftsmanship traditions, which have essentially remained unchanged since the early middle ages, and the high-tech, mechanised fabrication of for example, modern steel structures.

The development of computer controlled machinery – popularly known as digital fabrication – has facilitated a progressive development in architectural research, pivoting around an explication of architectural potentials offered by

customized, unique fabrication executed on an industrial basis. Teaching and research carried out at institutions such as the Architectural Associations School of Architecture, London, Hochschule für Angewandte Künste Wien, Bartlett School of Architecture, Southern Californian Institute of Architecture, has for years characterized these developments.

The preoccupation and understandable fascination with the new has facilitated an extrapolating focus on the possibilities of purely digital forms of fabrication – which, based on the mechanical logics of the 3d-printer, the robotic manipulator, the laser cutter and the CNC-router, speculates in complex future scenarios for the conditions of architectural creation.

While technological development trends support the realization of these scenarios in the near future, digital research generally evades the question of how these technologies can be combined with today’s existing, low-tech methods of fabrication in architecturally meaningful ways, and what may be derived from such hybridization.

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AARHUS SCHOOL OF ARCHITECTURE

TEACHING DIGITAL EXPERIMENTATION

ASBJØRN SØNDERGAARD AND RUBEN BORUP

RESEARCH PUBLICATIONS

“Which potentials do the coupling of traditional and experimental methods of fabrication offer – and what measures can facilitate such a combination?”

A series of workshops which were part of the launch of Digital Experimentation were themed around this investigation.

Focusing on hybridity, which characterizes actual building processes, they raised the following question: which potentials do the coupling of traditional and experimental methods of fabrication offer – and what measures can facilitate such a combination?

In the workshop ’Architectural Parametrics’ students from the Bachelor degree programme developed a parametric light composition study under the theme ’structure and seriality’. The composition, a light filtering installation in the foyer of the Aarhus School of Architecture, was designed and manufactured over seven days, on the basis of parametric fabrication models. The installation comprised approx. 96% mass manufactured identical panels and posts and approx.

4% laser-cut, unique plugs and wedges.

The production drawings for laser cutting, as well as production lists and dimensions for all mass manufactured components, were directly driven by parametric design models. This way, the structure could be continuously revised with dynamic updates including

production data, material consumption and budgeting, based on which the production of the design could be swiftly executed, once design iterations had been finalized.

The 4% of the installation which consisted of digitally manufactured parts was based on the premise that the individualisation of the angles and lengths of wedges and plugs could be manufactured without any increase in production time. In this way, 812 bespoke elements were manufactured in the same timeframe necessary for the production of 812 copies. The modest quantity of material consumed by this digitally manufactured detailing facilitated a degree of design freedom unobtainable through combinations of standard components.

The individually rotated panels and the global curvature of the structure were thus solely defined by the connections between the standardized elements, which simplified the assembly process.

The structure was manually assembled from one end to another without the aid of drawing material, as the geometry of the composition was entirely determined by the sequence of individualised connection parts. This type of ‘implicit fabrication’ points towards two perspec-

tives. On the one hand, a parameterisation and incorporation of the manufacturing process in the digital drawing space may facilitate a simultaneous and dynamic feedback between architectural effect and production economy; on the other, an economisation of the amount of digital fabrication might allow for a direct coupling with traditional modes of manufacture and craft-based methods.

Given that digital manufacturing is still more expensive than mass production, this points towards the present being a time of transition. But through the addition of limited and economically feasible quantities of digital fabrication, architectural effects unobtainable through the conventional assembly of industrially produced parts can be achieved.

Continuing this strand of thought, the question emerges whether the craftsmanship training required for enrolling in Danish architectural educations in the previous century can today be understood as a type of digital crafting, which, through the build-up of knowledge about existing and future production processes and the capacity to describe these in in digital space, can spur a renewed interest in the technologies and tectonic traditions of the built.

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AARHUS SCHOOL OF ARCHITECTURE

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TEACHING DIGITAL EXPERIMENTATION

ASBJØRN SØNDERGAARD AND RUBEN BORUP

THE ADAPTIVE MACHINE The introduction and cost reduction of various forms of sensor technology – laser scanners, light, proximity and temperature sensors - has enabled a new direction in architectural developments: through the reading of dynamic and complex inputs, and the reaction to these inputs through actuators, servos and electronic devices, a complete loop can now be established between the digital registration of the physical environment, a programmed response

to activities within it, and the processing of this response to physical signals or fabrication. From this a series of question arise. Such questions are: can the incorporation of data from the surrounding space facilitate the emergence of a new sensitivity of architectural systems?

Will such dynamic responses eventually facilitate the development of types of artificial spatial intelligences? Can adaptivity anarchically infiltrate the process of hand-drawing, and, as an agent provocateur, productively corrupt its rationales?

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The workshop ‘Performing Architecture’, held as part of the Master’s degree programme at the Aarhus School of Architecture, in September 2011, by Ruairi Glynn and Richard Roberts of Bartlett School of Architecture and Thomas William Lee from the Aarhus School of Architecture, investigated these implications. In the context of Bispetorv in Aarhus – the most central yet least used plaza of the city – participants were given the task of populating the plaza with artificial, architectural personalities, which

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TEACHING DIGITAL EXPERIMENTATION

AARHUS SCHOOL OF ARCHITECTURE

through mocking, playful engagement with visitors would facilitate a constant and spontaneous reality theatre within the framework of Bispetorv as an urban, scenographic space.

Over seven days, thirteen characters took shape, from sensor-driven lights seeking nighthawks on a walk, to foldable canopies, obligingly sheltering by-passers from the rain and mockingly collapsing again if the disturbance below became too intimidating. The lively appearance of the architectural characters renewed the interest of by-passers in the Bispetorv Plaza.

Whereas directly responsive systems allow for the above dynamics – in more functional contexts this would typically be climatically responsive facades closing or opening for intake of sunlight – the

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sensing of the physical environment also offers perspectives relevant to mechanically static architecture.

As part of the master workshop ‘Cultural Technologies’ a physical-digital process was introduced in which participants through automated photogrammetry procedures, translated digital registration photos of topographically complex landscapes into detailed 3d-models in the course of minutes. The digital representation of the landscape topography framed a series of digital, architectural interventions, in which parametrically adaptive structural systems were embedded in the landscape. The parametric models included the respective fabrication instructions, allowing for a direct translation into laser-cutting of the scale models for further architec-

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“A new representation of reality was constructed through the manual tracing and reiteration of steps” tural studies. The above scaled process represents a principal coupling between physical complexity and digital systems which, through the greater degree of freedom obtained through the dynamics of parametry, can respond and adapt to this difficulty. Such an approach could be established at the building scale which would allow the use of bespoke adaptations based on an industrialized economy of fabrication such as is executed by large-scale CNC machines used in the Danish timber industry.

In such a way the number of options available to the architect expands, outlining perspectives of culturally sensitive technologies which can non-invasively adapt to and be embedded in the real complexity of the physical environment through a sophistication and refinement of the responsiveness.

