New Approaches To Construction Design Engineering Essay

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Having abandoned the discourse of style, the architecture of modern times is characterized by its capacity to take advantage of the specific achievements of that same modernity: the innovations offered it by present-day science and technology.

The relationship between new technology and new architecture even comprises a fundamental datum of what are referred to as avant-garde architectures, so fundamental as to constitute a dominant albeit diffuse motif in the figuration of new architectures.

Integrating computer-aided design with computer-aided fabrication and construction [...] fundamentally redefines the relationship between designing and producing.

It eliminates many geometric constraints imposed by traditional drawing and production processes making complex curved shapes much easier to handle, for example, and reducing dependence on standard, mass-produced components. [...].

It bridges the gap between designing and producing that opened up when designers began to make drawings.

In architectural curvilinearity Greg Lynn offers examples of new approaches to design that move away from the deconstructivism s logic of conflict and contradiction to develop a more fluid logic of connectivity. This is manifested through folding that departs from Euclidean geometry of discrete volumes, and employs topological, rubber-sheet geometry of continuous curves and surfaces.

In topological space, geometry is represented by parametric functions, which describe a range of possibilities. The continuous, highly curvilinear surfaces are mathematically described as NURBS Non-Uniform Rational B-Splines. What makes NURBS curves and surfaces particularly appealing is the ability to easily control their shape by manipulating the control points, weights, and knots. NURBS make the heterogeneous and coherent forms of the topological space computationally possible.

Blobs or metaballs, or isomorphic surfaces, are amorphous objects constructed as composite assemblages of mutually inflecting parametric objects with internal forces of mass and attraction. They exercise fields or regions of influence, which could be additive or subtractive. The geometry is constructed by computing a surface at which the composite field has the same intensity: isomorphic surfaces.

These open up another formal universe where forms may undergo variations giving rise to new possibilities. Objects interact with each other instead of just occupying space; they become connected through a logic where the whole is always open to variation as new blobs (fields of influence) are added or new relations made, creating new possibilities. The surface boundary of the whole (the isomorphic surface) shifts or moves as fields of influence vary in their location and intensity. In that way, objects begin to operate in a dynamic rather than a static geography.

Animation software is utilized as medium of form-generation. Animate design is defined by the co-presence of motion and force at the moment of formal conception.

Force, as an initial condition, becomes the cause of both motion and particular inflections of a form. While motion implies movement and action, animation implies evolution of a form and its shaping forces.

The repertoire of motion-based modeling techniques are keyframe animation, forward and inverse kinematics, dynamics (force fields) and particle emission.

Kinematics are used in their true mechanical meaning to study the motion of an object or a hierarchical system of objects without consideration given to its mass or the forces acting on it. As motion is applied, transformation are propagated downward the hierarchy in forward kinematics, and upward through hierarchy in inverse kinematics.

Dynamic simulations take into consideration the effects of forces on the motion of an object or a system of objects, especially of forces that do not originate within the system itself. Physical properties of objects, such as mass (density), elasticity, static and kinetic friction (or roughness), are defined. Forces of gravity, wind, or vortex are applied, collision detection and obstacles (deflectors) are specified, and dynamic simulation computed.

Metamorphic generation of form includes several techniques such as keyshape animation, deformations of the modeling space around the model using a bounding box (lattice deformation), a spline curve, or one of the coordinate system axis or planes, and path animation, which deforms an object as it moves along a selected path.

In keyshape animation, changes in the geometry are recorded as keyframes (keyshapes) and the software then computes the in-between states. In deformations of the modeling space, object shapes conform to the changes in geometry of the modeling space.

In parametric design, it is the parameters of a particular design that are declared, not its shape. By assigning different values to the parameters, different objects or configurations can be created. Equations can be used to describe the relationships between objects, thus defining an associative geometry. That way, interdependencies between objects can be established, and objects behavior under transformations defined.

Parametric design often entails a procedural, algorithmic description of geometry. In this algorithmic spectaculars , i.e., algorithmic explorations of tectonic production using mathematica software, architects can construct mathematical models and generative procedures that are constrained by numerous variables initially unrelated to any pragmatic concerns. Each variable or process is a slot into which an external influence can be mapped, either statically or dynamically.

