Formative processes have been discussed earlier, but the procedure of forming is relevant again here since it requires a particular approach in relation to the digital technologies that enable it. Forming is tooling through the generation of components from a mould or form, and is most readily applied for the mass production of consumer products. It has been used to make such architectural elements as façade panels, detail components and other hardware. On site, forming is a long-established process for producing precast structural columns and beams, walls, panels or even whole zones of the building such as circulation cores. Digital fabrication approaches the method in a similar manner, requiring a mould or form which is usually created via CNC milling but occasionally uses rapid-prototyping techniques. The forming process produces positive and negative moulds, also referred to as ‘male’ and ‘female’. Positive moulds are used for thermo- and vacuum moulding, whilst negative moulds may also facilitate casting and injection moulding. Both types afford metal stamping and other comparable methods. Forming is an effective and relatively economical method of making a significant number of components, and as a result it is typical for a great deal of effort, time and cost to be spent in the fabrication of the moulds. The forming process has considerable potential for architectural design, since it may be utilized with a variety of materials and be easily integrated with traditional and digital modes of making. Perhaps to an even greater degree than with folding, the key advantages of this approach relate to full-size fabrication, which makes it an effective bridge between digital design and production.
Forming is a key way of making curvilinear elements. The size and shape of each part is typically constrained by the limits of the mould that may be produced by the CNC machine. This lighting feature by Greg Lynn FORM demonstrates the numerous sections needed for fabrication. Note also the incorporation of a lip around the edge of each part to facilitate connection.
Using CNC routing and milling to create complex formwork for the fabrication of components is a primary method employed by architects, as illustrated by this scale prototype panel for the interior of the CocoonClub designed by 3deluxe.
UNStudio’s design for the Music Theatre in Graz shows the use of forming to provide the fluid geometry of the 3D digital model. The building is structured to combine a unit-based volume – the theatre’s ‘black box’ – and a series of movement-based volumes such as the foyer and public circulation. Because this organizing principle is made constructive, a fluent internal spatial arrangement is achieved. The free-flowing foyer space is made possible by a spiralling constructive element that connects the entrance to the auditorium and to the music rooms above, thus welding together ‘with a twist’ the three levels of this side of the building.
A 3D digital model, illustrating internal fluidity of circulation and foyer spaces.
B The exterior, its translucent façade exposing the internal geometry.
C 3D ‘twist’, made using complex formwork to produce the desired flow of curvilinear concrete.
D The ribbon of ‘flowing’ concrete glides through the triple-height space.
E Additional materials and colour are used selectively to further nuance the sweeping geometry and emphasize its sculptural qualities.
STEP BY STEP FORMING AND CASTING
The integration of digital-fabrication technologies for moulding and casting complex curved forms is a growing area of experimentation. In this example of a scaled bronze version of the Blue Gallery by dECOi/Mark Goulthorpe, the production of the object mirrored the building process.
1 The basic form of the curved surfaces, cut as 2D ply sections, are laminated together and sanded to produce a ‘positive’ form for the sand/resin mould.
2 The moulding process, where a liquid sets in a curvilinear mould, is in fact a scaled-down version of the typical techniques of the composite industry, where resins reinforced by fibre mats are cast in numeric command milled moulds.
3 The casting process in bronze, yielding a sensual and heavily plastic form which was subject to grinding to smooth its edges and then received a blue-grey patina. This process alerted the designers to the potential for non-standard components and spaces to be moulded in this manner, which fed into the casting of components in future projects.
STEP BY STEP FORMING AS EXPLORATIVE PROCESS
This series of models, both digital and physical, was made by Barkow Leibinger to investigate possible iterations of a spaceframe for a building façade. The design development explored different geometric configurations that would provide structural stability.
1 Early digital model of double ‘mesh’ skins.
2 Card model of triangulated modules. Some of the faces are closed whilst others are left open, which, in addition to providing structural rigidity, enables greater variation of lighting effects.
3 A subsequent card model illustrating a more uniform distribution of pattern and structure.
4 This informed a digital model of the spaceframe, which was further nuanced with apertures and rounding between the struts to offer stability.
5 The digital model was then cast as a series of metal modules, using the data to generate formwork for the casting process.
6 These modules were assembled to evaluate their properties in more detail.
7 The resultant module was scaled and returned to the building context using a digital model.
Case study Forming doubly curved panels
Franken Architekten – Bubble, Frankfurt, 1999.
