BACKGROUND/INTRO:

Parametric can be defined as a tool that provides for

a powerful conception of architectural form . By using parametric, one can

create an infinite number of similar objects, geometric

Manifestations of a previously articulated form (

forms of variable dimensional, relational or operational dependencies) When we

assign specific values to those variables, and if values change accordingly,

potentially infinite range of possibilities are created. So, in a parametric

design, it is the parameter s of particular design that are declared and not

its shape. By assigning different values to the parameters, different

object/configurations are created.

Parametric design often involves a procedural,

algorithmic description of a geometry. Parametric

are particularly useful for modelling the geometry of complex building forms.

Their successful application requires careful articulation of clear strategy of

tectonic resolution, such that a clear description of interdependencies can be

achieved. Parametric approach to design, if consistently

applied from its conceptual stage to materialization, profoundly the entire

nature and hierarchies of the building industry, as well as the role of the

architect in the processes of a building. 21ST century Architects

started to design the structures not the specific shape but the set of principles

encoded as parametric equations. Parametric design calls for the rejection of

fixed solutions and for an exploration of infinitely variable potentialities.

Recently, the use of the term “parametric design” has

been widely expanded in the architectural work, mainly associated to the use of

advanced digital technologies in complex projects (Meredith el al.) However,

this concept and its applications in architecture have not been properly

clarified. The documents and programs devoted to parametric systems scarcely

indicate definitions, basic characteristics and/or general uses in building

design. They usually mention specific geometrical operations and/or constructive

developments, this article reviews the meanings of the term and its use in

documents referring to architectural design, as well as early works applying

parametric techniques in the generation of the building form; looking for the

identification of its conditions and its participation in the design. T The first

building brought to life in which the use of parametric systems is said to have

been used are the Philips Pavilion designed by Le Corbusier in 1958 (though without computational

methods).parametric techniques have been detected, tri-dimensional digital

modeling was used. The explicit use of variable curves for the constructive

solution and cultural expression of buildings that suggest specific properties

of

Parametric design in architecture

OBJECTIVES

Scope of parametric design in

contemporary architecture i.e structure,forms,materials etc

Analogue parametric design

One of the earliest examples of parametric design was the upside down

model of churches by Antonio Gaudi. In his design for

the Church of Colònia Güell he created a model of strings

weighted down with birdshot to create complex vaulted ceilings and arches. By

adjusting the position of the weights or the length of the strings he could

alter the shape of each arch and also see how this change influenced the arches

connected to it. He placed a mirror on the bottom of the model to see how it

should look upside-down.

Gaudi’s analogue method includes the main features of a computational of a

parametric model (input parameters, equation, output):

·

The

string length, birdshot weight and anchor point location all form independent

input parameters

·

The

vertex locations of the points on the strings being the outcomes of the model

·

The

outcomes are derived by explicit functions, in this case gravity or Newtons law

of motion.

By

modifying individual parameters of these models Gaudi could generate different

versions of his model while being certain the resulting structure would stand

in pure compression. Instead of having to manually calculate the results of

parametric equations he could automatically derive the shape of the catenary

curves through the force of gravity acting on the strings.

Sketchpad

:

Where

Gaudi used physical laws to speed up his calculation of parametric

equations, Ivan Sutherland looked to the

processing power of digital computers.

Sutherland

created an interactive computer-aided design program called Sketchpad. Using a light pen, users could draw lines and arcs that could

be related to each other using constraints. These constraints contained all the

essential properties of parametric equations. Users could experiment and

explore different designs by altering the parameters of an entity and let

Sketchpad do the calculations and redraw the geometry according to the

constraints imposed upon it.

METHODOLOGY:

CASE STUDIES

the waterloo

international station, London, 1993

Waterloo Station,

located in the heart of London, is a major international

train terminal, moving more than 15

million passengers a year in 60,000m2. In 1993 it had to be extended to become

the main terminal for the Eurostar train which enabled a fast connection with

Paris and Brussels. The extension and complete renewal of the terminal was led

by of Nichols Grimshaw´s architectural office and several engineering teams.

The purpose of the project was to complete the station incorporating an

expression of smooth flow, to evoke the industrial era, but also the new way of

transportation (Grimshaw, 2010; McGuckin et al, 1994). The area available for

the extension had the necessary width to accommodate only five additional

railways, limited by the electrical network on one side and the roads on the

other, in a winding area and that narrowed toward the interior. The extension

had to be added to the existing station. In doing so, it provided uniqueness by

showing new traveling possibilities, especially though its 400 m-long roof. The

cover was a particular technical challenge

due to its asymmetric shape in the acute

profile of the area and due to the fact that it had to rise up progressively to

fit the height of the trains. The eastern side is clad entirely in glass.