Evolutionary architecture proposes the evolutionary model of nature as the generating process for architectural form.

Architectural concepts are expressed as generative rules so that their evolution and development can be accelerated and tested by the use of computer models. Concepts are described in a genetic language which produces a code script of instructions for form generation.

Computer models are used to simulate the development of prototypical forms which are then evaluated on the basis of their performance in a simulated environment. Very large numbers of evolutionary steps can be generated in a short space of time and the emergent forms are often unexpected.

The key concept behind evolutionary architecture is that of the genetic algorithm. The key characteristic is a a string-like structure equivalent to the chromosomes of nature, to which the rules of reproduction, gene crossover, and mutation is applied. Optimum solutions are obtained by small incremental changes over several generations.

It was only within the last few years that the advances in computer-aided design (CAD) and computer-aided manufacturing (CAM) technologies have started to have an impact on building design and construction practices. They opened up new opportunities by allowing production and construction of very complex forms that were until recently very difficult and expensive to design, produce, and assemble using traditional construction technologies. The consequences will be profound, as the historic relationship between architecture and its means of production is increasingly being challenged by new digitally driven processes of design, fabrication and construction.

Implications of new digital design and fabrication processes enable the use of (vii) Virtual Environments (VE), (viii) rapid prototyping (RP) and computer-aided manufacturing (CAM).

Technologies, which offer the production of small-scale models and full-scale building components directly to and from 3D digital models. Mass-customization is a development of repetitive non-standardized building systems through digitally controlled variation and serial differentiation.

Geometries are precisely described and their construction is perfectly attainable by a computer numerically controlled (CNC) fabrication processes.

CNC (computer numerically controlled) cutting, or 2D fabrication, is the most commonly used fabrication technique. Various cutting technologies, such as plasma-arc, laser-beam, or water-jet, involve two axis motion of the sheet material relative to the cutting head and are implemented as a moving cutting head, a moving bed, or a combination of the two. In plasma-arc cutting an electric arc is passed through a compressed gas jet in the cutting nozzle, heating the gas into plasma with a very high temperature (25,000F), which converts back into gas as it passes the heat to the cutting zone.

In water-jets, as their name suggests, a jet of highly pressurized water is mixed with solid abrasive particles and is forced through a tiny nozzle in a highly focused stream, causing the rapid erosion of the material in its path and producing very clean and accurate cuts.

Laser-cutters use a high intensity focused beam of infrared light in combination with a jet of highly pressurized gas (carbon dioxide) to melt or burn the material that is being cut. There are, however, large differences between these technologies in the kinds of materials or maximum thicknesses that could be cut. Laser-cutters can cut only materials that can absorb light energy; water-jets can cut almost any material. Laser-cutters can cost-effectively cut material up to 5/8 , while water-jets can cut much thicker materials, for example, up to 15 thick titanium. Digital Fabrication: Manufacturing Architecture in the Information Age 3 The production strategies used in 2D fabrication often include contouring, triangulation (or polygonal tessellation), use of ruled, developable surfaces, and unfolding. They all involve extraction of two-dimensional, planar components from geometrically complex surfaces or solids comprising the building s form. Which of these strategies is used depends on what is being defined tectonically: structure, envelope, a combination of the two, etc.

In contouring, a sequence of planar sections, often parallel to each other and placed at regular intervals, are produced automatically by modeling software from a given form and can be used directly to articulate structural components of the building, as was the case in a number of recently completed projects.

Complex, curvilinear surface envelopes are often produced by either triangulation (or some other planar tessellation) or conversion of double-curved into ruled surfaces, generated by linear interpolation between two curves. Triangulated or ruled surfaces are then unfolded into planar strips, which are laid out in some optimal fashion as two-dimensional shapes on a sheet, which is then used to cut the corresponding pieces of the sheet material using one of the CNC cutting technologies. For example, Frank Gehry s office used CATIA software in the Experience Music Project in Seattle to rationalize the double-curved surfaces by converting them into rule-developable surfaces, which were then unfolded and fabricated out of flat sheets of metal.