For their design at the BMW Trade Fair, Franken developed the concept of a drop of water to embody clean energy and sustainability. The Bubble was one of the first structures to be completely created with digital means, from design through to construction.
A, B, C AND D Digital simulation software was used to create the shape. In order for the building to appear as a giant water drop, the skin needed to express the balance between internal pressure and surface tension. Using film-animation software, the master geometry of the design was evolved parametrically.
E, F, G AND H The resultant design was then analyzed to explore structural and surface constraints, and areas of significant stress and loading.
I The building’s frame was evolved from the parametric design model, and used to direct the fabrication of the 3,500 individual components that were jet-stream cut from sheet aluminium. These flat, orthogonal sections, when combined, form a three-dimensional double-curved form.
J The cladding elements, which comprised 305 unique acrylic-glass panels, were heat formed onto individually CNC-milled foam blocks.
K Once they had cooled, each panel was trimmed at the edges in preparation for connection to the substructure.
L AND M The Bubble remains a landmark project in the digital generation and manufacturing of buildings, showcasing the first example of a complete workflow of such techniques from start to finish.
Case study Forming components and continuous surfaces
3deluxe – CocoonClub, Frankfurt am Main, 2004; and Leonardo Glass Cube, Bad Driburg, 2007.
3deluxe is an interdisciplinary team from the fields of architecture; art; and interior, graphic, media and product design. From this broad spectrum of specialist knowledge, 3deluxe devises holistic design solutions that range from graphic identities via media installations to architecture – all displaying a coherent aesthetic. A key aspect of this work is the production of organic spaces, as exemplified by the two projects shown here.
The structure of the CocoonClub wall is reminiscent of a semi-permeable cell membrane. The two distinct layers of wall surface mounted in front of each other lends it additional depth. Air conditioning was installed between the layers so that the many ‘pores’ serve as ventilation openings.
A The membrane panels are formed using a casting process, and arrive on site as components.
B These are then stacked and attached to a steel frame, to give the appearance of a continuous semi-permeable skin.
C Detail view looking through the two layers.
The organically shaped, white DJ pulpit hosts all the media technology for the club, and is the central feature of the space. Its sculpted, curvilinear form was fabricated using forming to create sections that were then attached to a steel frame underneath.
D First sections are mounted to the substructure.
E Midway through the installation process.
F The completed form.
The Glass Cube structure comprises two formally contrasting elements: a geometrically stringent, cube-like shell volume and a free-form element positioned centrally in the interior. The undulating, curved white wall encases an introverted exhibition space, and its other side circumscribes the extroverted hallway along the glass façade. Three white sculptural structures – so-called ‘Genetics’ – connect the separate zones. On the glass façade, ‘Genetics’ appear again in a two-dimensional version. The construction of these sculptures necessitated a further, material-specific development. The major challenges were creating a joint-free surface and maintaining the dynamic form based on static principles – much easier to achieve using flexible textiles. The segmented shells of the ‘Genetics’ are compiled from deepdrawn half shells of a mineral material, which can be formed with heat as well as smoothed and ground. For their production, full-size models of the entire sculptures were made.
G The loadbearing structure comprises a steel support surrounded by a wood frame.
H Curved components are heat formed and delivered to site.
I These are connected together to ensure formal integrity prior to installation.
J The formed components are attached to the frame.
K Close-up view, illustrating various components around a ‘Genetic’ node.
L After assembly, the cross-joints were glued together, so that they were no longer visible.
Case study Forming structural elements
Rogers Stirk Harbour + Partners – Berkeley Hotel Entrance Canopy, London, 1998–2005.
A Canopy design.
B Sketches for carbon-fibre beams.
C AND D Digital model for carbon-fibre beams.
E, F AND G Early prototype is assembled as a 1:1 section in the workshop.
This new entrance to an existing building enabled exploration into the use of an innovative building material, carbon fibre. These structural elements were designed and modelled using Rhino, to easily shape the convex and concave surfaces in response to structural performance. The beams are thickest where the greatest torsion is, and more slender at the supports. Carbon fibre is extremely lightweight, strong, fire resistant and can take any shape. The design included forms to accommodate stainless- steel fixings. Using a CNC milling fabrication technique, contractor Bellapart were able to make a positive mould of the main beam. From this, the 16 beams were moulded, the structure tested and made ready for installation.
H CNC-milled mould for forming beams.
I Prototype beams post-fabrication.
J Prototype support section.
K Detail of carbon-fibre beam showing typical surface pattern.
L Strength testing of beam.