Towards the entrance it offers and impressive view of the River Thames and

Westminster and on the other side, it becomes a panoramic showcase for the long

Eurostar trains. Structurally the roof structure consists of pairs of

three-pinned bow strings arches; the central point displaced towards one of the

sides enables the bow shape in the higher area from West to East. This complex

structure covers an area that goes from 50 m wide in the entrance to 35 m

towards the end of the platform. The roof is flexible, with a limited range of

glass tiles of different sizes overlapped that can shrink and expand according

to the different spins of the roof. The structure is formed by two dissimilar

curved trusses, a larger one stretched in the inner side and a smaller one and

curved, stretched in the top end. Also, the beams make up 35 modules that vary

in dimensions.

The design was modeled by Lars

Hesselgren in the software I_EMS, and afterwards it was re-modeled by Robert

Aish with Microstation Generative Components. The trusses were defined by a

program that modifies the inner measurements of each module according to the

proportional scale factor to the length by means of Pythagorean relation

keeping the centres. for the radial layout of the smaller pieces. By propagation

of the formula, changing the wide of the structure (the chords of curves) and

maintaining the central axis like a curved profile. Such produces a continuos

surface with a variable section, with proportional heights of the beams

according the lights of support. The mathematical description enabled the

generation of each design by means of altering the numerical parameters

(Szalapaj,2001).

The covering is the main architectural

challenge of the Terminal and its magnitude provides the perception that almost

the whole building is enclosed. Shifting the attention from the vault work

composing the old terminal (refurbished as warehouses and food courts) to a new

fluid space that covers a parking lot next to the underground and two levels of

viaducts above which stand two floors for passengers (arrivals and departures).

The design shows the variation of structure that resembles mobility and

technology of new transportation media.

The fish, barcelona,

1992

The group of buildings executed by Frank

Gehry in the city of Barcelona from 1989 to 1992, were part of the plan elaborated

for the Olympic Games, with the purpose of recovering the coast line (Dal Co et

al,) It was an industrial area,

segregated of the city by the railroad lines that had turned the nearby beaches

into waste deposits. Therefore, it was considered to integrate the urban layout

to the coastline through a system of public spaces and equipment. Including the

Hotel Arts and adjacent commercial areas designed by Frank Gehry and associates.

The project considered a surface of 14,000 m2 organized around a central patio

between the hotel and the beach, forming multiple routes with restaurants and

bars.

The roofing of the patio considered a 49

m long and 30,5 m tall metallic structure that acts as a protection from the

sun. Two basic parts are noticed: a supporting white steel reticular structure and

a metal cover that evokes a fish surface.

In Frank Gehry´s work, the fish is a

recurrent figure since its beginnings, used in the form of lamps for the

unbuilt project of Smith House and the Collaboration Exposition in 1981. He

worked with a model and scales that revealed him the symbolic potential of this

figure (Gehry, 1988). Also that year, the project for the reinsertion of houses

in Michigan included a fish-shaped hotel. However, he was only able to realize

it in light sources for the Venice restaurant and in other lamp proposals for

the Formica´s in 1982. Two years after he exhibited in Nueva York the design fish-shaped

cells. Also, in the proposal for the Fish Dance Restaurant in Kobe, Japan in

1986, he incorporated it as sculptures in the facade of the

building. For the design of this roof in

Barcelona, the first fish-shaped set up that he uses at architectural scale,

Gehry´s study used the software Catia, by Dassault Systemes, previously applied

to the design of cars and aircrafts. This computer program enabled to work on a

digital model in three dimensions and to be connected with the production or

the digitalization of material models. It is worth mentioning that the

physical models occupy an important place

in Gehry´s design process to encourage designers to experiment and get away

from the outlines of the orthogonal geometry. Therefore, computer programs

combine in a coherent digital representation the demands of the constructive

system and the experimentation with non-conventional shapes. Gehry states that

the relationship between the design solution and the cost that its elaboration demands

constitutes one of the most important variables in the decisions of the shape.

