behavior-based computational design...

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integration through computationacadia 2011 _proceedings

W i th t he i n t r oduc t i on o f phys i cs -based a l go r i t hms and mode l i ng env i r onmen ts ,

des i gn p rocesses have been sh i f t i ng f r om the r ep resen ta t i on o f ma te r i a l i t y t o t he

s imu l a t i on o f app rox ima te ma te r i a l desc r i p t i ons . Such compu ta t i ona l p rocesses

a re based upon enac t i ng phys i ca l and ma te r i a l behav i o r, such as g r av i t y, d r ag ,

t ens i on , bend ing , and i n f l a t i on , w i t h i n a gene ra t i ve mode l i ng env i r onmen t . Wha t

i s o f t en l ack i ng f r om th i s s t r a t egy i s an ove ra l l unde rs t and i ng o f compu ta t i ona l

des i gn ; t ha t i n f o rma t i on o f i nc reas i ng va l ue and p rec i s i on i s gene ra ted t h rough

t he deve lopmen t and i t e r a t i ve execu t i on o f spec i f i c p r i nc ip l es and i n t eg ra t i ve

mechan i sms . The va l ue o f a phys i cs -based mode l i ng me thod as an i n f o rma t i on

eng i ne i s o f t en ove r l ooked , t hough , as t hey a re p r ima r i l y u t i l i z ed f o r deve l op i ng

r ep resen ta t i ona l d i ag rams o r s t a t i c geome t r y – i nev i t ab l y t r ans l a t ed t o f unc t i on

ou t s i de o f t he phys i ca l bounds and pa rame te r s de f i ned w i t h t he mode l i ng

p rocess . The de f i n i t i on o f compu ta t i ona l des i gn p rov i des a l i n k be tween p rocess

and a l a rge r app roach t owa rds a rch i t ec tu re – an i n t eg ra t i ve behav i o r-based

p rocess wh ich deve lops dynam ic spec i f i c a r ch i t ec tu r a l s ys tems i n t e r r e l a t ed i n

t he i r ma te r i a l , spa t i a l , and env i r onmen ta l na tu re . Th i s pape r, f ocus i ng on ma te r i a l

i n t eg ra t i on , desc r i bes t he r e l a t i on o f a compu ta t i ona l des i gn app roach and t he

t echn i ca l f r amewo rk f o r a behav i o r-based i n t eg ra t i ve p rocess . The app l i ca t i on

i s i n t he deve lopmen t o f comp lex t ens i on -ac t i ve a rch i t ec tu r a l s ys tems . The

ma te r i a l behav i o r o f t ens i l e meshes and su r f aces i s i n t eg ra ted and a l go r i t hm ica l l y

ca l i b r a t ed t o a l l ow f o r comp lex geome t r i es t o be ma te r i a l i z ed as phys i ca l s ys tems .

U l t ima te l y, t h i s r esea rch p roposes a compu ta t i ona l s t r uc tu re by wh i ch ma te r i a l and

o the r so r t s o f spa t i a l o r s t r uc tu r a l behav i o r s can be ac t i v a t ed w i t h i n a gene ra t i ve

des i gn env i r onmen t .

Behavior-based Computational Design Methodologiesintegrative processes for force defined material structures

Sean Ah lqu is t

Stu t t ga r t Un i ve r s i t y

Ach im Menges

Stu t t ga r t Un i ve r s i t y

Ha r va rd Un i ve r s i t y

ABSTRACT

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1 Introduct ion

Arch i tectura l des ign processes have long re l ied upon means of representat ion to

produce des ign so lut ions. In contemporary methods, the media for representat ion

is pr imar i ly geometry – depicted in a d iscrete number of e lements (po int , l ines,

sur faces, etc. ) , the i r f in i te pos i t ions, and the i r associat iv i ty. The re la t ion to mater ia l i ty,

manufactur ing, assembly, and operat ion is of ten appl ied – a f lex ib le def in i t ion to which

vary ing these proper t ies does not have d i rect impl icat ions on the geometry format ion.

Subsequent s imulat ion models serve to ass ign speci f ic i ty, ver i fy, ra t iona l ize or s imply

nu l l i fy mater ia l , s t ructura l , or env i ronmenta l systems impl ied by such des ign geometr ies.

