THE REPRESENTATION OF SURFACE CONSTRUCTIBILITY

SURFACE CONSTRUCTIBILITY

THE REPRESENTATION OF SURFACE CONSTRUCTIBILITY

Muhammad Farihan Irfan Mohd Nor, Azimin Samsul Mohd Tazilan, Abdul Halim Ismail,

Ismar Minang Satotoy Usman

¹Architecture Department,

Faculty of Engineering, Universiti Kebangsaan Malaysia,

43600 UKM Bangi, Selangor, Malaysia.

E-mail: [email protected]

Tel: 00603 8921 6844/6299 Fax: 00603 8921 6841 INTRODUCTION

It is important for us to identify the types of surface forms that form most of today’s

contemporary architecture, from the simplest form of building to the more complex

form of buildings like the Guggenheim Museum in Bilbao, Spain. In studying these

surface forms, the writer focuses more on Frank Gehry’s works, as his works are

known for it’s revolutionised form and high usage of CAD. The development of

Frank Gehry’s buildings’ surface forms produce a very big impact towards the

development of the buildings’ building systems and determines the aesthetic value

that has so long been adored by people around the world. This of course comes with

the building envelope systems that endorse the forms design.

However, these design forms were not created overnight and did not come out of the

blue but were the result of years of development and innovation. Progressive

developments of the forms were made whenever each of the projects was completed;

they were analysed and became precedents to forthcoming projects where selected

elements were extended and developed creatively. This development can be seen

through the different set of forms, but same architectural language, as from Gehry’s


earlier projects such as his Residence to the more recent projects like the Walt

Disney Concert Hall in Los Angeles.

The study presented in this topic discusses the types of geometric forms and simple

analysis of the forms of contemporary buildings and issues that come with it. This

forms design study will also offer an insight into the constructability requirements in

computational forms.

PLANAR SURFACES

The first category of forms to be discussed is the simplest of all and has been the type

that most building forms around the world adopt. However, this form, which is

called ‘Planar Surfaces’ for it’s characteristics of flat, straight and very limited

Euclidean geometries have very high geometric constraints (Figure1). These

constraints can be exemplified through the physical modelling of these surfaces

where rigid pieces of material - mounting board or foam board - can be cut,

positioned and glued together in a space to form a planar shape. The actions of these

unbending sheets of material are enabled and also constrained to planar shapes

because of its own characteristics of rigidness, stiffness and inflexibility. Though

non-planar shapes such as spheres can still be made using the same material sheets, it

can be a very difficult task and the end product may not be as intended.

Figure 3.1a – Earlier Projects like the Steeves House mainly consists of Planar Surfaces


Planar forms, which are known to have been used for centuries for building designs,

have a construction system that is relatively simple to understand. There are many

construction systems that are based on the planar form. Somehow this type of form

has been accepted by our mind now, principally because planar construction systems

have been the most logical and simple, making them easy to understand by everyone.

In this way of thinking, even if rigid sheets of material were made into a physical

model comprising compilation of planar objects, one would be able to understand or

assume the behaviour of these modelling materials and relate the planar compilation

to a real world construction system.

The mathematic descriptions for planar surfaces, which are Euclidean geometries,

are very simple and precise thus making it the simplest form that can be generated in

CAD modelling applications, be it a high-end application like CATIA or a more

traditional application like the earlier versions of AutoCAD, Form Z or 3D Studio

MAX.

As for that, the limits of planar forms, that respect the constraints of planar geometry,

can be explored easily by using these mathematical descriptions or by simple

engineering understanding. As planar forms are constructed orthogonally, the

spreading of loads of the building forms can be more easily predicted and

understood, and somehow does represent the real building construction. This simple

and rigid mathematical constraint system also has a clear affinity with the fabrication

system whereby straight planar elements could be fabricated easily using standard

requirement.

As in most of the works of contemporary architects such as Frank Gehry, Daniel

Libeskind, Peter Eisenmann, Nicholas Grimshaw and ZDR Architects, planar forms

are a big part of their designs especially in their early works such as Gehry’s resident

project in California, Grimshaw’s Sainsbury Superstore and Eisenman’s Biocentrum.