In the workshop C:R:A:S:H – Computer -Reactive Architectural Systems and Hypermodal Representation, a third potential of adaptive systems was investigated. Through the digitalisation of analogue drawing material generated in architectural analyses of select works

by OMA, the meticulously elaborated diagrams were confronted with auton-

omous and semi-autonomous scripts, which, through part-alien, part-related principles, superimposed new graphical tracks upon the formal material.

A new representation of reality was constructed through the manual tracing and reiteration of steps. This resulted in an accumulation of iterations based on feedback between the original and new material which created surprising new perspectives for reading the work.

Enriched with contradictory yet overlapping narratives, the material was translated into three dimensional constructs, to provide impetus for the generation of individual projects.

DIGITAL TECTONICS The possibility to digitally simulate material properties has expanded the perspectives for the structural understanding of architectural systems. Through methods such as topology optimization, it is possible to develop advanced, structural morphologies with a performance largely superior to those enabled by empirical design methods. Complementary to this, numerical descriptions of physical conditions allow for a quantification and concretisation of abstract relations, such

as the feasibility of a given shape for certain modes of production, or economic relations between geometries and their manufacturability.

These changes point towards a progression from the use of digital technology to represent form to digital tectonics, in which computer models and three dimensional descriptions of architecture which describe form also embed tectonic relations between material properties, production constraints and geometry.

In continuation of this perspective, a new direction for a digital culture can be seen, a direction in which matter and the description of matter coincide to a higher degree. As a consequence, the need for a comprehensive investigation of the architectural implications of these developments surfaces as the architectural profession, through the proliferation of digital tectonic systems, finds its role reinterpreted on new premises.

In the master workshop ’Architectural Skins’ architect Daniel Piker of the Architectural Associations School of Architecture challenged the understanding of structural descriptions of materials by including meta-properties using his Grasshopper extension, Kangaroo.

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TEACHING DIGITAL EXPERIMENTATION

AARHUS SCHOOL OF ARCHITECTURE

Piker argues that whereas classical CAE software is able to precisely describe aspects of structural performance, what is more relevant is the relationship linking geometry to feasibility and expense.

Through the definition of dynamic optimisations in which surfaces or components are optimised to meet production constraints, such as, for instance, the equilaterality of edges, a type of synthetic behaviour arises, which in the digital modelling space is experienced as quasi-physical material properties, which deflect, curl and stretch in dynamic relation to the manipulations of the user. This way the relation between geometry and fabrication becomes a dynamic driver for a new digital materiality, which is related to, yet deviates from, physical material properties, hereby embodying or materialising abstract, production economy logics in the architectural shape.

In the course, ’Flux Topologies’ held by Asbjørn Søndergaard and Jelle Feringa, manager of the Hypebody robotic laboratory at TU Delft, the issues referred to above were investigated from a complementary perspective. Research in topology optimisation of concrete

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structures indicated the possibility for vast reductions in the use of material, but resulted in advanced morphologies that challenge current construction and production methods. Robotic hot-wire cutting of expanded polystyrene represents a cost-effective and fast method for the production of advanced moulds, assuming single or double ruled input geometry. In the field of flux topologies, Master’s degree students generated topologically optimized structures, subsequently rationalizing these to ruled geometries and cutting trajectories for an ABB IRB 2600 robotic manipulator.

The process demonstrated the possibility of achieving structurally efficient designs through topological optimisation. When translated into hyperbolic paraboloids and single ruled surfaces these can be cost-effectively produced by introducing robotic hot-wire cutting.

“A new direction for a digital culture can be seen, a direction in which matter and the description of matter coincide to a higher degree”

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ARCHITECTURAL OPTIMISATIONS

AARHUS SCHOOL OF ARCHITECTURE

Architectural Optimisations Asbjørn Søndergaard and Karl Christiansen

In 2007 the Aarhus School of Architecture embarked on the Unikabeton project, a three year inter-disciplinary research project investigating topology optimisation of concrete structures and robotic CNC-milling of EPS moulds. The project spanned a number of comparative studies, resulting in the production of a full scale prototype structure. The comparative studies yielded two primary findings: that topology optimisation may reduce material consumption with up to 70% in comparison to standard, massive equivalent structures, while respecting normative structural requirements; and that optimisation results in a new, tectonic language, rendering the trajectories of forces visible to the observer.

Topology optimisation is a process, in which a volume – the so-called design space – is defined, in which virtual material is subsequently redistributed.

In optimisation for maximum stiffness, an optimal distribution of material is reached through the process, resulting in the highest possible rigidity with the given amount of material. The reductions in material consumption hereby achieved, imply reductions in the environmental cost of the related construction activity: as the global cement industry

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is globally accountable for 5% of the total, annual C02-emissions (double the amount emitted by the global air traffic by comparison), a reduction in material consumption of the above quantities could potentially contribute to significant reductions of these emissions.

The result of the optimisation process is, however, morphologically complex, and thus difficult to manufacture using existing production methods. Digital fabrication allows for the production of advanced geometries under industrial conditions, with clearly predictable precision and time consumption through purely machinic processes. A main goal of Unikabeton was to investigate the construction of a topologically optimised concrete structure using robotic CNC-milling.

To meet this target, a prototype structure of 12 x 6 x 3.3 meter was designed and optimised. To explore the capacity of the optimisation for handling particularly difficult conditions, which would have been difficult or even impossible to achieve through empirical design methods, a challenging case was chosen: an asymmetrical, doubly curved slab structure, simply supported on 3 columns.

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"Optimisation results in a new, tectonic language, rendering the trajectories of forces visible to the observer"

To ensure dewatering of the top surface, the slab was designed as a minimal surface, suspended between a rounded border and three lowered points at the column. The resulting shape was loaded for dead load and snow load, and optimised for a 75% reduction of material.

The optimisation result was subsequently remodelled, and a negative geometry cut in blocks of polystyrene was assembled on traditional in situ scaffolding on the building site.

The optimisation presupposed a light fibre concrete, which was theoretically capable of sustaining its loads in an unreinforced condition. However, project requirements necessitated the use of self-compacting concrete with ordinary tensile properties, requiring the use of conventional reinforcement. The complex shape necessitated a comprehensive and complex reinforcement design, involving time consuming manual production of the reinforcement rebars and rods.

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The project concluded that topology optimisation as an architectural design tool results in the development of new, structural shapes, which through advanced morphologies significantly reduce material consumption; and that such structures can be realised in practice in combinations with CNC-milled EPS casting moulds using conventional scaffolding. However, while CNC-milling is predictable with regard to time-consumption and production precision, it is a highly time consuming process which is infeasible for large scale fabrication. In addition, the need for bespoke reinforcement represents a significant challenge, requiring the development of alternative solutions.

These challenges are being addressed by the on-going pilot-project, Opticut.

