Many of the materials used in the production of architecture are processed in or from a sheet format. Whilst they may have radically varying properties – most obviously with respect to colour, texture and thickness – these are essentially planar elements. Contouring changes this physical materiality by using an incremental subtractive technique, not dissimilar to carving, to provide three-dimensional features from what is ostensibly a ‘flat’ sheet material. Carving, of course, is a long-established technique of working with materials in architecture, principally in stone and wood in a period that stretches back to ancient civilizations. The main difference between the two processes lies in the nature of the tooling in each method. Carving is traditionally a manual, crafts-based skill, which has experienced considerable decline in the preceding century of industrial standardization and manufacturing. This situation has altered dramatically through the use of digital fabrication, which offers the possibility of highly articulated and intricately patterned components. Specifically, the implementation of CNC milling and routing enables the designer to systematically remove material through a series of carvings or contours. In contrast to the manual approach, CNC methods are capable of quickly producing a greater number of either non-standard or repetitive elements – and the level of detail in each approach may be comparable. Typical materials used with this process are wood and foams, although metals may also be used.
The tooling opportunities with contouring facilitate a clear dialogue between the digital design information and the making process. However, the subtractive nature of CNC milling and routing renders this technique time-consuming and demanding of considerable amounts of material. This is because the waste material removed to produce the desired contoured surface or component may, firstly, be significant in volumetric terms and, secondly, has been machined with a high level of detail in order to leave the equally sophisticated product behind. It is important to understand the implications of these factors in relation to time and cost in order to ensure that this is the most suitable method of digital fabrication. The process of contouring has enabled architects to achieve highly imaginative effects from traditional materials, by articulating their properties in an effective and transformative manner.
Contouring is readily achieved using CNC routing and milling processes, and may extend surface characteristics by incorporating geometrical variation and complexity into otherwise planar materials. These images show the production of an undulating panel for use in dECOi/Mark Goulthorpe’s design for One Main. To see how this element was incorporated into the final design, refer to pages 136–8.
This project uses the contouring of material blocks to create modular components that are adaptable in use and arrangement. Designed and completed by Faulders Studio for the Berkeley Art Museum and Pacific Film Archive, BAMscape is a shaped assembly of 150 individual curved modules. Each was fabricated using digital methods, which enabled efficient production directly from CAD drawings as well as considerable variation (all the contours are unique).
1 Polystyrene blocks are cut with a hotwire cutter in the first stage of the CNC- cutting process to achieve the individual, contoured geometry.
2 The application of digitally driven manufacturing allows the non-standard elements to be economically viable and easily produced.
3 By cladding in 9mm-thick bendable plywood for the top surfaces and 6mmthick plywood for the sides, the modules are given a protective coating.
4 The use of polystyrene blocks enables channels for cable routes etc. to be readily incorporated on site; here, the modules await delivery.
5 The resulting footprint of the object is 145m2 of undulating curves. Visually bold, structurally innovative, kinesthetically engaging – the design communicates a playful inventiveness, allowing users to engage with the space and reconfiguring modules in relation to programmes and events.
Case study Contouring an object
Gramazio & Kohler – mTable, 2002.
This customizable table series was developed to enable people to design their own table by mobile phone. The mTable is created using contouring processes to sculpt a surface, choosing dimensions, materials and colours. These parameters are directly transmitted to CNC fabrication for the production of each bespoke table.
A AND B In the first stage of the process, the user downloads the mTable application onto a compatible mobile phone.
C The design is then adapted using actions related to pressure, dimension and material before being submitted. The pressure function allows the user to sculpt a smooth landscape for the table surface using one of seven deformers.
D The bespoke design-data order is transmitted directly to the manufacturer, where CNC milling contours the table.
E The contouring process is highly accurate and facilitated by the use of a special bit attached to the machine head, which produces a smooth motion and effect.
F Each unique mTable is shipped, between 8 and 12 weeks later, to the designer/ customer. This results in a wealth of variations within a limited number of parameters.
G, H AND I The mass-customization process afforded by digital design and fabrication techniques is utilized here to offer the role of designer to the customer/end user. For more information on this project see: www.mshape.com
Case study Contouring to fabricate a mould
AL_ A – Spencer Dock Bridge, Dublin, 2006–9.
