The search for optimal structures has been an active question at the practice since its inception, directly inspired by collaborations with architect and engineer Richard Buckminster Fuller, more commonly known as ‘Bucky’: a visionary thinker with whom we shared an optimistic view of technology as a means to create a better society. Bucky showed that technology’s power to achieve ‘more with less’ could create incredible leaps of performance, particularly in our shared areas of interest: shelter, energy and the environment.
Bucky spent much of the 1920s researching advanced methods of construction, and the refinement of lightweight, high-performance structures occupied him throughout his career. One such structure was developed with Norman Foster in the unrealised designs for an innovative office space. The Climatroffice (1971) proposed a mix of buildings – both old and new – brought together in a garden setting and enclosed within a large-scale, materially minimal enclosure. The ovoid form of the space-frame structures was selected for its collective ability to enclose the maximum volume with the minimum surface area. Together with the plant life, this lightweight ‘skin’ would ultimately create a microclimate that was not only energy efficient, but which re-established the rapport between nature and workspace.
For Bucky, the goal of the architect-engineer was to challenge accepted conventions. He was a master of the art of ‘technology transfer’, harnessing new industries to produce pioneering solutions to old problems. Within the current context of computational design, in which computer systems now actively assist in the design process, and digital fabrication, where data drives the manufacturing process, he would likely be inspired by the cutting-edge tools and processes offering new opportunities in architecture and construction. Today, through digital analysis, individual components can be tailored to achieve the maximum strength while using the minimum material – to do ‘more with less’ – subsequently reducing the material waste and embodied energy of buildings. At the same time, the ability to directly fabricate parts from digital designs enables greater complexity of structure, customisation of parts and rapid manufacture.
These developments and technological opportunities are driving our research into material and structural optimisation and advanced construction methods. The Specialist Modelling Group (SMG) – a multidisciplinary team of designers at the intersection of computational design, building physics and research at Foster + Partners – has been leading the inquiry into efficient shapes and materials and their application at various levels of design, from modelling all the way to construction.
An important moment in the search for optimal structures was the practice’s investment in 3D printers and rapid prototyping facilities in 2003. These instruments offered accelerated means of fabricating seemingly endless prototypes, a process that was further assisted by computational design tools that could formulate almost infinite variations in shape and form. The geometric freedom afforded by computational design and the ability to produce physical representations of these designs with 3D printers permitted a deeper investigation into the strongest, most efficient and most flexible shapes that might be effectively used in construction. Generating, testing and synthesising solutions – previously achieved partly through the labour-intensive task of hand-making hundreds of physical and digital models – could now be done incredibly quickly and flexibly.
One of the first projects that took advantage of these technologies was the Yacht Plus boat (2005). It became apparent that the complex geometry of the hull and superstructure would take too long to model and would lack the necessary accuracy if traditional hand techniques were used. Three-dimensional printing proved to be a rewarding process – different individual models could be produced from one digital file, and the design team and client were able to see an exact model of the yacht for the first time, enabling quick and accurate reworking. The benefits for the wider office were immediately apparent – the 3D process was fast enough for the architectural design cycle, and could better handle the increasing number of complex, computer-assisted projects.
Further to its accurate and rapid representation of complex geometric structures, 3D printing also assisted analysis of designs on an operational level. Colour printing capabilities allowed for the visual representation of environmental data, such as solar exposure and airflow, directly onto the model. Architects and engineers could then more easily assess environmental and community impact, and tailor their designs accordingly. This method of analysis was deployed in designs for the Duisburg Harbour Masterplan in Germany (2007), which saw the successful urban renewal of a former industrial harbour into a well-connected, mixed-use quarter. The masterplan for this area had a strong ecological agenda, one which prioritised alternative methods of energy generation and which set the tone for later infrastructure projects. The in-depth analysis of sunlight paths on structures within the plan allowed for the optimum design and placement of solar panels across buildings, and thus the effective harnessing of available energy.
These digital advances had immediate benefits at the level of design and modelling but, naturally, the ease and efficiency of rapid prototyping rose the question of how this technology might be used at the level of construction. To extend such potential from models to buildings in the real world, a change in scale was needed, as well as the application of more conventional construction materials beyond the sintered powder used for modelling purposes. The desire to investigate at this level led to affiliations with research partners that were already developing these new technologies themselves.