Through several years of research by Prof. Karl Christiansen and Associate Prof. Anders Gammelgaard, manual hotwire cutting of EPS moulds has been

ASBJØRN SØNDERGAARD AND KARL CHRISTIANSEN

explored for production of concrete panels with individualised surface geometries. The method has shown great potential for time-effective production of single ruled surfaces. Opticut explores robotically driven hotwire cutting, which facilitate cutting procedures with a precision which cannot be achieved by manual methods. The pilot project investigates the approximation of optimised topologies through computational construction methods for single and double ruled surfaces. Complementary to this, the reinforcement challenge is sought reduced by utilising high performance concrete, which due to its high tensile strength simplifies the demands on the reinforced sections. Furthermore, the utilisation of ruled geometry eliminates the need for curved reinforcement bars, thus greatly simplifying production.

The project is conducted as a collaboration between the Aarhus School of Architecture and industry partners Hi-

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con A/S, Hyperbody Robotic Laboratory, TU-Delft, Odico Formwork Robotics, Confac A/S and Søren Jensen Consulting Engineers A/S.

PERSPECTIVES The application of topology optimisation as an architectural design tool points to a number of perspectives for the architectural design process and for understanding the role of architectural structures.

The topology optimisation process (TO) is an autonomous form-finding process, which transfers direct control over form from the architect to the computational process. As the complexity of TO surpasses what can be empirically achieved, the process holds a significant moment of unpredictability. While direct design control is abandoned, a form of indirect control is maintained, through which changes in the optimisation setup – the shape of the design space, the position-

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AARHUS SCHOOL OF ARCHITECTURE

ARCHITECTURAL OPTIMISATIONS

“While direct design control is abandoned, a form of indirect control is maintained”

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ASBJØRN SØNDERGAARD AND KARL CHRISTIANSEN

ing of support, etc. – is reconfigured, until architecturally feasible results are achieved. This points towards potential benefits from incorporating TO at an early stage in the design phase, where a conceptual freedom for changing conditions remains, hereby ensuring a possibility for incorporating the expressiveness of the optimisation results in the overall architectural design intent.

Furthermore, TO points towards a break with traditional typologies. Where the engineering tradition traditionally based solutions on existing typologies and parts, and, based on this, built up a global system, optimisation results represent free typologies, which transcend classical typification. This condition enables the exploration of a new generation of structures characterised by gradient transitions and double functions, a

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form of transitional structures. Where architectural rationality has historically been connected with a notion of carthesian geometry and orthogonality, TO surprisingly indicates that higher forms of rationality is found in morphologically advanced, biomorphic geometries. While current fabrication technologies are still lacking behind in matching this rationality with the conditions for time-efficiency as mass production of standardized elements, technological development trends indicate a coming change in these relations, under which the economisation of robotic production processes, the scale-up of additive manufacturing, as well as an increase in the application of digital fabrication in architectural project development, may instil a disruptive and permanent transformation of the fundamental conditions for architectural construction.

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AARHUS SCHOOL OF ARCHITECTURE

Complex Concrete Gridshell Niels Martin Larsen and Ole Egholm Pedersen

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COMPLEX CONCRETE GRIDSHELL

NIELS MARTIN LARSEN AND OLE EGHOLM PEDERSEN

This article presents the development and testing of a design method for complex concrete structures, dealing with both physical and digital constraints.

In this case the basis/starting point is form-finding. The most famous example of the use of analogue form-finding methods is Antoni Gaudi’s hanging chain models of the Colonia Güell (figure 1).

Gaudi realised that in the case of a three-dimensional vault structure, it was necessary to use three-dimensional models to generate the optimal shapes.

By hanging small sandbags from strings, he made large models for simulating an optimised compression structure. The sandbags were weighed so as to represent the loads on the structure. Gaudi experimented with different methods for transferring the shape of the complex models through drawings, photography and by covering them with cloth in order to extract their form. The use of three-dimensional hanging chain models is the basis for digital methods for simulating dynamic relaxation

RESEARCH BACKGROUND The prerequisites for the project consisted mainly of two parts: a viable method based on concrete casting in PTEG sheet was previously developed

by Ole E. Pedersen (described in detail elsewhere in this volume) and forms the basis for the casting techniques that are used in the method described here.

The second part is a computer program for simulating dynamic relaxation, developed by Dave Pigram and Iain Maxwell.

The challenge was to develop a method that combined both techniques, and to test the method by producing a fullscale concrete structure.

In this case, the form generation has been coupled to state-of-the-art digital production technology. The method thus demonstrates the possibility of realising a structure of advanced geometry through component-based construction. Furthermore, the project suggests new sustainable techniques for casting distinct concrete elements.

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Fig. 1

“The idea was to integrate the processes of production and method development, in order to embed aspects of realisation in the form-generation method”

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COMPLEX CONCRETE GRIDSHELL

AARHUS SCHOOL OF ARCHITECTURE

Fig. 2

Fig. 3

Fig. 4

Fig. 5 Fig. 5

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NIELS MARTIN LARSEN AND OLE EGHOLM PEDERSEN

The idea was to integrate the processes of production and method development, in order to embed aspects of realisation in the form-generation method.

In particular with respect to the digital tools necessary for generating drawings and information for digital production.

Besides the researchers and consultants, a group consisting of students from Sydney and Aarhus participated in the development and realisation of the case study pavilions which were built to demonstrate the design method.

DYNAMIC RELAXATION Dynamic relaxation is the process of simulating gravity. A two dimensional drawing of a mesh serves as input. Then, through hundreds of iterations, the elements of the mesh change their geometry to negotiate forces applied by the dynamic relaxation algorithm until arriving at an equilibrium state (figure 2). In this state, the structure is in pure tension, or in pure compression, depending on the setting of the gravitational force. The three-dimensional mesh is then exported to a 3D modelling software (Rhinoceros 5.0).

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Fig. 7

Fig. 8

FROM MESH TO GEOMETRY In order to translate the mesh into a series of concrete elements, it is necessary to define the component geometry (figure 3). Concrete can take complex forms; this makes it practical to keep the complex joints where three lines meet in the centre of a component, and let two components meet on the line between nodes. It follows that each component would be Y-shaped, with variable arm lengths and angles and would meet the neighbouring element at an angle to deal with the non-planar nature of the hexagons (figure 4). The geometry is then developed into unique volumetric components via custom written algorithms, executed as a script in Rhinoceros. In the same script, input for the manufacturing process is generated. This included scoring lines for folding, rivet holes, the engraving of a unique number (figure 5) and information which was used to generate 110 unique cutting templates (figure 6). Once cut, the templates were folded, joined and concrete was poured (figures 7 and 8). The code is configured so it reflects the design intents of the component geometry and the requirements of

the production process. For instance, it is able to distinguish between regular and base components, generating a flat base for the latter (figure 9).

Laser cutting is used for producing discrete templates for concrete casting.

The mould material is PETG plastic, which is easily recycled through melting at 260 ยบC, evaporating only CO2 and water. The PETG sheet is typically 1 mm thick, has a high degree of deformation, and must be reinforced by folds by triangulating large areas and limiting the area of planar surfaces. These factors contribute to the aesthetic characteristics of the method.