The t rend in in tegrat ive const ra in t-based des ign processes is to address the inc lus ion

of speci f icat ions wi th in the des ign geometry through geometr ic and mathemat ica l ru les;

a l lowing cr i t ica l proper t ies to not be exc lus ive on ly to the s imulat ion model (Mark,

Gross, and Goldschmidt 2008). Whi le th is prov ides a f ramework for i te rat ive geometry

generat ion, i t does not address the inc lus ion of processes which s imulate in tegrated

behav iors which are of ten too complex for s imple mathemat ica l and associat ive ru les.

A s imulat ion model , by def in i t ion, is not of s tat ic condi t ions, but ra ther an encapsulat ion

of processes (Weinstock and Stathopolousos 2006). In deta i l , the ‘model ’ def ines the

complete stat ic and dynamic character is t ics which dr ive the in terna l capaci t ies and

externa l condi t ions in f luencing the loca l and g loba l ar rangements. S imply stat ing the

proper t ies and c lass i f icat ion of the e lements wi th in the des ign geometry does not

account for how the e lements in f luence each other, and most important ly in manners

that are not h ierarch ica l ly pred ictab le. Associat iv i ty, in terms of s imulat ion, is not a

d iscrete re la t ionsh ip; ra ther i t is a process, in i tse l f , which def ines how e lements

behave ind iv idua l ly and co l lect ive ly. Form is ak in to the ‘model ’ – the in format ion and

repercuss ions of behav ior through i ts re la t ion to context .

In a behav ior-based approach, the def in i t ions of the e lements themselves inc lude

the processes, in instances of manufactur ing const ra in ts, dynamics in assembly, and

in f luences of operat ion. Form resu l ts f rom the reso lut ion of the var ious behav iors – in

geometr ic pos i t ion, and associat ion, as wel l as in the in format ion which def ines a

par t icu lar s tate. The inc lus ion of in format ion as a resu l t o f a s imulat ing process re la tes

a behav ior-based approach more in t imate ly to the s imulat ion model . In arch i tecture,

th is may be most ev ident in Fre i Ot to ’s approach towards des ign through the s imulat ion

of mater ia l behav ior in sca led form-f ind ing models. Ot to ’s soap-f i lm exper iments are

sca led mater ia l s imulat ions ut i l i zed to mimic and test fu l l -sca le system behav ior (Ot to

1990). The most immediate t rans lat ion of th is is in the use of F in i te E lement Ana lys is.

Whi le c lear ly not an ef f ic ient des ign too l , the log ic of FEA, though, has been taken in to

the des ign rea lm through phys ics-based computat iona l model ing programs such as

Axe l K i l ian ’s CADenary sof tware, a lso re fer red to as CatenaryCAD (Chak et a l . nd) . The

des ign env i ronment, through act ivat ing spr ings as in formed mater ia l force e lements,

prov ides rap id s imulat ion for the form-f ind ing of hanging cha in models.

Resul t ing f rom th is process of des ign s imulat ion is in format ion beyond mere geometr ic

pos i t ion which makes a d is t inct connect ion to fur ther computat iona l ly in tense and

numer ica l ly accurate s imulat ion models. The des ign in format ion a lso fa l ls more acute ly

in to be ing c lass i f ied as a des ign model , fo l lowing the t ruer def in i t ion of ‘model ’ : the

dataset which houses processes and e lements ind icat ing the in terna l systems which

organ ize the des ign and externa l in f luences that def ine the ent i re ty of the arch i tecture.

In the a l ignment of process, mater ia l i zat ion and funct ion ing, behav ior-based des ign

enve lops a conceptua l , computat iona l , and pract ica l understanding of arch i tecture as

form, which can be pro jected f rom a mater ia l system to system of systems – a mater ia l ,

spat ia l , and operat iona l gesta l t .

2 Systems and Computat ion

The term system, in the context of arch i tectura l form and pract ice, serves as a

synthes iz ing concept by which the arch i tectura l system ( form) can be seen as an

in tegrated, spat ia l and mater ia l dev ice, where i ts des ign is generated ( in pract ice)

by a computat iona l system of a lgor i thmic mechanisms operat ing to reso lve in terna l

and externa l per format ive cr i ter ia . Computat iona l ly, the methods need not mimic

computation, formation and materiality

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the dynamics of the ent i t ies and env i ronments that are be ing produced. One is a

generat ing, eva luat ive, feedback dev ice; the other, a dynamic operat iona l mater ia l and

spat ia l form (A lexander 1968). Cr i t ica l to an in tegrat ive v iew of the arch i tectura l system

is understanding that the computat iona l systems which s imulate in tegrat ive behav ior

are in format ion generat ing dev ices whereby in format ion is cont inua l ly expanded and

exacted. Th is is the on ly way in which in tegrat ion (behav ior ) can be reso lved, through

the evo lut ion of increas ing speci f ic i ty, ra ther than in the sor t ing of pre-determined data

(knowledge) or on the foundat ions of genera l i zed assumpt ions.