However the usage of planar forms in these architects’ designs were not readily

noticed for the material, as people were much more interested in their distinguished


“paper surface” forms and free forms, which will be discussed later in this topic. In

the case of Frank Gehry, one can still see, nevertheless, that planar forms are being

implemented throughout his building projects from the early Edgmar Development

in Santa Monica, California to the Stata Complex at the Massachusetts Institute of

Technology. These simple forms have been used on Frank Gehry’s building projects

as a way to cut cost, as these geometries are clearly less expensive to construct and

uses a conventional construction method. This, in a way, alongside the use of

CATIA, has allowed Frank Gehry to meet project programmatic requirements within

the budget set by the clients.

However, still, these planar forms were then explored and developed to create more

ambitious planar forms as the development of his building forms went on. His early

building designs show this exploration. According to Shelden (2002)31

” The radical proposition or “violence” of this early work is precisely in its

demonstration that conventional, industrial materials and constructions

could generate unconventional forms, applied unconventionally to non-

industrial architecture programs”.

“FREE FORM” SURFACES

A “free form”, with its name clearly representing its characteristics, is a total

opposite form of surface class to the planar surface. A “free form” is an

unconstrained surface geometry that has no rules and limits as far as shape geometry

is concerned. As mentioned in the previous sub-topic that a planar surface could be

represented through a rigid sheet material made model, a “free form” could be

represented through plasterseen or clay made model.

This type of surface form is very flexible as how easy it is to shape clay into any

intended forms. If a planar physical model could give indications towards the type of


construction system supporting planar forms that range from stud framing to glass

curtain walls to concrete framework one can also do the same with “free form”

surface. However for this, the types of construction systems that might be

considered would be moulded systems such as cast metal or concrete, or even

stamped technologies used by aviation fabricators.

The Zouk Club in Kuala Lumpur by ZDR Architect, Eden Project at Cornwall,

England by Nicholas Grimshaw, Green Umbrella by Eric Owen Moss and Esplanade

Performing Arts Center in Singapore by DP Architects, are clear examples of how

free form surface is applied to buildings. Noted that these buildings are all built

within the last 10 years and are considered by many as the latest trend in building

design. Though the art novou era that dominated much of Europe before World War

II possess similar characteristics, most of the buildings during that time only use

concrete mouldings to create the free forms.

Looking back at about 30 to 40 years ago, there is no geometric description for this

kind of irregular form. It does not have any specific mathematical descriptions to

describe it. At that time, there are only basic mathematic descriptions for

representation of specific but simple canonical shapes such as spheres and helices.

Any architect who has work since then must surely still remember, that for any

architecture or structure design, the only curves that were applied to geometric

representation were curves that were generated from the use of French curves and

ship splines which is, of course, not entirely accurate.

However, this scenario has changed with the development of computers and

software. According to Al Dean (2003)24 during the 1970’s, Bezier, Coons and

others have developed curved descriptions specifically for the purpose of digital

representation. These descriptions seemed to form the basis of contemporary CAD

systems of today. Today, thanks to the development and application of CAD, many

architectural firms have fully benefited from the use of CAD programmes especially


in dealing with free form surfaces. Now we would have the capabilities of accurate

representation of irregular curved surfaces.

However, even though this type of surface is now considered unconstrained surface

geometry, and could achieve accurate mathematical and geometric representation

through CAD, it still has some other considerable constraints, such as high costs, the

difficulty in producing the moulds necessary for casting and fabrication, cost of

labour and expertise, and complexities in describing these shapes mathematically as

discrepancy between digital and physical renditions of form are too great.

”Although these modelling techniques provide tremendous power and

flexibility in representing many curved surface geometries, they are still

constrained by their mathematical definitions. These functions can be used to

cast curved surface representations over sampled spatial data. But in

between this spatial data, the surface formulations assume forms guided by

their own functional characteristics. Tighter conformance to digitized data

from physical forms requires additional information, as well as additional

computational complexity of the surface description and associated user

interaction”.