Given the relative thinness of the elements, it is extremely important that the constructed structure matches the computationally found form so that all load paths remain within the sectional profile.

Additionally, as is typical in non-Catalan vaults, the structure is not stable in an incomplete form. Therefore, it is necessary to use formwork to ensure the exact positioning of every component and to support them during assembly. Like the pre-cast components, each scaffolding element is unique.

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COMPLEX CONCRETE GRIDSHELL

AARHUS SCHOOL OF ARCHITECTURE

Fig. 10

Fig. 11

Fig. 12

ASSEMBLY Given the relative thinness of the elements used in this method, it is extremely important that the final construction matches the computationally found form so that all load paths remain within the sectional profile. Additionally, as is typical in non-Catalan vaults, the structure is not stable in an incomplete form.

ometry made assembly impossible. Component placement on the scaffolding was directed by unique identifiers, matching a component’s arm to the corresponding arm on the neighbouring component.

The Playvault Pavilion (figure 14) was an attempt to integrate some degree of usability with respect to construction at a Kindergarten playground. The project was carried out as a workshop, led by Ole E. Pedersen, involving 40 students over a period of two weeks at the Royal Academy in Copenhagen and had two purposes: to test the method in an industrial production outside the laboratory and to explore the potentials for the method to deal with a more complex overall form. A new version of the dynamic relaxation algorithm was implemented as a Grasshopper/Python component in Rhinoceros by Niels Martin Larsen. This was in order to keep the digital development of geometry within a single piece of software. This allowed first year students to quickly learn the workflow of drawing a mesh, performing dynamic relaxations, and component generation. This enabled many designs to be quickly proposed and evaluated by the participating engineers. The original algorithm is a simplified version of a spring system, which does not include velocity as part of the calculation. The Grasshopper implemented version uses a Velocity Verlet calculation method, thereby simulating a physical spring system.

As such it is necessary to use a scaffolding to ensure the exact positioning of every component and to support them during assembly (figure 10). Like the pre-cast components, each scaffolding element is unique. The 3D component model was used for extracting the geometry of the falsework and for positioning the individual components during the assembly. The scaffolding was produced from cardboard, laser cut and assembled, first into triangular tubes, then into larger clusters forming hexagonal geometries, reflecting the plan of the concrete structure. The function of the scaffold is both to support the structure during construction and to ensure the exact positioning of the components, the latter aspect being the most important, since very small deviations from the spatial ge-

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CASE STUDIES Three constructed case studies contributed to the development and testing of this method.

The worst case prototype (figure 11) was a deliberate test of a design that had known insufficiencies and thus gave a better understanding of the limitations of the method and the forces which needed to be handled.

The Concrete Gridshell Pavilion (figures 12 and 13) incorporated all of the lessons learned from the ‘worst-case’ prototype.

It was used as part of the cultural event ‘Kulturnat Aarhus’. The structure was designed to include the capability of being disassembled. It was this requirement that made the use of many, smaller components the most suitable solution, and which led to the use of mechanical (as opposed to cast) joints between them.

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Base component with a flat bottom

Fig. 9

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AARHUS SCHOOL OF ARCHITECTURE

Fig. 13

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COMPLEX CONCRETE GRIDSHELL

NIELS MARTIN LARSEN AND OLE EGHOLM PEDERSEN

CONCLUSION The case study pavilions were all constructed in a very short time, at a low cost using relatively unskilled labour.

This demonstrates that the integration of algorithmic form-finding techniques, CNC fabrication workflows and the use of innovative PETG folded mould techniques enable the practical realisation of freeform funicular structures in pre-cast concrete. While the pavilion was a success in terms of precision and structural performance, Case Study 3 demonstrated that the proposed method can be utilised to generate more complex forms. The project demonstrates how digital technologies can be used to gain larger variation and complexity in the design and realisation of an architectural

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construction. The self-organisational form-generation method was successful in terms of arriving at an optimised structural shape within a limited time span. The method will be further developed through future case studies at Digital Tectonics, and in collaboration with our external partners.

Method: Dave Pigram, Ole E. Pedersen, Niels M. Larsen Consultants: Jacob Christensen, Ronni L. Madsen Tutors: Stefan R. Nors, Jon K.E. Andersen, Jacob L.E.Christensen The case studies were developed and realised with the aid of students from Aarhus School of Architecture, University of Technology in Sydney and The Royal Danish Academy of Fine Arts.

Fig. 14

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AARHUS SCHOOL OF ARCHITECTURE

TO GENERATE ARCHITECTURE

To Generate Architecture Niels Martin Larsen

Fig. 1

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NIELS MARTIN LARSEN

Generative techniques can have relevance to different levels of architectural design. First, they allow a much higher degree of complexity in design solutions.

Second, various types of optimisation is possible, and third, the techniques can lead the way to a more direct integration of material properties and production constraints into the design process.

In the following I will discuss these potentials and illustrate them through examples from my own research.

The term generative techniques here refers to algorithmic methods for generating architectural geometry. Methods for which the geometry is not explicitly defined, such as through 3D modelling or CAD drawing, but which are defined through a set of rules and conditions which then guide a process of ‘growing’ the geometry. Many of these methods can be described as scripting, which usually refers to extended customisation of design tools. Most of the examples shown here goes one step further and rely on free-standing computer programs that are developed as part of the design process. In the following examples, the systems are nonlinear, which means that there is an indirect connection between the input parameters, the rules that guide the system, and the result. This

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can be seen as a disadvantage, since the result is not completely predictable and controllable, but it also allows a variety of parameters to be negotiated as part of the form-generating process. In addition, this property opens a field of, perhaps unexpected, outcomes which can affect the design process positively.

The algorithmic methods allow designers to work with much larger amounts of information and complexity, thereby extending the field of possible solutions.

Complexity can be created in many ways, but the strength of the generative systems is that the outcomes by nature have an underlying mathematical logic.

This makes it possible to extract all necessary information needed for realisation. This differs from most architectural projects, even when they are realised through use of advanced computer software. In most cases the original design is developed without this inner logic, for instance through use of analogue models or through explicit 3D modelling without geometric constraints. Subsequently, a ‘cleaning’ process is needed to extract the information necessary for producing realisable geometry. Through generating the geometry algorithmically, it is possible to ensure that the produced geometry is consistent, and realisable.

This property points back to the initial phases of the design process, allowing the designer to explore a wide field of complex solutions.

Complexity is not necessarily a goal in itself, but the larger the amount of complexity the designer can manage, the larger the scope of possible solutions for a specific problem will be. Realisation of more complex solutions is underpinned by the proliferation of digital production facilities within the building industry.

If algorithmic design expands the field of architectural expression, it only makes sense if possibilities for actually realising the design simultaneously exist.

CNC-milling machinery and robots are gradually becoming standard production facilities, thereby allowing architects to base their designs on the properties of these technologies. Production constraints can then be embedded into tailored algorithms, so the formgenerating process leads to designs that suit the actual production process.