Maintaining the equilibrium between the architectonic characteristics of

volume, plastic expression, constructive system and materiality, is a task

conditioned by the budget. James Glymph, responsible for the digital design,

first made contact witJ. Mitchell, professor in Harvard who, together with the

student Evan Smythe, developed the basic design model in the software Alias

(Shelden, 2002). However, when using it,

it represented a curve-shape. materials and textures, but in smaller elements,

by using the set up of small intertwined pieces forming the support and cover

at the same time. In this case he used flexible strips fitted in the pipe ribs

of the structure, and he required adjust these two arrangements by the digital

model in CATIA. He understood then that he had to separate the supporting structure

from the representative surface, as it has happened often in the history of

architecture, for example, with the renaissance domes and more recently in the

Sydney Opera House; laying out a support inferior scheme and a sustained

variable cover. But this strategy requires a precise trace Of different curves

to combine them with regular distances of the support and accurate fabrication

of pieces. This geometric interrelation between the structure’s modulation and

the complex curvature surface led to the challenge of using digital parametric geometries

that generated a new step in the professional work, allowing construction of

curved profiles for symbolic potential of buildings.

RESULTS AND DISCUSSIONS:

The

Current Situation – Conventional Design.

The

current market economy requires project teams to design quickly, efficiently and

cheaply; however, research shows that successful design is largely a function

of clear definition of end-user requirements (Rolland, 2005) and the generation

and multidisciplinary analyses of a large quantity of options (Kelley,

2006).There is always a continuous tension in every project between design

exploration and process efficiency. The design phase is virtually endless. The

designer can stop designing when he feels that the time invested in the process

is not equal to the value added to the artifact. In the meantime, with tight

working schedules and tense project delivery dates, not all designs are

thoroughly studied, assessed and evaluated, and thus better performing designs

are likely left undiscovered. A recently conducted study by Gene & Haymaker

(2008), made a benchmarking survey of existing conceptual high-rise design

practice to determine the performance of leading design teams. It was found

that a multidisciplinary team averaging 12 people can normally produce only 3

design options during a design process that lasts 5 weeks. It was also found

that most of this time is spent by architects on generating and presenting a

small number of design options. Little time is dedicated to establishing and

understanding project goals and running multidisciplinary analysis. These

analyses are inconsistent and primarily governed by architectural rather than

multidisciplinary criteria. From the previous discussion, we can point out a

real need for an approach to design that can explore the undiscovered

solutions. In order to understand the potential change in the organization and

composition of the design process, we need to develop an in-depth understanding

of the meaning of parametric design, parametric thinking and the terms

associated with their use in contemporary architecture.

Parametric

Design – Basic understanding

Parametric

can provide for a powerful conception of architectural form by describing a

range of possibilities, replacing in the process stable with variable,

singularity with multiplicity. Using parametric, designers could create an

infinite number of similar objects, geometric manifestations of a previously

articulated schema of variable dimensional, relational or operative

dependencies. When those variables are assigned specific values, particular

instances are created from a potentially infinite range of possibilities. Parametric

design can be defined as a series of questions to establish the variables of

design and a computational definition that can be utilized to facilitate a

variety of solutions (Karle & Kelly, 2011). Instead of modeling an external

form, designers articulate an internal generative logic, which then produces,

in an automatic fashion, a range of possibilities from which the designer could

choose an appropriate formal proposition for further development (Kolarevic,

2003).Parametric thinking is a way of relating tangible and intangible systems

into a design proposal removed from digital tool specificity and establishes

relationships between properties within a system (Karle & Kelly, 2011) From

the previous, we can point out the core idea of parametric design in which

variation and flexibility and information control are the main aspects of this

design approach. It is important to understand that, in parametric design, it

is usually difficult to categorize the implications clearly between the

process, the designer and the tools. It is difficult to imagine parametric

design process without a tool that aids the algorithmic sequencing of design.

In light of these understandings, the next section of the paper discusses the

implications of parametric approach on design thinking.

From

Conventional to Parametric Thinking

In a deep

sense, parametric modeling is not new: building components have been adapted to

context for centuries. Conventional CAD systems focus design attention on the

representation of the artifact being designed. Currently, industry attention is

on systems in which a designed artifact is represented parametrically, that is,

the representation admits rapid change of design dimensions and structure

(Aisha & Woodbury, 2007). Parametric thinking pushes back on the

conventional architectural design process and negotiates multiple variables

that define a series of rule-sets. It asks architects to operate quicker and

smarter, juggling multiple systems with speed and efficiency. Published

theory concerned with architectural parametric design tasks typically focuses

on conceptual design phase. Significant research by Michela Turin et al. (2011)

was conducted in this area, in which parametric design as well as genetic

algorithms were used to explore performance driven geometries and structures in

the conceptual phase. In the meantime, observations from research and applied

practice show that parametric tools are typically being applied to design

development problems rather than the early conceptual formulation of the design

(Hudson, 2008). In either cases, there is no doubt that some profound effects

on the design process can be observed. We can also find some important

analogies between conventional and parametric design as would be elaborated in

the next section.