Subtractive fabrication involves removal of specified volume of material from solids

using multi-axis milling. In CNC milling a dedicated computer system performs the basic controlling functions over the movement of a machine tool using a set of coded instructions static geography.

The CNC milling has recently been applied in new ways in building industry to produce the formwork (molds) for the off-site and on-site casting of concrete elements with double-curved geometry, as in one of the Gehry s office buildings in D sseldorf, and for the production of the laminated glass panels with complex curvilinear surfaces, as in Gehry s Conde Nast Cafeteria project and Bernard Franken s BMW Pavilion.

Additive fabrication involved incremental forming by adding material in a layer-by-layer

fashion, in a process converse of milling. It is often referred to as layered manufacturing,

solid freeform fabrication, rapid prototyping, or desktop manufacturing. All additive

fabrication technologies share the same principle in that the digital (solid) model is sliced

into two-dimensional layers. The information of each layer is then transferred to the

processing head of the manufacturing machine and the physical product is incrementally

generated in a layer-by-layer fashion.

A number of competing technologies now exist on the market, utilizing a variety of materials and a range of curing processes based on light, heat, or chemicals:

Stereo lithography (SLA) is based on liquid polymers which solidify when exposed to laser light. Selective Laser Sintering (SLS) laser beam melts the layer of metal powder to create solid objects.

In 3D Printing (3DP) layers of ceramic powder are glued to form objects.

Sheets of material (paper, plastic), either precut or on a roll, are glued (laminated) together and laser cut in the Laminated Object Manufacture (LOM) process.

In Fused Deposition Modeling (FDM) each cross section is produced by melting a plastic filament that solidifies upon cooling.

Multi-jet manufacture (MJM) uses a modified printing head to deposit melted thermoplastic/wax material in very thin layers, one layer at a time, to create three-dimensional solids.

Sprayed concrete were introduced to manufacture large-scale building components directly from digital data.

In formative fabrication mechanical forces, restricting forms, heat, or steam are applied on a material so as to form it into the desired shape through reshaping or deformation, which can be axially or surface constrained. For example, the reshaped material may be deformed permanently by such processes as stressing metal past the elastic limit, heating metal then bending it while it is in a softened state, steam-bending boards, etc. Double curved,

compound surfaces can be approximated by arrays of height-adjustable, numerically-controlled pins, which could be used for the production of molded glass and plastic sheets and for curved stamped metal. Plane curves can be fabricated by numerically-controlled bending of thin rods, tubes, or strips of elastic material, such as steel or wood, as was done for one of the exhibition pavilions designed by Bernard Franken for BMW.

After the components are digitally fabricated, their assembly on site can be augmented with digital technology. Digital three-dimensional models can be used to determine the location of each component, to move each component to its location, and finally, to fix each component in its proper place.

New digitally-driven technologies, such as electronic surveying and laser positioning, are increasingly being used on construction sites around the world to precisely determine the location of building components. For example, Frank Gehry s Guggenheim Museum in Bilbao was built without any tape measures. During fabrication, each structural component was bar coded and marked with the nodes of intersection with adjacent layers of structure. On site bar codes were swiped to reveal the coordinates of each piece in the CATIA model. Laser surveying equipment linked to CATIA enabled each piece to be precisely placed in its position as defined by the computer model. Similar processes were used on Gehry s project in Seattle. This processes are common practice in the aerospace industry, but relatively new to building.

Computer Numerically Controlled (CNC) fabrication processes are cutting, subtractive, additive, and formative fabrication.

Rapid Prototyping (RP) involves incremental forming by adding material in a layer-by-layer fashion. The digital (solid) model is sliced into two-dimensional layers; the information of each layer is then transferred to the processing head of the manufacturing machine and the physical

product is incrementally generated in a layer-by-layer way.

The ability to mass-produce irregular building components with the same facility as standardized parts introduced the notion of mass-customization into building design and production (it is just as easy and cost-effective for a CNC milling machine to produce 1000 unique objects as to produce 1000 identical ones). Mass-customization, sometimes referred to as systematic customization, can be defined as mass production of individually customized goods and services, thus offering a tremendous increase in variety and customization without a corresponding increase in costs.