In most arch i tectura l pro jects, the ear ly des ign stage is decis ive in determin ing a

bu i ld ing’s eventua l per formance (K impian et a l . 2009). However, few des ign too ls

and methods, purposed for ear ly s tage des ign, have been deve loped to address the

complex i ty of in teract ions amongst mater ia l e lements and predict re la t ionsh ips to the i r

env i ronment. The task is evermore grand when env i ronment is def ined as not on ly a

ser ies of c l imat ic condi t ions but as d i f ferent ia ted s i tuat ions of occupat ion, and spat ia l

qua l i ty. Two pr imary modes have emerged as processes for generat ing such arch i tectura l

systems. The f i rs t is a method of “d iv ide and conquer” where systems are segregated,

opt imized and deal t w i th in re la t ive iso la t ion, a combinat ion of top-down organizat ion

of the whole, and bot tom-up in the format ion of the ind iv idua l systems (L igget t et a l .

1992). The second is a systems behav ior-based approach where the form is rea l i zed

in the process of in ter re la t ing mater ia l and spat ia l condi t ions (Weinstock 2004). Th is

computat iona l process ut i l i zes fundamenta l pr inc ip les of phys ica l proper t ies, a l lowing

bas ic in i t ia l speci f icat ions (s t i f fness, e last ic i ty ) to be re layed in to behav iors of how

mul t ip le e lements in teract (under tens ion, compress ion, pressure, grav i ty, etc. ) .

I te rat ive deve lopment, a t f i rs t , estab l ishes the pr inc ip les of var ious system aspects.

Subsequent ly, i te rat ion serves as a par t o f a feedback funct ion to a l low for increas ing ly

par t icu lar speci f icat ion and eva luat ion. The d is t inct ion and d is tance between the in i t ia l

form generat ion and the fu l ly speci f ied system in operat ion is min imized.

Examin ing mater ia l and comput ing i ts react ions to in ter re la ted condi t ions, phys ica l ,

c l imat ic and socio log ica l , pos i ts the des ign process as an i terat ive ef for t o f gather ing,

coord inat ing, compar ing, re-generat ing and most important ly speci fy ing in format ion.

Gather ing cons iders def ined and adjustab le leve ls of computat iona l mater ia l pred ict ion,

invest igated through phys ica l and computat iona l exper iments. Th is in format ion can be

packaged wi th in the constants of the computat iona l process, though in themselves

act ing as determin is t ic processes not invar iant va lues or equat ions. Coord inat ion

means the synchron izat ion of in format ion wi th methods of measure. Compar ing and

re-generat ing act ivates i terat ive feedback. Speci fy ing means a search for increas ing

accuracy of in format ion f rom in i t ia l abst ract , s imple pr inc ip les, log ics, and mathemat ica l

parameters. The “d iv ide and conquer” method tends to re ly upon precedence, or a

knowledge-based approach, where prev ious stud ies prov ide speci f icat ion up f ront in

the des ign process. In th is case, in format ion is recompi led rather than formulated.

Th is is an awkward imposi t ion on the des ign process in that such speci f ic i ty may not

reg is ter the un iqueness of a par t icu lar context or mater ia l resources.

Th is br ings up a fundamenta l d is t inct ion in the approach towards computer-

based des ign in arch i tecture. Terz id is s tates th is c lear ly in the d is t inct ion between

computer izat ion and computat ion. The former, imply ing a t rans lat ion to the computer,

ass imi la tes ana log processes of the gather ing and organ izat ion of wel l - formed

in format ion in to automated procedures to der ive a resu l t . The la t ter, imply ing a making

of and f rom comput ing processes, executes re la t iona l means which induct ive ly and

deduct ive ly in form speci f ic so lut ions (Terz id is 2003). The most bas ic understanding of

a funct ion ing system is one which operates through leve ls of deve lopment, feedback

and redeve lopment (Ber ta lanf fy 1969) in search for a par t icu lar homeostas is. In th is

sense, a computat iona l approach connects the complex nature of arch i tectura l des ign

more c lose ly to the rea l izat ion and operat ion of arch i tecture as the mani fest of a

behav ior-based generat ive system for rea l i z ing h igh ly speci f ic systems.