The SMG’s work with a consortium of partners from across academia and industry from 2006 onwards marked a major advancement in printed construction, with the development of a process of 3D concrete printing. We spent time with the consortium at Loughborough University, gaining first-hand experience of the concrete printing process and exploring the different building elements that might be produced in this way. We helped with mixing and fine-tuning a concrete recipe, noting how the material behaved – how it flowed and cured and how long it would take to do so. Concurrently, the fabrication tools were adjusted and adapted to best handle the material – both in terms of the actual extrusion of the material, and the manipulation of the machine’s movements.
We then designed, simulated, fabricated and physically tested a range of prints for different construction applications. These included a curving wall made from experimental bricks that were designed for optimal thermal, acoustic and structural performance. Through such tests, we discovered that taking advantage of the characteristics of the fabrication method, such as the behaviour of the material and the printer’s movements, could lead to unique, customised building elements. Mastering materials, tool design and robotic control were all key to being able to fabricate the complex structures being generated digitally.
Another experiment undertaken with the consortium at Loughborough University directly demonstrated the real-world potential of rapid prototyping technologies. As part of Save the Children’s ‘Festival of Trees’ charity event, we helped produced a two-metre-high nylon tree. It comprised two main elements – a silver-plated cone containing an LED light within and an outer layer of ‘foliage’. Due to its size and complex geometry (the design of the leaves was generated by a customised computer programme), it was necessary to manufacture the structure in components. At this point, construction and fabrication parameters were still relatively strict – it was crucial that all components could be efficiently nested within the rapid prototyping machine’s build chamber. Nevertheless, the project offered a first taste of what it could be like to design, print and manufacture a large-scale final product.
Alongside experiments with concrete and other construction materials, we were looking into the possibilities of 3D printing on an extra-terrestrial level. As part of a consortium set up by the European Space Agency in 2011, the SMG explored the possibilities of printing with regolith (the dust, soil and rock that covers the surface of a planet) to construct a habitat on the Moon. To minimise the environmental and financial costs and the risks of transporting materials and humans to the Moon, the development of autonomous manufacturing processes (robots with 3D printing capabilities) made it feasible to use found regolith on the Moon’s surface, meaning only binding material need be transported from Earth. So the primary challenge ultimately became the design of a structure that used as little binding material as possible yet achieved the structural requirements of the habitat.
We designed a structure inspired by the lightweight internal structure of bird bones. Following the principles of optimisation in nature, the structure worked on the premise that material is expensive but shape is cheap – it costs very little to devise a complex shape in nature, it’s data driven, but material takes energy to produce and mould. The efficient internal structure ensured the minimal use of regolith binder whilst maximising the structure’s strength – an important factor when considering the Moon’s volatile surface environment.
A full-scale prototype printed using a material approximating lunar regolith demonstrated the feasibility – in both production and structural terms – of the design, which has since been used to inform subsequent iterations of the lunar habitat. Not only has this research contributed to a coherent vision of permanent habitation on the Moon, and potential developments on Mars, but it has similarly contributed to the discovery and advancing of optimal structures that can be used here on Earth.
Looking to nature when seeking optimal forms in design and construction is an age-old practice. As Martin Kemp said in a talk discussing the legacy of Buckminster Fuller: ‘Intuition of the resonances between natural and human structures is as old as the oldest surviving writings on architecture – even older if we take into account Aristotle’s fascination with nature’s ‘constructivists’, such as the cell-building bee and geometrically accomplished spider.’
Bones are the ultimate in optimised, efficient structures. Having evolved over millions of years, they can self-heal when damaged, have an adaptive internal structure that responds to external pressures and thus loses or gains density as required, all whilst being incredibly strong and lightweight while using minimal material. In partnership with a PhD candidate at the Royal Veterinary College in London, the SMG studied the development of structures and bone growth and the potential application within architectural design.