The Complex Gridshell, described in the previous chapter demonstrates how it is possible to establish a cyclic development process, where knowledge from 1:1 experimentation with production is incorporated in the digital tools that generate the geometry.

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TO GENERATE ARCHITECTURE

AARHUS SCHOOL OF ARCHITECTURE

Optimisation is an important potential of the generative techniques. This could be directed towards structure, climate, material consumption, the realisation process and other problem types. This optimisation is not necessarily restricted to adjust to a single parameter, but can be the result of negotiation between various weighted parameters and design intents. For instance, if a generative system for generating a façade pattern is developed, this system could negotiate between the amount of solar radiation that enters the building and the size of the views from the interior spaces to the outside. An example of the shape and size of the openings adjusting to the building’s orientation is shown in Figure 2.

Another aspect of using generative techniques is more connected to the fact that they are inherently digital, and therefore can be easily communicated between different actors in the project development process. This can lead the way to a more direct integration of material properties and production constraints in the design process. The digital exchange of information allows engineers and manufacturers to tap into the same pond of information, rather than having to build up individual pools.

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This again supports a process where constraints related to realisation of the project can be integrated in the initial design phases, thereby leading to a more holistic solution.

During the development of my PhD research project, I studied how a series of algorithms can be used as part of the architectural design process. In the following I will go through some method examples related to some of the issues mentioned above. The subjects and the methods are unfolded in depth in the thesis: Generative algorithmic techniques for architectural design.

SELF-ORGANISATION AND EMERGENCE Many recent projects characterised by complex geometry, particularly those with curved or doubly curved structures, have been realised through the use of algorithmic tools. These are often socalled ‘parametric tools’ that allow the individual building components to adjust in measures and proportions, depending on their position in the overall structure.

Usually, the components are related to a pre-defined surface. As a rule, the order of and the relations between components are also pre-defined. If we let go

of the latter constraint, the possibility of engaging with self-organisation emerges.

In this situation a more complex negotiation between parameters and components can be established. There is no longer a direct relation between input and output, but rather a non-linear system. An advantage of this approach is that we can get past the underlying grid needed for a standard parametric system, and allow the design elements to more freely find their optimal configuration. The facade pattern in Figure 2 is an example of this. While the initial distribution of the pattern is completely random, the rules that control the system allow it to self-organise into a consistent pattern.

A well-ordered façade pattern emerges. The example shows how the term emergence, usually related to biology, can be linked with the way architects seek to create wholeness through the way building components are assembled.

Fundamentally, building materials are mounted to form a building, but also on a more aesthetic level, architects seek to establish a wholeness that can affect our senses.

In this case, the pattern is still constrained to the surface on which it is drawn, a NURBS surface. By connecting

NIELS MARTIN LARSEN

RESEARCH PUBLICATIONS

“Complexity is not necessarily a goal in itself, but the larger the amount of complexity the designer can manage, the larger the scope of possible solutions for a specific problem will be” Fig. 2

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AARHUS SCHOOL OF ARCHITECTURE

Fig. 4

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TO GENERATE ARCHITECTURE

NIELS MARTIN LARSEN

RESEARCH PUBLICATIONS

Fig. 3

patterns on two corresponding surfaces oriented inwards and outwards, respectively, the result of the procedure can be described as a ‘deep’ pattern. The pattern is basically constructed in two separate steps. First, a number of centre points are distributed on the surface.

Each point ‘detects’ if any points are within its private zone and moves away from these. This simple rule is sufficient to make sure that the centres distribute evenly. The second part of the system is the drawing of the Bezier curves.

First they are constructed around the centre, and then an expansion process is carried out, letting the curves fill the surface, depending on predefined distance parameters. These parameters can be differentiated across the surface.

Depending on the orientation of the local part of the surface, the openings become larger or smaller. Also the distances between the openings adjust to increase the differentiation. In other words, the pattern-forming parameters are linked with local conditions, and begin to demonstrate the system’s adaptability.

A challenge related to emergence has to do with topology. How can elements on a lower level arrive at well-defined complex topology on a higher level

without a predefined guiding structure?

This question is explored through the method Branching Topologies. Here, the algorithm for drawing Bezier curves is expanded to allow the curves to join and separate in a sequence of frames, as seen in Figure 3. The frames are extracted with a certain interval from a series of 2-3000 thousand algorithmic states.

The frames are read as section drawings and post-processed using a so-called isosurfacing algorithm, to finally produce a complex mesh, such as the one shown in Figure 4. This method is relatively complex, but also limited in use, particularly due to its directional character.

As such, the method is not completely three-dimensional in its functionality.

However, these constraints can also be seen as advantages. As used in the example, where a type of column structure is generated, the algorithm ensures that all parts of the structure are connected, and that they are directly rooted in the ground. At the same time, it is possible to control material use through dynamic changing of the cross-sectional area of each coloured area. It is possible to adjust the algorithm to make certain parts more or less massive, which also affects the character of the output.

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TO GENERATE ARCHITECTURE

AARHUS SCHOOL OF ARCHITECTURE

Fig. 5

Fig. 6

SELF-ORGANISED TOPOLOGY To explore the potential of self-organisation in relation to topology one step further, a study of agent-based models provided a basis for developing another method, the Self-organising Surface.

Here a surface is formed from a completely chaotic point cloud. Whereas Branching Topologies worked through a sequence of sections, this method is entirely three-dimensional.

For the Self-organising Surface method, the goal is to arrive at a consistent topology. The system is initiated as a randomly distributed point cloud, consisting of points that may eventually end up representing nodes in the final topology. Each point in the cloud is defined as an agent with certain properties. In the examples, the agents merely seek to establish connections to neighbouring agents in such a way that they together form a consistent surface topology. See Figure 6. More advanced configurations are also tested in order to study the geometric potential of the method. Figure 5 shows how the self-organising method is capable of resolving a relatively complex situation where three tubes meet in an undefined junction. In future developments the behaviour of the agents can be expanded to take other parameters into account. This could be manufacturing constraints, structural properties or contextual parameters, such as light and orientation. In this way, the system can generate a solution where the geometric result represents a negotiation between all these parameters.

Agent-based models are used in many different fields of science. Examples include simulations of ant interaction, bird flocks, financial markets and the nervous system. The principle is that each entity of the system is equipped with an individual set of rules and ‘aspirations’, and that the interactions between the entities lead to an emergent pattern.

This pattern cannot be concluded directly from the individual agent’s perspective, but only from the behaviour of the whole system. Figure 1 shows how an agent-based flocking algorithm can be translated into a system that generates three-dimensional geometry.

The method was built from a script by Roland Snooks and developed in collaboration with architect Morten Bülow.