3 Computat ional Behavior

Address ing a behav ior-based computat iona l approach towards the des ign of force-

act ive mater ia l s t ructures (o f ten categor ized as l ightweight s t ructures) is a log ica l

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appl icat ion. Th is is pr imar i ly because there are no s imple mathemat ica l equat ions

which can descr ibe the ent i re ty of a sur face def ined by the equi l ib r ium of appl ied force

– be i t tens i le , compress ive, or pressur ized. The wel l -known examples of phys ica l

form-f ind ing by Anton i Gaudi and Fre i Ot to depict a process by which phys ica l

s imulat ions produced forms representat ive of pre-st ressed st ructures. In Ot to ’s soap

f i lm exper iments, the mater ia l generated sur faces wi th equal ized force d is t r ibut ion in

tens ion – a geometry which could be matched at fu l l sca le wi th tens ioned text i les.

Gaudi ’s hanging chain models repl icated mass, gravi ty, and topology to generate a tensi le

structure representat ive of a geometry that could be inverted to work as a compression

only structure. With ei ther of these methods comes a t r icky t ranslat ional step. There is no

di rectness in the s imulat ion between study model and physical structure. As ment ioned

previously, the most l i tera l br idge between form-found geometry and simulated structure

is through the use of F in i te Element Analysis. Pr ior to computat ional means, force-

act ive structures ut i l ized exhaust ive scaled simulat ions intended to be exact in thei r

mater ia l character ist ics and structura l behavior, fo l lowed by hand calculat ions to analyze

addit ional loading (Moncr ief f 2005). F in i te Element Analysis a l lev iates th is need through

al locat ion and simulat ion of a wel l-def ined model, a c lear example of a knowledge-

based process. As such, FEA si ts outs ide of a computat ional design approach, not only,

obviously, in i ts demand for speci f ied geometry, mater ia l , and contextual def in i t ions, but

in the fact that i t has a s ingular goal in resolv ing the, a lbei t complex, structura l behavior

of the pre-stressed and loaded system.

Axe l K i l ian most notab ly in t roduced a computat iona l approach for form-f ind ing and

model s imulat ion wi th the research and deve lopment of h is CADenary sof tware.

Whi le st i l l a form of representat ion – a “hanging” pure tens ion model which could be

inver ted to funct ion as a compress ion-on ly s t ructure – K i l ian def ined a methodology

us ing Par t ic le Systems which a l lowed for the approx imate s imulat ion of a phys ica l

hanging cha in model (K i l ian and Ochsendor f 2005). W i th in a par t ic le system, a par t ic le

def ines a po int mass, whi le a spr ing acts to apply tens ion or compress ion forces

between connected par t ic les. Grav i ty is act ivated to create the hanging cha in form

wi th a ser ies of in terconnected par t ic les and spr ings (wi th the spr ings act ing on ly in

tens ion) . Beyond the poss ib i l i ty o f i te rat ive and cumulat ive methods of des ign (a lways

a s ign i f icant cha l lenge in any phys ica l form-f ind ing method) , the model ing env i ronment

based upon fundamenta l pr inc ip les of behav ior a l lows for the phys ica l and in tegrated

nature of a compress ion-on ly des ign to be invest igated.

CADenary was deve loped us ing the programming env i ronment Process ing. Th is

fact should be cons idered as inc lus ive to the computat iona l des ign process: the

deve lopment of a un ique yet specia l i zed model ing env i ronment. The computat iona l

system is not complete ly un iversa l – s imply captur ing the fundamenta ls of the hanging

cha in model , yet a l lowing for complex invest igat ions to take p lace. Other capaci t ies

wi th in the des ign env i ronment of fered poss ib i l i t ies to expand the st ructura l invest igat ion

of the system, act ivat ing grav i ty in a l ternat ive vectors to test the stab i l i ty o f a g iven form