This 40m-span bridge with its fluid lines and undulating concrete surface takes trams, traffic and pedestrians across the Royal Canal. Its deck edges peel down to reveal a space for pedestrians to pause and take in views of the dock and adjacent Linear Park. The bridge’s underside merges with its piers in a single movement, with joint lines in the concrete designed to accentuate the form’s geometry. The concrete finish provides high visibility against the dark water, and at night the structure is vibrantly lit from below, underlining its fluid form. The bridge’s proportions are unusual, and the design exploits these by treating it as a piece of landscaping. The soft geometry and asymmetry create a piece of infrastructure that resolves tensions between form and function.
A The geometry was remodelled in Solidworks to generate EPS moulds and control assembly tolerance.
B View showing cut-away of EPS block model and dummy rebate network.
C Fabricating directly from the 3D parametric models provided a high degree of control over the geometry. The formwork was manufactured in high-density EPS foam machined on a 5-axis router.
D The foam was milled in increments of greater surface resolution.
E The formed face was sprayed with three coats of polyurea, and sanded. The finished 3m x 1.25m blocks were then shipped to site.
F The blocks were assembled on a ply falsework deck. Position and accuracy were controlled with a network of tongue-and-groove slots that connected to the soffits of the formwork and a digital total station.
G 10mm spacers were left between the formwork blocks to allow for site adjustment and thermal creep. The joints were then sealed, and dummy rebates and reinforcement mat incorporated.
H AND I This innovative use of CNC-cut polystyrene is to date the largest such application of the material. White limestone was used in the concrete mix to increase visibility and reflect changing water patterns. The concrete edges were precast off site, and incorporate recessed lighting and the stainless-steel balustrade.
Case study Contouring to make continuous surfaces
dECOi/Mark Goulthorpe – One Main, Cambridge, Massachusetts, 2008–9.
This office-refurbishment project rigorously deploys CNC machining of sustainable plywood to demonstrate the versatility and efficiency available using CAD/CAM design–build processes. It displaces the combinatorial logic of ready-made components in favour of a seamless, non-standard protocol of customized fabrication. A formal asethetic emerges from such processes, imbuing the design with a curvilinear continuity at spatial and detail levels. Materially, the design assumes an environmental agenda, using a sustainable, carbon-absorbing raw material (forested spruce), translated efficiently into refined and functional elements via dexterous low-energy digital tooling.
A Sketch design, suggesting the plastic potential offered by CNC machining of sustainable timber.
B Developed design, showing local plastic deformation of ceiling and floor for spatial or functional definition.
C Developed ceiling form, with procedural scripting processes for generation of millwork files.
D Scripting logic to nest machining files on plywood sheets for direct milling.
E, F AND G Fabrication of secretarial inflection.
H With the exception of the glass, all design components are fabricated as stacked, sectional elements cut from flat plywood sheets by a single 3-axis CNC milling machine. This unitary fabrication method offers a streamlining of the typical multi-trade assembly techniques, with evident economies of labour, materials and logistics. Therefore, despite the formal complexity that such a process entails significant economy is provided via a single fabricator, with a versatile digital tool, being able to execute the entire project.
I Floor ‘carpets’ prefabricated off site and installed as finished elements.
J Installation of secretarial inflection as a large prefabricated element, minimizing site work.
K, L AND M Milling of mathematical surfaces at end grain of laminated ply.
N Installation of conference table and office desks.
O Finished secretarial desk alloplastically linked to ceiling inflection.
STEP BY STEP CONTOURING MODULAR ELEMENTS
The Landscape Lounge project for the Dutch Embassy in Berlin by ONL uses contouring from high-density foam. These multipurpose objects, designed by an architect and a sculptor, have more than one ‘face’: owing to parametric design and optimal use of the cutting method, five complementary forms in two and even three directions are cut out of one huge block of 1m x 1.2m x 4m material. The lines of the elements, touching each other, result in a set of stackable objects, usable in various ways. Each of the five elements is different in form, typical of ONL’s use of non-standard design to enhance user interaction. Whether used as a high or low table, a seat or a lounge chair, the ‘landscape’ of elements is varied after each use so that a different configuration is left/awaiting each time.
1 3D digital model of molecular element.
2 Parametric iterations of different modules.
3 CAD/CAM interface, showing design data sent to CNC machine to be contoured from a block.
4 Modular element is removed from its original block.
5 Completed component, showing complex geometry.
6 Variations of modular blocks.
7 Stacking potential offers myriad possibilities.
8 Once coated to protect the foam, the elements may be used in a range of different spaces, such as interiors ...
9 ... or positioned, for greater adaption by users, outside.