In this case, the research was geared towards developing a computational design tool that could drive the distribution and alignment of materials within a building part according to the stresses inside the required shape. The open-cell micro-structure of bones varies in density and alignment in response to stresses, so that regions of high stress in your bones are nearly solid and vice versa. We eventually developed this research into a software tool that facilitates the design of 3D-printed, structurally efficient building blocks of a non-standardised, customisable shape. And critically, at speed – the generation of multiple designs and subsequent tests undertaken to determine the highest-performing, most materially efficient structure for a design were no longer necessary. The best structure for a component could be determined at the click of a button.
Designing an optimised form in isolation is one thing; designing an optimised form against design, structural and manufacturing constraints – alongside aesthetic drivers – is new territory. Nevertheless, recent projects at Foster + Partners have demonstrated how this is indeed possible and have provided inspiration for future design possibilities.
At the Maggie’s Centre in Manchester (2016), the entire structure is comprised of timber beams developed with optimal structural and material efficiency in mind. The beams that make up the building frame were designed as trusses that reflect the magnitude and orientation of the loads acting on them – any portion that is superfluous to the structural support has been removed. Computer-aided analysis of the stresses within the beams indicated where material could be optimised, resulting in a materially efficient and aesthetically unique lattice truss beam. These were milled using a CNC (computer numerical control) machine, the geometry for which was taken directly from a 3D model generated in Rhino (computer-aided design software) during the design process.
With Maggie’s, the goal was for a cantilevering glulam beam that could be optimised to minimise weight, maximise strength, and demonstrate a unique design aesthetic. The practice’s research into optimised structures, efficient materials and the development of software that could best distribute this material according to specific structural requirements made this project possible. And interestingly, it revealed the aesthetic, as well as sustainable, potential behind structural optimisation.
The Maggie’s beam is a promising candidate for rapid manufacturing, although the graduation from rapid prototyping has yet to occur at the level of architecture. Yet advances in other industries are encouraging – many Formula 1 teams already take advantage of rapid manufacturing. Renault F1 cars use a cooling duct manufactured using 3D printing. Its complex geometry meant that it couldn’t be manufactured using traditional methods. Significantly, the duct has gone through several iterations as the car has changed and evolved, and the speed of the manufacturing process means it is able to keep up.
To be able to 3D print large structures like the beam at Maggie’s for use in buildings, the technology must be able to manipulate conventional construction materials such as timber or steel. In 2016, in partnership with Cranfield University, Autodesk, BAE Systems, Vestas and others, the practice was awarded an EU grant to develop, build, and test a large-scale 3D metal printer.
Our role in the consortium was to develop a new design approach incorporating all the manufacturing constraints – such as the resolution of the metal deposition, the reach of the robots, or the radii of machining tools – and produce a demonstrator part to show its potential application in the construction sector. Taking inspiration from Maggie’s, we sought to create a structurally and materially optimised steel cantilever beam.
Over three years, we helped developed the tools and associated software that would make the printing of metal building elements possible. Incorporating both additive (3D printing) and subtractive (milling – a standard manufacturing process) properties, the robot combines new and existing technologies to produce a method of fabrication that can not only produce customised, optimised pieces, but also do so at speed.
This is a truly advanced method of construction, and one that offers a flexibility and sustainability so far unseen in the construction industry. At this early stage, 3D printing remains relatively costly as a method of production compared to conventional techniques, but the experimental designs developed during this project helped us understand where value can be added. That is, for optimised bespoke parts with complex geometries.
Should Bucky have been alive today, he would surely be delighted and inspired by current technological developments and their potential for application in the design and construction industries. Just like that of the theoretical Climatroffice, the design for Maggie’s Manchester comprises a lightweight, high-performance structure that is not only energy efficient, but which reinstates the rapport between humans and nature. Crucially, the dream of Maggie’s has become a reality. A reality made possible by the embrace and harnessing of new, cross-industry technologies and digital advances. The various research projects undertaken by the SMG have not only advanced the design of optimised structures, but also their rapid production and construction. Further development of computation and fabrication is already permitting the interface of design and digital manufacturing, allowing for production to be coordinated from file to factory to site. This will only extend our geometric freedom in design, and further streamline the architecture and construction process.
27 April 2020
Sam Wilkinson, Josh Mason
Sam Wilkinson (Environmental Design Analyst) and Josh Mason (Design Systems Analyst) are members of The Specialist Modelling Group at Foster + Partners, a team of multidisciplinary designers at the intersection of computational design, building physics and research.