Fig. 1

Figure 1. Diagram for behavior-based

computational design process


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and programming const ra in ts for fabr icat ion (K i l ian 2004). Whi le K i l ian packaged these

concepts, techniques and technolog ies as sof tware, the ent i re ty of the deve lopment

process, more compel l ing ly, evokes a f ramework for the des ign of the computat iona l

process as wel l as i ts act ivat ion: deve lopment of process pr inc ip les, s tud ied through

generated mater ia l i zat ion, and accumulated in to a speci f ic computat iona l model ing

env i ronment – a l l executed to d iscover new pr inc ip les in the targeted compress ion-

on ly s t ructura l -mater ia l system. Th is sat is f ies the condi t ions of a computat iona l

approach as one d i f ferent ia ted f rom an approach based on pre-packaged processes to

one which focuses on a ‘meta-des ign’ o f fundamenta l behav iors and pr inc ip les (Coons

1963). The in ter- looping process coord inates fundamenta ls d iscerned f rom phys ica l

and computat iona l exper iments, act ivated wi th in an i terat ive generat ion and feedback

process, u l t imate ly augmented wi th prec ise model s imulat ion (F igure 1) .

4 System Complexity

Look ing pr imar i ly a t force-act ive tens i le s t ructures, there is a par t icu lar cha l lenge in

recogn iz ing the d is t inc t ion between the behav io r o f tens ioned meshes (cab le nets ) and

tens ioned sur faces ( tex t i l es o r membranes) wh i le reg is te r ing the d i f fe rences w i th in the

computa t iona l f ramework . A fundamenta l d is t inc t ion l ies in the mater ia l i za t ion between

a mesh and a sur face fo r tens ion-act i ve sys tems. A mesh is compr ised o f a ser ies

o f ind iv idua l e lements connected together w i th f i xed nodes (F igure 2 ) . A sur face is

de f ined by f ibers wh ich a re essent ia l l y over lapp ing in two pr imar y d i rec t ions, de f ined

as the warp and wef t . In per fo rming aga ins t a tens i le load, a sur face w i l l a lways

look to d is t r ibu te the fo rces as even ly and equa l l y as poss ib le . Force is reso lved

across the ent i re sur face, though w i th in f luence o f va r iab les between the warp and

wef t o f the tex t i l e const ruc t ion. For a mesh, fo rce is reso lved ind iv idua l l y w i th each

node. Th is means tha t a mesh can rea l i ze a more va r ied se t o f morpho log ies ( fo rm,

topo logy, and tens ion behav io r ) , bu t poss ib ly resu l t ing in h igh-degrees o f va r ia t ion

in the fo rce in tens i t ies across the who le sys tem. Th is is not a lways a prob lem, but

can resu l t in va r ied per fo rmance aga ins t add i t iona l load ing such as w ind, o r va r ied

degradat ion o f mater ia l (Lewis 2003) . These a re c r i t ica l cond i t ions to cons ider in

tens ion-act i ve sys tems, but can be reso lved in parameters o f topo logy and feedback

f rom s t ruc tu ra l s imu la t ion.

What is necessary to note in the process of des ign generat ion, when qual i fy ing the

mater ia l d is t inct ions stated above, is the degree of var ia t ion in tens ion d is t r ibut ion

across the spr ing topology. As stated, tens ioned meshes can be accompl ished wi th

essent ia l ly any topolog ica l ar rangement of spr ings. Th is can be reg is tered numer ica l ly

wi th in the re la t ive va lues that the tens ioned spr ings return wi th in the Par t ic le System

env i ronment. I t can a lso be measured by the degree of curvature. An idea l ly tens ioned

geometry is ant ic last ic (doubly-curved) wi th a Gauss ian curvature of zero. The degree

Figure 2. Mate r ia l i za t ion and var iab le

computa t iona l topo logy fo r f i xed mesh

Figure 3. Mate r ia l i za t ion and s t r ic t

computa t iona l topo logy fo r woven tex t i l e

Figure 4. Var ious aspects o f tens ion-act i ve

sys tem behav io r

Figure 5. Trans la t ion f rom geomet r y and

fo rce descr ip t ion to un- tens ioned 2D templa te

fo r fabr ica t ion

Fig. 2

Fig. 3

Fig. 4

Fig. 5

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of double curvature in the geometry wi l l ind icate the degree of tens ion, where less

curvature means a more in tense moment of tens ion (Kn ippers et a l . 2010).

