Digital Architectures

Computer Graphics for Architects in 2001-02 (Arch6025)

Marc Aurel Schnabel

Wednesday, 19 September, 2001

Introduction

“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.”

Ignasi de Sola Morales: 1997, Differences: Topographies of Contemporary Architecture, MIT Press, Cambridge.

Quotes

“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.”

Mitchell, W. and M. McCullough. (1995). Prototyping (Ch. 18). In Digital Design Media, 2nd ed., 417-440. New

York, Van Nostrand Reinhold.

Digital Architectures

Digital architectures refer to the computationally based processes of form origination and

transformations. Several digital architectures are identified based on the underlying

computational concepts such as

i. topological space (topological architectures)

ii. isomorphic surfaces (isomorphic architectures)

iii. motion kinematics & dynamics (animate architectures)

iv. keyshape animation (metamorphic architectures)

v. parametric design (parametric architectures)

vi. genetic algorithms (evolutionary architectures)

Digital Fabrication

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.

i Topological architectures

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.

Guggenheim Bilbao by Frank Gehry

ii Isomorphic Architectures

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.

Cardiff Opera by Greg LynnBMW-Pavilion by B. Franken

iii Animate Architectures

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.

House in Long island by Greg Lynn

Kinematics

Port Authority Bus Terminal in NY by Greg Lynn

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.

iv Metamorphic architectures

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.

Offices of BFL Software ltd. by Peter Eisenman

v Parametric Architectures

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.

algorithmic spectaculars by M Novak

vi Evolutionary architectures

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.

“pseudo-organisms” by J. Frazer

vii Virtual Environments

The use of computer modeling and simulation to enable a person to interact with an artificial

three-dimensional visual or other sensory environment. VR applications immerse the user in a

computer-generated environment that simulates reality through the use of interactive devices,

which send and receive information and are worn as goggles, headsets, gloves tracking devices,

CAVES and other media.

Immersive VE

viii Rapid Prototyping

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.

CNC

Bernard Cache’s “Objectiles”

Gehry’s "Zollhof" in Duesseldorf

Bernard Franken’s "BMW Pavilion"

Movies

Open folder “movies”

End

• Tonight @ 18.30: Guest Lecture by Prof. Neil Leach

• Next week 26.09.10: Digital Tools

• Two weeks 03.10.01: Topological (i) & Isomorphic Architectures (ii)

• Three weeks 10.10.01: Animate (iii) & Metamorphoric (iv) Architectures

• …

Wednesday, September 19, 2001; marcaurel@hku.hk