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CONTEXTUAL PARAMETERS Another line of research that seeks to negotiate parameters of the form-generating process is the Solar DLA Wall. Here, the known algorithmic principle, DiffusionLimited Aggregation (DLA), is linked with an attempt to shield against solar radiation. The DLA algorithm generates characteristic patterns that correspond to the way dendrites grow in nature. An example of a natural dendrite is shown in Figure 7. The basic DLA algorithm and the geometric principle derive from a workshop, directed by Rupert Soar, Petra Jennings and Rupert Soar at the conference Smart Geometry 2011. The system has subsequently been developed to be capable of balancing the ‘free’ pattern formation, controlled by the DLA, with a sun path simulation engine that measures the pattern’s capability of shielding predefined points against direct sunlight.

This allows generation of a ‘deep’ screen that protects specific areas behind the screen against solar radiation. The degree of protection is adjusted to fit the specific situation. The system is fundamentally stochastic, but the tendency to grow protecting cells in certain zones of the screen is controllable.

NIELS MARTIN LARSEN

RESEARCH PUBLICATIONS

Fig. 7

Fig. 9

An experiment with facade systems for hospitals has been carried out in collaboration with PhD candidate Carlo Volf. The aim was to test ways to avoid overheating of the building, while maintaining satisfactory natural light conditions. Through use of 3D printed models and time-lapse photography the system was studied through physical models on the roof of Rigshospitalet in Copenhagen (one of Denmark's largest hospitals employing a staff of 8,000). Figure 8 shows three images from the recorded sequence. The experiment demonstrated that the algorithmic pattern was a fully viable method for adjusting the amount of sunlight, and that the light was softened by reflections in the three-dimensional solar screen wall. However, it was recognised that there are still too high contrasts between the covered parts of the faรงade and the open parts, when looking from inside towards the exterior, as known from more two-dimensional faรงade screens. This problem will be examined in future experiments, based on other types of algorithmic patterns.

ALGORITHMIC TOOLS IN ARCHITECTURE Many architectural practices are currently using advanced customised tools to control various types of complex projects.

The tools are in many cases being used for solving complex geometric problems that would be more time-consuming without these advanced digital tools. You could say that the existence of the digital tools allows the designers to propose solutions that demand control of this amount of information and complexity, but usually the tools are not directly part of the form-generating process in the early design phases. This means that some of the potential of the techniques described here remain unexplored. One is the possibility to integrate several parameters, such as constraints, in the manufacturing process, or contextual properties, in the form-generation process. Another is how algorithmic techniques may allow the use of more complex patterns, while maintaining geometric control of the outcome.

These potentials and many others are waiting to be explored in realised architectural projects, and this is part of the agenda of the Digital Tectonics platform.

Fig. 8

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AARHUS SCHOOL OF ARCHITECTURE

Concrete ReBound Ole Egholm Pedersen

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CONCRETE REBOUND

OLE EGHOLM PEDERSEN

RESEARCH PUBLICATIONS

Fig. 1

Fig. 2

INTRODUCTION Contemporary techniques for concrete casting in an architectural context are challenged by demands for increased individualisation of our built environment and for reductions in the use of resources and in waste generation. In recent years, new production technologies and strategies that break with the industrial paradigm of standardisation have been put forward.

By following this trajectory, the notion of Digital Tectonics is a particularly interesting notion as it foresees a collapse of oppositions, namely that of the digital as abstract representation which is opposed to the tectonic which deals with physical construction and materiality.

This collapse marks a shift from an emphasis on visual composition, as known from the Classicistic period, towards an emphasis on structure, as seen in the Gothic period. In other words, digital tectonics is a matter of structure. The architect becomes a controller of the digital processes by which dynamic relations between material properties and the flow of forces generate architectural form. The role of the architect is then to steer these processes, in close collaboration with the structural engineer, so that tectonic architecture may emerge.

The Big Belt house by Massie Architecture is an example of this: a concrete house made up of concrete cast in mass-customised moulds, creating a building that is integrated in the rolling hills of Montana (figures 1 and 2).

The development is carried forward by computers and digital fabrication, but only few techniques are put to use in the production of building components.

The question arises if it is possible to enhance existing techniques or develop new concrete casting techniques which allow for individualisation and resource optimisation, while matching or enhancing the qualities found in existing, repetitive concrete casting techniques?

CONCRETE TECTONICS Concrete casting is the imprint of a mould, and implies two processes: namely the process of casting concrete and the subsequent assembly of concrete structure - or concrete tectonics, but also the actual making of the mould, the mould tectonics.

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CONCRETE REBOUND

AARHUS SCHOOL OF ARCHITECTURE

FORM

MATERIAL

MOULD TECTONICS

MATERIAL

TECHNIQUE CONCRETE TECTONICS

FORM

Fig. 3

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OLE EGHOLM PEDERSEN

RESEARCH PUBLICATIONS

Fig. 4

Fig. 5

CONCRETE TECTONICS Casting and assembly involve the use of the material concrete and a technique: concrete casting. It is the application of the casting technique to the concrete material, which creates form. Following the concept of tectonics (the idea that every material points towards certain techniques and vice versa) allows us to express concrete tectonics by means of a triangle (figure 3).

AMORPHOUS MOULDS IN POLYSTYRENE When looking into mould tectonics, the first question to ask is this: what material is able to deal with both the immense pressure and the inherent amorphousness of concrete at the same time? One obvious answer is EPS (Expanded Polystyrene). There are three good reasons for choosing EPS as a mould material.

First, EPS is a lightweight material which can still cope with the huge pressure of poured concrete without deforming. And second, EPS is made up of small beads, thus resembling the amorphousness of concrete. Third, because of its low density, normally around 40 gram per litre, it is easy to manipulate EPS with tools.

When milling or cutting a material, a high material density increases the need for tools of greater strength while limiting the working speed. Consequently, lower material density results in higher cutting or milling speeds. EPS has been used in several contemporary projects where non-linear concrete casting was desired, a case in point being the Big Belt House.

MOULD TECTONICS In this triangle, the technique is interesting because it involves the making of the mould. Which for its own part involves a geometric form made from a material that has been subjected to a technique that is, another triangle, which we might call the mould tectonics triangle.

In the following, I will address mould tectonics as a method for investigating how logical connections between mould material and technique may be proposed, given the current technological situation.

The technique used in the Big Belt House could be referred to as sculpturing – form is generated by removing material from a solid. While the use of this technique is intriguing due to the high degree or formal freedom, it is also problematic.

The technique is slow, and milling EPS results in a problematic surface because the carving or cutting process exposes the porous internal structure of EPS, allowing cement to seep through it, which creates a rough surface and makes dismantling the mould very difficult.

Also, the drill bit leaves traces which may be desirable in some cases, but not in others (figure 4). One may argue that the process of CNC milling EPS into double curved forms is not tectonic. This statement may seem academic, but the upshot is that making CNC milled moulds is time consuming, which is why the technique has not found a place in the competitive, economy-driven environment of the concrete industry.