For tens ioned sur faces, the topology of spr ings is more const ra ined. The goal is to

s imulate the b i-d i rect iona l nature of a text i le const ruct ion to where forces wi l l a lways

tend to d is t r ibute across the ent i re system of connected e lements. Representat ion of

the over lapping f ibrous behav ior of a woven mater ia l would be incredib ly computat iona l ly

in tense. W i th a f ixed topology of spr ings that reg is ters the warp and wef t d i rect ion of a

text i le ( l i ke the U and V d i rect ions of a sur face) , the b i-d i rect iona l nature of how tens ion

d is t r ibutes can be approx imated (F igure 3) . There are of course p lenty of var iab les

wi th in th is to invest igate complex ar rangements of in terconnected tens ioned sur faces.

Double curvature, aga in, is a character is t ic to measure. Though, un l ike the ab i l i ty

to manipu late every e lement ind iv idua l ly wi th in the topology of a tens ioned mesh,

curvature wi th in a tens ioned sur face can on ly be cont ro l led by vary ing parameters

between the sets of U and V spr ings, and a l ter ing the boundary condi t ions.

What becomes ev ident in deve lop ing and execut ing a behav ior-based des ign process

is the accumulat ion of in format ion beyond that of s tat ic geometry. Whi le Par t ic le

Systems, outs ide of the work descr ibed prev ious ly by Axe l K i l ian, have been ut i l i zed

as form-f ind ing engines, the weal th of in format ion that can be resourced is of ten

over looked – geometry be ing the pr imary and s ingu lar mot ive. W i th in a Par t ic le

System, a spr ing is ca lcu lated fo l lowing Hooke’s Law of E last ic i ty. Th is states that

a force can be determined by a spr ings degree of d isp lacement f rom i ts rest length

( rest length is the moment at which a spr ing exer ts no force) (Gordon 2006). Whi le

th is does not account for non- l inear behav ior, i t does prov ide an approx imate and

re la t ive descr ipt ion of forces as they move through a par t icu lar tens i le topology. Th is

can be usefu l for understanding, as ment ioned before, var ia t ions in force d is t r ibut ion.

U l t imate ly, i t prov ides an in t imate oppor tun i ty and feedback for invest igat ing the

inext r icab le re la t ionsh ip between topology, force, and form. The accumulat ive va lues

of force at the boundary condi t ions a l low for force in tens i t ies and force vectors to be

v isua l ized at the points where the system anchors to secondary st ructures (F igure 4) .

Generat ing form is as much about manipu lat ing and eva luat ing force in format ion as i t

is about negot ia t ing topology and geometry.

A p ivota l po int in eva luat ing the system behav ior as an in format ion model is the necess i ty

for coord inated in format ion of force, topology, and geometry for mater ia l i zat ion. In

th is case, mater ia l i zat ion should be cons idered in terms of generat ing ver i f icat ion

models ( for the system pr inc ip les) and mock-ups. By no means does the ‘systems

behav ior ’ por t ion of the process generate thorough and accurate enough in format ion

to produce components for fu l l sca le const ruct ion. Such is the process descr ibed

inc lud ing ‘system s imulat ion ’ as the log ica l s tep towards product ion and fu l l -sca le

assembly. In deve lop ing sca led models f rom the Par t ic le System in format ion, the key

aspect is understanding e last ic i ty. W i th the use of e last ic mater ia ls for model ing,

double curvature can be accompl ished. At arch i tectura l sca le, e last ic i ty is min imized

to the point that each e lement is broken down in to s ing ly curved geometr ies (L inhard

2009). W i th a h igh ly e last ic mater ia l double curvature in tens ion can be accompl ished

f rom a f la t un- tens ioned sheet . Trans lat ing f rom a doubly-curved geometry to th is f la t

sheet cannot be done by a s imple geometr ic ‘unro l l ing ’ a lgor i thm. But , by inc lud ing

the in format ion of force and the geometr ic deve lopment (F igure 5) , a par t icu lar spr ing

topology can be s imul taneous ly unst ressed and unro l led to determine i ts f la t 2D

template (F igure 6) .

