By contrast with the processes described above, three-dimensional (3D) scanning inverts the relationship between digital information and physical object. This technology reads information from existing physical sources, such as a model or building, and translates this into the computer as data, forming a digital version that may be furthered manipulated using appropriate software. In relation to the digital fabrication techniques discussed thus far this might seem counter-intuitive, but there may be significant advantages in this method. 3D scanning provides a ‘bridge’, across which design ideas may flow in an dialogue between physical modes of representation and digital design tools. A number of architectural designers retain a preference for physical models, and their designs may involve highly complex geometry and spatial arrangements. The importance of physical modelmaking cannot be overstated for architectural education and practice, and it has witnessed something of a renaissance in the last decade or so – frequently aided by digital fabrication techniques. Indeed, the tangible nature of physical models makes them highly versatile design tools, as they may be quickly produced and manipulated and allow a direct engagement with spatial features that are not always as easy to produce on a screen. In these situations, 3D scanners afford a translation of this design information rather than generation of it. Through the conversion of physical characteristics into digital data, this may be implemented in digital fabrication processes to make further models, prototypes and building components with a high degree of accuracy and formal integrity. This may seem an absorptive activity if we already have a physical object, but the important aspect here is the capacity of the computer to handle and refine digital geometry in a manner that would be extremely difficult to accomplish with the original artefact. By importing this information into the computer, a variety of software may be used to evaluate and optimize the design’s properties in relation to, for example, material, structural, thermal and acoustic performance.
The use of a digitizer or digital arm may provide a key element of the design process, offering fluidity between different modes of inquiry and production. The physical model is first scanned by tracing the digital pen over its surface, so that the information of its physical features and geometry may be converted into digital data. Once this data is in the computer, software may be used to further transform it and manipulate the design in a manner that would be difficult to achieve using physical modelmaking techniques alone.
3D laser scanning is transforming the way architects and the construction industry obtain site and contextual data. The accuracy of laser scanners to ‘read’ their environment and then, through conversion software, to make this data available for use in CAD programs allows designers to work with very precise information. It also enables speculative ideas to be tested three-dimensionally prior to implementation. This latter aspect has been particularly valuable in collision analyses, whereby engineers are able to check pipe routes, etc. in spaces that would traditionally be difficult to survey.
For their design of the East Pavilion at the Groninger Museum, Netherlands, Coop Himmelb(lau overlayed three-dimensional volumetric sketches which developed into a sketch model providing a first ‘emotional imprint’ of the concept. A digitizer was then used, enabling the designers to maintain the original gesture of the sketch model and fix it precisely within a three-dimensional grid. This process sought to capture the liveliness of the sketch and translate its sculptural details to the actual building. The digital model was subsequently enlarged stepby-step in order to consider structural and spatial details, and ultimately was used directly in the production of the pavilion parts.
The technology of 3D scanners typically uses a laser to scan or ‘read’ the physical features of the object being translated. Depending on the type of object being scanned, the laser may be housed in a digitizer (sometimes referred to as a digitizing arm) or a tripodmounted box similar to a camera. A digitizer enables the designer to guide the laser over the surface and spaces of small physical objects to gather data. In the case of less manually operated equipment, the scanner and tripod are set up and programmed to scan the required area, for example a building’s façade, and do this in an autonomous fashion. Both these scanning approaches are known as ‘reverse engineering’. The data from the physical artefact is assembled in the computer as a pattern of coordinates called a ‘point cloud’. This arrangement of information is then translated using specialist software to provide a precise digital model of the original object. The digital model may then be exported to other CAD programs for further development or to integrate with other data as necessary.
Case study Digitizing architectural design
3XN – Louisiana Pavilion, 2009.
The Louisiana Pavilion was a collaborative project to build with biodegradable and energy-generating materials, creating an energy-self-sufficient architecture that also can be part of, and decompose within, the biological cycle after use. For the outer shell of the sculpture, glass-fibre composites were replaced with a bio composite from flax fibres cast in biological resin, whilst cork sheets replaced polystyrene foam for the inner core.
On top of the pavilion are placed 1mm-thick flexible solar cells cast in thin film, making them applicable to double-curved surfaces. Piezoelectric materials, which generate electric current from the weight of visitors, are laid in the floor. Combined, this gives the sculpture enough energy to power the integrated LED lights. The pavilion has a coating of hydrophilic nanoparticles that makes its surfaces self-cleaning: rainwater is dispersed beneath the dirt on the surface, leaving it cleaner.
A Design development through physical modelmaking, exploring curved forms and loops.
B Further development of the geometry, with loops becoming narrower in width.
C Digitizing the model to translate physical information into digital design data.
D Fabrication process: casting elements with 80mm cork core.
E Adapting the elements once removed from their moulds, including sanding and filling as necessary.
F First priming of a component.
G Pavilion form begins to emerge through text-assembly process.
H First layer of paint is applied prior to self-cleaning layer.
I The pavilion retains heat by using phase-changing materials. The material retains the sun’s energy, releasing it when the temperature drops. When the temperature rises, the material absorbs energy and is liquefied at exactly 23 degrees Celsius. When temperature drops, it solidifies and releases energy. It is estimated that phase-changing materials can cut costs by 10–15 per cent on heating and cooling of buildings. Adapting new sustainable materials to digital modes of production was a huge challenge in itself. The learning process of substituting synthetic materials for biological counterparts spanned the entire project, revealing many obstacles and producing innovations on the way.