Shelden (2002)31

The surfaces of the

Conference Centre, DG Bank

at Pariser Platz are made of

Free Form surfaces


This shows that in the case of Frank Gehry, where digitising the physical model is

part of the design process, there are some problems in between the process of

digitising those models representing the “free forms” and generating its geometry in

CAD. These CAD representations of the physical object still needs to be rectified, to

remove the defects in the physical object and to simplify or rationalize the digital

geometry to a form that can be further developed or manipulated. Based on this we

could understand that this is where it becomes complicated, as NURBS surfaces do

not read like planar surfaces. The structuring of NURBS surfaces is very different

from physical clay structuring which opposes to planar surfaces. Shelden (2002)31

also added that, apart from these considerations, the digital structure of the free form

geometry in CAD does not have a relationship with the features and behaviours of

real physical materials. This may result in generating two same forms; a digital

geometry form and a physical model, but with different structural qualities.

All the above explains why truly free form shapes, which could be constructed

through CNC driven moulded or stamped fabrication technologies, were not often

applied to building projects. The difficulties stated above make the whole process,

although achievable through the usage of high-end CAD applications like CATIA

and the CNC, very expensive and less practical.

PAPER SURFACES

The final category of general surface forms is the one that sits in between the highly

constrained planar surfaces and the unconstrained “free forms”, described in the

previous sub-topic. By virtual of its name, this general class of curved surface forms

are forms that can represent the characteristics of paper sheets material. Thus, this

class of forms were called by Frank Gehry as paper surface or sheet material surface

(Jim Glymph, 2001)31. To understand these forms, it can perhaps best be described

by simply constructing a simple physical surface by bending a flat, flexible sheet


material such as a photocopy paper and assemble this surface into a simple closed

form. Of course, we could assume that trying to model a “free scale” shape like

spheres using sheet materials would be very unpractical, although some could argue

that it could come close to being made into a sphere, but still there would be some

wrinkling or even ripping of the sheets.

These characteristics of paper surfaces allows the shape to have more freedom

compared to the highly constrained planar Euclidean shapes and at the same time,

quite constrained and having more control compared to the free forms surface. This

class of surface form was excessively applied to nearly all of Frank Gehry’s projects,

especially on more recent projects, and can be considered as being part of his

buildings’ identity. Other buildings that are characterized by paper surfaces are

Novou Club in Kuala Lumpur by S.I Design, Cincinnati Country Day School by

Greg Lynn, Glasgow Science Centre by BDP Architects and Spectrum House by

gm+ad Architects.

Through scale physical models made of sheet materials, to a great extend these paper

surface forms show clear affinity to the same sheet material used in real scale

construction. According to Shelden (2002)31, a paper sheet like form does have

analogue constraints similar to many materials of fabricated construction elements.

A scale curved structure element, which might be formed into curved shapes in space

like steel mesh, are considered to have the paper surface characteristics if it does not

apply stretch forming.

Again, shapes that are formed from flexible sheet materials have a clear affinity

towards the condition of the material. This is somehow different from planar

Euclidean geometries, as these shapes, which are formed by rigid materials, seem to

be more independent of the actual material of construction. In this respect, material

plays a big role in both ‘paper surface’ physical model and full scale construction.

The constraints that the materials possess give an indication to the constraints it


would impose on the building systems. An example of this would be the cladding of

surfaces with sheet materials, overlapping shingles systems and welded metal back

pan systems.

The qualities of materials, such as stiffness and brittleness, have huge effects on the

quality of the surfaces of paper surface shapes deformed using these sheets of

material. Apart from that, the material thickness and forming activities will also

have an effect on the behaviour of these materials. The use of titanium, stainless

steel or aluminium panels all possess different qualities from each other. For

example, a thinner titanium panel can be stronger and resistant to ductile deformation

compared to thicker aluminium panels or stainless steel. However, as to be more

economical, stainless steel has been used widely and more often in buildings shaped

by paper surface forms.