In execut ion, th is behav ior-based computat iona l process cont inua l ly produces

in format ion which reverberates between phys ica l s imulat ions, computat iona l

generat ion of mater ia l behav iors, and s imulat ion of speci f ic parameters and mater ia l

def in i t ions. I t o f fers a d is t inct def in i t ion for the meta- f ramework and ind iv idua l

processes for computat iona l des ign. In pract ice, th is has enabled the examinat ion of

tens ion-act ive systems as in tegrated ce l lu la r mesh and sur face systems. Work ing f i rs t

wi th phys ica l form-f ind ing stud ies to exact bas ic ce l l def in i t ions, the computat iona l

s t ra tegy is const ructed to express the ce l ls as spr ing topolog ies (F igure 7) . From

both a des ign and computat iona l perspect ive, inev i tab le complex i ty can be managed Figure 6. Torus component fabricated as

tensioned textile from behavior-based model

Fig. 6


88


through an ef for t where des ign var ia t ion occurs pr imar i ly through topology var ia t ion. As

the spr ings form-f ind force equi l ib r ium, the descr ipt ion of geometry is not an expl ic i t

des ign task. Geometry is par t o f the in format ion that resu l ts f rom the manipu lat ion

of topology and reso lv ing of force d is t r ibut ion. The pr imary topology of an ind iv idua l

component in th is research is that of a cy l inder. Such a fundamenta l organ izat ion can

be eas i ly t ransformed to s impler topolog ies such as a p lane or more complex ones

such as in terconnected cy l inders or toro ida l ar rangements (F igure 8) . Through i terat ive

steps of model generat ion and t rans lat ion to phys ica l mock-ups, a cont inua l expans ion

of the in t r icacy, topology and geometry complex is pursued (F igure 9) .

5 Conclusion

Computa t ion has broken in to the rea lm o f o f fe r ing the poss ib i l i t y to mimic methods

o f des ign s imu la t ion as opposed to des ign representa t ion. Form- f ind ing, in i ts

most l i te ra l (and h is to r ica l ) de f in i t ion is the sca la r dete rmina t ion o f fo rm th rough

the rep l ica t ion o f rea l wor ld contex tua l and mater ia l cond i t ions. The fami l i a r mode ls

o f Anton i Gaud i , F re i Ot to and o thers a re the foundat ion fo r computa t iona l des ign

s imu la t ion processes. Axe l K i l i an , w i th th is CADenar y so f tware , and the va r ious

phys ics-based eng ines, such as Kangaroo, Nuc leus fo r Maya, and Traer Phys ics ,

o f fe r an adapt ion o f these prev ious phys ica l mode l -based processes. But they do

not o f fe r a comparab le f ramework when des ign computa t ion de lves in to the rea lms o f

cons ider ing mu l t ip le des ign fac to rs , and the necess i ty fo r genera t i ve des ign i te ra t ion

to dete rmine e f fec t i veness between var ious c r i te r ia .

Th is research has focused on in i t i a t ing pr inc ip les o f mater ia l and s t ruc tu ra l behav io r

to enact an in tense but i te ra t i ve computa t iona l des ign process. Th is encompasses

a vas t l y in tegra t i ve v iew o f des ign process wh ich inc ludes the synchronous

deve lopment in fo rming the meta- f ramework , the programmed behav io r-based

processes, and the i te ra t i ve t r igger ing o f the des ign genera t ing sys tem, The sys tems

based approach beg ins to reg is te r a d i rec t , no t representa t iona l , connect ion towards

a v iew o f a rch i tec tu re as dynamic in i ts response to mater ia l resources, behav io rs ,

and contex tua l input . Wh i le the s tud ies f rom th is p rocess focus on the deve lopment

o f complex tens ion-act i ve sys tems, and pr imar i l y the i r potent ia l fo r complex

morpho log ica l descr ip t ion, the f ramework can be expanded to env is ion an even more

in tegra t i ve v iew o f a rch i tec tu re . Where complex behav io rs can be computed f rom

s imp le pr inc ip les , the e f fo r t o f in tegra t ion becomes an expans ion o f the ‘p rocess

constants ’ – the eng ines wh ich def ine ind iv idua l behav io r and produce in fo rmat ion

to reso lve co l lec t i ve behav io r. Computa t iona l des ign re l ies upon the spec i f ic i t y and

i te ra t i ve coord ina t ion o f p r inc ip le behav io rs ; a s ign i f icant sh i f t f rom des ign processes

wh ich funct ion upon co l lec t i ve genera l i za t ions and organ iza t ion o f p reconce ived

fo rma l s t ruc tu res and in fo rmat ion.

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