The

Commons of Conventional and Parametric

At one

level, parametric thinking is analogous to conventional design processes

(Figure 1) in that a set of conditions – or parameters – are identified

and analyzed, then preliminarily synthesized, tested and reiterated, and

ultimately implemented. In any design process, if the set of conditions

are misdiagnosed or misunderstood, the resulting design solution has limited

potential to flourish and design integrity suffers (Sanguinetti & Kraus,

2011). It is also worth noting that parametric problem does not need to be

thoroughly well-defined, actually the incomplete description of the problem is

possible in a parametric setting. This can be described as acquiring knowledge

through tinkering or exploration as described by Hudson (2008).

Figure1:

Negotiation

between problem and solution through three activities of design process.The

starting point in parametric problems will also be influenced by knowledge. The

starting state is defined either by choice of an existing solution or similar

solution from a similar problem, or by specifying an initial set of parameters

(Hudson, 2008). The designers tend tolerate and draw analogies between current

problems and previous solutions in the designers memory which is often called

“case based, case retrieval or recall”. The notion of recall has-been

related to problem analysis and selection of initial “prototype”

(analytical descriptions of a problem) based on knowledge of a library of

previous prototypes. This prototype is then adapted to suit the new problem

based on knowledge of the new condition. The prototype includes descriptions of

relational, qualitative, computational knowledge and context knowledge.

Once a

design has been evaluated it may or may not satisfy constraints and

requirements. Through knowledge of the task the designer must either select to

try and improve the designer reformulate the problem. If the design is to be

improved, a method or operator (Mottaand Zdrahal, 1996 in Hudson 2008) must be

selected and applied in order to fix a design so that it satisfies some

constraints. Choice of method or operator is determined by knowledge of the

behavior of the problem. If reformulation is selected (this is common for

architectural problems) the analytical stage of the design must be revisited

and parameters and constraints adjusted

CONCLUSIONS:

Parametric design has been spread out in

architecture without complete clarification of its particular features. This text

at the beginning reviews the connotations of the term, disclosing its mathematical

and social meaning; as well as the first documents that mention this technique

in computer graphic and architectural design, observing a geometric and

constructive sense. Then three works are described, in which initially these

techniques were applied, manually in the Philips Pavilion by Le Corbusier and

Xenakis in 1958, and with incipient

computer systems in the Fish of the Olympic Village of Barcelona, by Frank Gehry

in 1992 and the extension of the Waterloo Station in London by Nicholas

Grimshaw

These projects show a detailed handling

of curve-shape forms in significant elements for construction, using relatively

complex geometrically procedures, in the last cases digitally, which stand out

because the profile in an irregular manner, in the encircling walls of the

Pavilion and the covering of the Fish and the Waterloo Terminal. This variable profile

is the essential property of the parametric equation curves, which suggests a

formal definition of the parametric design; distant from external references,

restrictions or regular alterations, which are the general interpretations of

the concept parameter gathered from documents connected to constructive

modelling. In this sense, a strict parametric design condition is observed in

these architectural works, associated to variable curve-shapes. Using different

procedures and tools, but all related to trace irregular bend shapes, composed by

diverse profiles and modular surfaces related. In order build a coherent three-dimensional

geometry of complex volumes.

parametric techniques that provide the

geometric control of these irregular figures participate in specific actions,

which generate overall attributes of the shape; its constructive resolution and

its symbolic projection within a comprehensive architectural control. In this sense,

the parametric technique plays an instrumental role, but also provides with an

expressive potential. the parametric design capabilities open possibilities to

the architectural work in a formal, as well as in the constructive and cultural

sense.

Discussions about how parametric

thinking ought to change the design process is far from conclusive. However,

new programming paradigms, new ways of structuring code, new code libraries,

new environments for generating code and new ways of managing code development

are main stream of Computer Aided Design Research. This paper has shown that

the parametric approach is one way to influence model flexibility, complexity

and information flow.