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CONCRETE REBOUND

AARHUS SCHOOL OF ARCHITECTURE

Fig. 6

Fig. 7

Fig. 8

EPS – UNDER PRESSURE So, what would constitute a tectonic use of EPS? Returning to the material properties of EPS, the potential amorphousness of EPS is important – like concrete it can take any form, which is evident from its use in the packaging industry. (figure 5).

Interestingly, these forms are the result of casting, not milling, EPS.

coffee cups, etc. is cast in more complex forms and is given the highly tactile and closed surface described above. A common property of the casting process is that it is industrialised and yields repetitive forms in EPS, rendering current EPS casting techniques useless for unfolding concrete’s potential to take up varying forms in a mass-customised fabrication environment.

controlled by 12 push-rods, was added to the cage, forcing the EPS to separate into two elements upon casting (figures 8 and 9).

The second potential is the surface property of EPS. When the EPS is cast, the beads fuse to form a closed surface without gaps (figure 6). This eliminates a problematic aspect of cutting or milling EPS: that cement seeps through the surface, complicating de-moulding and ruining the surface, unless it is covered in plastic, resin, or treated with retarder.

With EPS, as with concrete, it is this process which gives rise to form. When casting EPS for use as insulation it is cast in a rectangular casting chamber several meters in width and height. Traditionally, it is these blocks that are subsequently hot-wire cut or CNC milled to form moulds for concrete casting, as is the case with the Big Belt House. EPS used as protective casing for consumer products,

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So what if the industrialised EPS casting technique was modified to allow for amorphous forms rather than rectangular blocks? To test the hypothesis, a pressure chamber for EPS casting and a steam boiler was designed and built (figure 7).

The chamber was dimensioned to represent the pressure chamber at the EPS production facility ‘SCA flamingo’ in the scale of 1:5. Elements cast in the chamber have a dimension of 624 x 300 x 120 mm, and correspond to buildingscale elements with a dimension of 3120 x 1500 x 600 mm.

Inside the chamber, a cage for the EPS beads was made. A flexible membrane,

The EPS casting process takes about 10 minutes, allowing for high output rates.

Then the EPS block is removed, the two EPS technique blocks are pulled apart and placed in an outer retaining box, creating an amorphous cavity in which concrete is poured (figure 10). If one imagines the technique upscaled to pressure chambers currently used in industry, it would be possible to produce amorphous concrete elements of up to 3 x 1.5 meters in size.

FURTHER DEVELOPMENT The primary area of development would include the adaptation of the flexible membrane to the full-scale casting chamber at the EPS production facility, and upgrading the manual push-rods controlling the membrane to digitally controlled ones linked to a digital model. The elements produced would be tied together in a fashion similar to how it is done today, but would allow for double-curved concrete constructions (figure 11).

OLE EGHOLM PEDERSEN

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Double-curved EPS moulds cast in scale 1:5

Fig. 9

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CONCRETE REBOUND

AARHUS SCHOOL OF ARCHITECTURE

Fig. 10

Fig. 11

FOLD Free from the difficulties of controlling the technology used for casting EPS, the Fold casting technique uses a more readily available technology: laser cutting.

So the question we should ask is how the logic of the laser cutter might be utilised for mould making? The technique that comes to mind is folding: laser cutting is capable of cutting complex and unique shapes in flat sheets of material with a high degree of precision, yielding complex forms that may subsequently be folded, or joined, into three dimensional moulds. In fact, bending or folding is the simplest way to create a three-dimensional volume from a two-dimensional surface. A bending test of various plastic types reveals that PETG plastics are suitable: it is somewhat ductile, whereas other plastics are brittle and snap. Thin sheets can be bent along a bevelled edge, thicker PETG can be bent using a heat gun, provided dashed fold lines have been made with the lasercutter.

Fig. 12

Fig. 13

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OLE EGHOLM PEDERSEN

RESEARCH PUBLICATIONS

Fig. 14

The individual concrete elements are defined digitally by means of a set of parameters, rather than drawn by hand.

The process involves generating a system which guides the placement of each concrete component in a 3D model, subsequently generating the component on the basis of the information given from the system, and, finally, unrolling the component geometry into a casting mould (figures 12 and 13).

Having established this technique, a full scale structure of five columns and beams was produced. The form of each individual component was the result of an optimisation of the component itself and its placement in the overall system. The structure is an example of a prototypical mass-customised concrete element construction, where mould tectonics played a central part in the final design (figure 14).

ARCHITECTURAL POTENTIALS The architectural potentials of the described casting techniques lie in a simplicity that allows for quick alterations in scale, in concrete element geometry, and in the composition of elements. Factors which potentially allow the techniques to tailor the concrete elements for different architectural applications – at all times keeping the material, technology, and casting technique in mind. As an example, the Fold casting principle is further developed and tweaked into a series of case studies, which are explained in detail in the article ‘Concrete Gridshell’ found elsewhere in this volume.

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GENETICS

AARHUS SCHOOL OF ARCHITECTURE

Genetics Karl Christiansen

My daughter recently got her driver’s license. Riding with someone who is a ’newly-qualified’ driver is a strange experience. Everything is done correctly: disengage, change gear; forward, slightly to the right, forward, engage. Check the rear-view mirror, check the right hand side mirror, check the blind angle over the right shoulder, gear down, check for cyclists over the right shoulder, once again; turn the steering wheel to take the car through a right turn around the corner, straighten out, gear up, and so on – all pedantically correct. Nevertheless there is no real flow, it is all very choppy.

Just a few weeks after, it’s quite a different matter, all manoeuvres overlap, have become intertwined - while we small talk about this and that, the car follows the flow of traffic in the normal way, as if driven by any other experienced driver.

This daughter of mine also plays tennis at elite level. During a game the ball glides forward, over the net, yet close to it, to hit the ground far away in the ’triangle’ presented by one of the opponent’s corners. It then comes back, and is once again returned skilfully over the net, but very close to it, to hit the opponent’s other corner. In this way, the opponent has to go back and forth across the

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court in order to return the ball to my daughter’s court, where she for her part has to move across the court and back and forth in a concentrated rhythm: Forehand, backhand, forehand, and so on and so on. Suddenly, the rhythm is interrupted as the ball hits the ground twice in the same side, but the opponent is immediately punished, and she also has to correct her rhythm. As long as the rhythm remains slavishly predictable, all concentration is on the game, on reading your opponent - when will the exception come? And in what form? But the strokes themselves fall promptly, almost automatically, with great precision.

Suddenly, the opponent is in trouble.

She just manages to return the ball, but without incisiveness, with the result that a high ball is returned at low speed. This gives my daughter time to move forward to the net and focus her concentration on the stroke to come. The situation is advantageous, for now the ’easy’ ball can be returned quickly to a place in the opponent’s court that she cannot reach in time. In my daughter’s mind this shot is already in the bag.

It only remains, with all her attention and with great delight, to strike the ball from

up high, in an obtuse angle, with a powerful quick stroke, sending it to its destination in the opponent’s court, and then….

Well, then the ball goes straight into the net to fall lazily and disappointingly in my daughter’s own court, the ball is lost!