Paper surfaces, though the constructability is not as highly constrained as “free form”

surfaces, still possess very high constraints when compared to planar Euclidean

surfaces. The constraints of paper surfaces are to some degree characterized by the

shape of the surface assembly, the material and the manner in which these sheets are

attached together, as it responds to externally applied forces and actions. This is

partially because sheet materials have limits on the magnitude of deformation they

can respond to.

Considering all the above factors of the complexity of its systems formal constraints

and the fact that paper surface shapes are an essential part of this new type of

architecture, there is quite a demanding need for CAD modelling within the

architectural firms that carries paper surface forms as their architecture identity. This

is because the flexibility and intuitiveness of the real physical surface material does

not present a clear affinity with the geometric controls and operations of a digitally

constructed paper surface. As for this, the process to generate the geometry into

digital form from the physical paper surface model needs to be done carefully, with

very high precision, adding information and more rectification processes, thus

needing many CAD experts and becoming very time consuming.


However, still it is through the extensive use of CAD that paper sheet surfaces can be

well described and explained in the project documentation thus allowing it to be fully

realized. As in the case of Frank Gehry, it is the use of CATIA, which is a high-end

CAD application originally used for aviation that has resulted in the creation of free

flowing structures such as the Guggenheim Museum at Bilboa and Experience Music

Project at Seattle.

CONCLUSION

The above categories of surface forms have its own characteristics that give different

characters to buildings around the world. However, these three categories do in a

way reflect the depthness in the usage of CAD in a building’s delivery process as

every each category’s reliance on CAD differs vastly. As described above, free forms

or paper surface forms needs high definition CAD application to assist in design

processing and also documentation and as far as Malaysia is concerned, not many

architect firms have high definition CAD application due to its high costing and also

lack of expertise.

Thus, this constraint is imposed on most building projects by limitations of

traditional documentation. The complexity of determining geometric relationships

between more complex, non-Euclidean forms is simply beyond the capabilities of

Figure 3.1c – Design process

model shows Paper Surfaces of

the unrealized Samsung

Museum of Modern Art, in Seoul,

Korea, 1995

Paper Surface Forms has been

the main surface geometric for

the Guggenheim Museum in

Bilbao, 1991-97


traditional architectural delineation. As for that, the limits imposed by digital

representation present a substantial constraint on the inclusion of forms in the design

vocabulary.

However, what we can learn from these architects who have developed their design

strategies in applying free forms or paper surface forms is that how this has granted

them the freedom to design without having any constructability constraints. The

introduction of free forms and paper surface forms into their design piece, with the

assistance of high definition CAD application, has lifted their names within the

architectural world and now setting up a new architectural trend that is envied by

others. The issue here is not about which category of surface forms reflects better

architecture but it is about lifting the constructability constraints that has so long

bound architects’ freedom of design.

REFERENCES Muhammad Farihan Irfan Mohd Nor: (2003), Frank Gehry’s Process: Digitally

Adapted, Masters Dissertation, University of Strathclyde; United Kingdom.

Bruce Lindsey: (2001), Digital Gehry: Material Resistance and Digital

Construction, Birkhauser Publishers for Architecture; Italy

Dennis Shelden: (November 19, 2002), The Digitally Integrated Building Delivery

Process of Gehry Partners, Concurrent Sessions: Case Studies — An In-Depth Look

at Applications Capitalizing on Digital Construction Conference

Al Dean: (2003), Catia V5 Release 10, http://www.cadserver.co.uk; London

Steele, James: (2001), Architecture and Computers, Laurence King Publishing;

London


Adam Aston: (Dec 2, 2002), A 'MAGIC METAL' FOR THE MASSES Stronger,

lighter, cheaper--titanium comes of age; Business Week, New York

Gordon Wright: (May 2000), Compounding the curves, Building Design &

Construction; Chicago

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THE REPRESENTATION OF SURFACE CONSTRUCTIBILITY