This happens again and again, strangely enough also in top professional tennis matches. It ought to be so easy, but ends so badly! - time after time.

I also fall into this trap. When I am slalom skiing down the red piste in a fixed rhythm, rocking from side to side, I can dream myself away to a beach in Bali – swim fins, bathing trunks, piña colada and everything. While finding my way between trees, markings, humps of snow, fellow skiers, snowboarders and other major obstacles, I zoom down the piste at an incredible speed. This works well, until the moment I direct my thoughts to and begin to plan the next artful turn.

Now don’t forget! Shift some weight to the leg opposite the direction you want to go, bend the knees a bit … and BANG … I fall … to lie buried deep in the snow with skis and sticks pointing in every inappropriate direction conceivable.

I have to start all over.

KARL CHRISTIANSEN

RESEARCH PUBLICATIONS

"Imagine if a musician had to think about every single note, tonation, touch, pause – the result might be sound, but hardly music" Karl Christiansen, Professor, Architect

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GENETICS

AARHUS SCHOOL OF ARCHITECTURE

When I’m unable to fall asleep, really desperately wanting to, never helps. If, on the other hand, I start counting sheep, well, then I fall asleep. By directing attention away from what I seek to achieve, I achieve just that.

Similarly, when strolling through a large city I don’t think: now I need to move my left leg in front of the right leg, and now the right leg forward…etc. And when I have to turn a street corner, to the right, I don’t think: now I have to take longer strides with the left leg than with the right until I have turned the corner and I am, once again, back on course.

Suppose I encounter a curb? Or a staircase? Or I have to step into a bus.

Thinking things through in a concrete manner before acting simply doesn’t work. Instead, we move deftly through the city with its almost infinite number of obstacles; we do so lightly and elegantly, at times even with virtuosity.

Imagine if a musician had to think about every single note, tonation, touch, pause – the result might be sound, but hardly music.

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What is going on here? Well, it would seem that in all these cases the problem is thinking too much about what you are going to do in a forced manner, with the result that it goes wrong. If, instead, you just let things happen automatically things will flow - with ease and elegance.

But can it really be true that if you forget about your actual objective and aim at all that which lies around it, you hit the mark?

There are some indications that this might be true and that, not only will you hit the mark, you will do so with surprising accuracy, in a masterful way. Actually, with a degree of precision which would not have been possible had you taken the immediate and direct approach.

This also applies to architectural form when architecture really is!

Architectural form is so complex in its variety of forms, materials, colours, materialities and meanings, as well as blends of all of these individual elements, that we can hardly embrace and explain it all. Consequently, decisive form has to be generated by other means than by directly dictating and realising it. That's where genetics comes in.

KARL CHRISTIANSEN

RESEARCH PUBLICATIONS

Instead of focusing on geometric form and outlines, attention is directed at the circumstances surrounding the form field - to the facts which will ultimately constitute the specific form. Be they intention, function, choice of materials, manufacturing techniques, static conditions, economic aspects, legislation and other fixed rules, context, local customs and tradition, geographic and climatic conditions, and a wide range of similar surrounding circumstances, which are, in one way or another, at the end of the day, decisive for how your architecture will appear visually. You can see these circumstances as algorithms which are positioned in a mutual relationship to each other and then made to mutate - the form resulting from this mutation will appear in such a dizzying multiplicity that it could not have been achieved in any other way.

Being a good architect consequently means being good at selecting, creating, and joining the right circumstances according to their intrinsic rules. But there is no easy shortcut you can take. Insight and experience have to be

It is in such cases that we talk about architecture being the result rather than the sum of the invested individual parts - that 2 + 2 may equal 5 - of being able to create something which is larger than ourselves.

The audience applauds, the ball is won!

practiced and trained, at times over quite long periods of time, so that skills are built and stored the way you might memorise the verses of a hymn. Ready to strike at the right time and place. ‌ a bit the same way as it is possible for the tennis player, if she has been diligent in her training, to restrain herself, to trust and draw on her technical skills and concentrate patiently on the development of the game – suddenly, the killing stroke will come of its own accord, and now with a power and precision that even she will wonder at.

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AARHUS SCHOOL OF ARCHITECTURE

Tectonics and Topology Optimisation Workshop December 2012 Karl Christiansen and Ruben Borup

The form of the beam should be calculated as optimal in relation to the actions on the beam – seen in the context of static construction.

Students consequently have to choose a design space, supports, and, consequently, the span and load resulting from the beam's dead load as a pointor evenly distributed load.

But the form resulting from computer generation is, if not alien, always surprisingly complex and unpredictable - although invariably correct in respect to the parameters of the starting point.

These parameters can be "adjusted", iteration upon iteration until even the 'architect' is satisfied.

The result, which is unique, is only possible as a generative process.

Further reading on: blurb.com/books/4521150-tektonik-optik

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TECTONICS AND TOPOLOGY OPTIMISATION

KARL CHRISTIANSEN AND RUBEN BORUP

RESEARCH PUBLICATIONS

1. Design space

2. Supports and forces

3. Topology optimisation

A design space is constructed in Rhino. This is the volume defining where topology optimisation takes place. The design must span 120 cm in width and meet individual height criterias.

The model is loaded into SolidThinking Inspire.

Supports, loads, and various optimisation parameters are defined.

Inspire will calculate the forces running through the structure, moving material where it is needed the most. Supports and loads are adjusted until a desired result is reached. By reduce (filtering) the amount of material used, you end up with a structure that clearly shows the flow of forces (compression and tension).

4. Remodeling

5. Slicing and nesting¨

6. Supports

The optimized design is imported into Rhino as an stl-file. The geometry is remodeled using T-splines as Euclidian geometry and traditional NURBS tools are inadequate. The result is a smooth and elegant structure approximating the topology optimised shape.

The model is sliced, numbered and nested on sheets using RhinoNest. This process will point out potential problems in the fabrication process; usually too many parts. The slicing direction has a huge impact on stability, cutting time and assembly.

Using the 1:2 scale model, various designs for the support structures are tested. Supports must be made from sheet material, so folding the material is necessary to make light and strong supports. Obviously, the supports must relate to the support points used in the optimisation process. As an extra design criteria, the optimal support must collapse when the beam is removed.

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TECTONICS AND TOPOLOGY OPTIMISATION

Fabrication 1:1 The final design is sliced and laser cut in 4 mm plywood, then assembled by hand. Some designs consist of more than 800 pieces, so assembly is complicated. Supports are made by hand from 0,5 mm brass sheets. The beam and supports are carefully positioned in the designated domain in the exhibition space.

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AARHUS SCHOOL OF ARCHITECTURE

“… as an institution we, at the Aarhus School of Architecture, continuously look for new approaches in our research and development.

Approaches for finding new architectural forms.

However—the result of our work must find its way to the world around us. Therefore we also continuously appeal to producers and, not least, architectural practices to cooperate with us—so join us—for it is together that we should develop and renew architecture …”

Karl Christiansen, Professor, Architect

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