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Integration of computer graphics into building science
Henry, R. P.; Vanier, D. J.
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Ser
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1269
National Research
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by R.P. Henry and D.J. Vanier
ANALYZED
Reprinted from
Third Canadian Building Congress
Achievements and Challenges in Building
Science and Technology
Victoria, British Columbia, 18
-
20 October 1982
Proceedings,
p.
177
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182
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Division of Building Research
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1INTEGRATION OF COMPUTER GRAPHICS INTO BUILDING SCIENCE
R.P. Henry, Public Works Canada, Ottawa
D.J. Vanier, National Research Council of Canada, Ottawa
Computer d r a w i n g h a s been possible now f o r a m u p l e of y e a r s and t h e o p p o r t u n i t i e s for utilizing c o m p u t e r s h a v e a n t i n u e d to fasciriate system developers and potential u s e r s . Hiqh m s t s , unreliable equipment. and poor implementations have, until recently, led to disappointment in all b u t a few a r e a s . E a r l y e f f o r t s tried to i n c r e a s e productivity by seekinq o u t applications with many r e p e t i t i v e elements o r applications t h a t were within t h e limitations of t h e e a r l y equipment. Today t h e r e ace dozens of commercial s y s t e m s o n t h e market which o f f e r essentially automated d r a f t i n q , b u t l a r g e p r o d u c t i v i t y i n c r e a s e s
or
c o s t s a v i n g s with t h e s e s y s t e m s , a t least in t h e buildinq sciences, h a v e not been s u c c e s s f u l l y demonstrated.More r e c e n t l y , s y s t e m s h a v e been emerqinq t h a t attempt to wmbine t h e capability of w m p u t e r graphics a n d computer modelllnq with roles that t h e w m p u t e r has been offering in w n v e n t i o n a l a r e a s . It is in some of t h e s e applications, and t h e r e a r e many in t h e buildinq sciences, that much l a r q e r productivity i n c r e a s e s a r e possible; herein lies t h e q r e a t e s t f u t u r e for m m p u t e r qraphics in t h e building field. T h e
areas
w h e r e t h e g r e a t e s t advances a r e being made involve t h e integration of w m p u t e r m d e l l i n q with all a s p e c t s of t h e buildinq design p r o c e s s , specifically, where numerical t e c h n i q u e s a r e p r e s e n t l y being u s e d a n d also in t h e a r e a of planning a n d facilities manaqement. Associated with t h e s e applications, d a t a b a s e s c a n b e c r e a t e d t h a t a n t a i n not just t h e drawings but also physical r e p r e s e n t a t i o n of all buflding mrnponents. I t is this information t h a t can be manipulated and t r a n s f e r r e d by d e s i q n e r s . T h e potential impact o n e n g i n e e r i n g and a r c h i t e c t u r a l activities is enormous, b u t so too a r e t h e qains to be o b t a i n e d by t h e buflding i n d u s t r y .Le d e s s i n informatisk e s t maintenant possible depuis q u e l a u e s annkes e t les possibilitits dlutilisation d e s o r d i n a t e u r s w n t i n u e n t de fasciner les m n c e p t e u r s d e systkmes e t les Q v e n t u e l s utilisateurs. Jusqu12
t o u t rkcemment, les w Q t s Blev6s. le manque d e fiabilite du materiel e t d e s r6:ultats m g d b c r e s avaient c a u s k beaucoup d e deception, d a n s t o u s les domaines
A
quelques exceptions p r e s . Les premiers e f f o r t sant p o r t 6 s u r llauqmentation de la productivite par la r e c h e r c h e dlapplications 5 c a r a c t k r e rkpktitif ou d'applications a d a p t e e s a u x possibilites du materiel alors disponible. I1 e x i s t e a u j o u r d t h u i d e s dizaines d e syst&mes wmmerciaux permettant le dessin essentiellernent informatis6; o n nla toutefois pas e n c o r e d6montr6 d e m a n d r e p r o b a n t e les importan t e s augmentations de productivit6 e t ks Qconornies r6alisables g r l c e
3
c e s systemes, du m i n s d a n s la science du bstiment.Certains syst4mes mnCus plus r6cernrnent t e n t e n t d e w m b i n e r les possibilites d e l'infoqraphie e t de la modelfsation a v e c les s e r v i c e s s u e l'ordinateur o f f r e d a n s d e s domaines traditionnels. C1est d a n s c e r t a i n e s de c e s applications, et 11 en e x i s t e plusieurs d a n s la science du bstiment, q u e d e s a u q m e n t a t b n s de productivitk beaucoup plus i m p r t a n t e s sont possibles; ctest 1& q u e r e s i d e l'avenir d e ll{nfoqraphie dans l e domalne d\u bstirnent. Les plus q r a n d s p r o g r k s o n t Q t e rdalis6s q r s c e 2 l'int,&ration de la mad&lisation a tous les a s p e c t s du Processus de w n c e p t i o n d e s G t i m e n t s , e n p a r t i c u l i e r d a n s les c a s oC o n emplofe actuellement d e s techniques numeriques alnsi que d a n s les d o m d n e s d e la p l a n l f i c a t h n e t d e la qestion d e s installations. Parall6lement ces applications, on p o u r r a i t m e base de donnges m n t e n a n t non seulement d e s d e s s i n s , mais a u s s i d e s r e p r e s e n t a t i o n s p h y s i q u e s d e tous les Cl6rnents d e s hStiments. Ce Sont ceS donnges qui peuvent s t r e manipulkes e t t r a n s m s k s p a r les m n c e p t e u r s . Les e f f e t s possibles s u r 11inq6nierie e t l'architecture s o n t Bnormes,
Integration of Computer Graphics into
Building Science
R.P. Henry, Public Works Canada
D.J. Vanier, National Research Council Canada
Introduction
Computers are becoming far more
commonplace and influencing almost every activity in life today. Early users were predominantly involved in research activities and then, later, efforts were concentrated o n large scale business needs. Successful applications tended t o involve enormous numerical
calculation requirements o r the storing and sorting of large volumes of
tabulated data. More recently, considerable effort has gone into development of both hardware and sof tware which allows the creation and storing of pictures o r drawings. Early users of these CAD/CAM systems usually were large aircraft o r automobile manufacturers who could afford
substantial in-house expenditures on development of specialized systems for
their own use. Improved accuracies associated with automated design and manufacturing processes justified use of such systems. Now, other industries have recognized the advantages offered to them by CAD/CAM; in many cases design approaches impossible without the computer are' made available. A good example is the design of electronic parts and circuits with CAD/CAM systems.
Although the building industry uses drawings extensively, it has been rather slow t o utilize the computer's potential
in this area. This has been due t o quite a number of reasons, but principally it was a result of the fragmented nature of the industry, the fact that most businesses in the industry are relatively small, and the difficulty o f bringing together all of the diverse activities that make up the building sciences.
Th
is paperwill attempt t o review some of the developments to date in this area and demonstrate the potential for further progress based on experiences of Public Works Canada. Three broad areas will be
identified: intelligent drafting, building design and database systems; but first some consideration should be given to the benefits t o be obtained
from computer graphics.
Benefits of Using Computer Graphics Systems
In order to justify the large capital outlays associated with purchase and
installation of sophisticated computer graphics systems, consideration should be given to the benefits t o be
obtained. Often increased productivity alone is enough justification, but accurate cost/benefit figures are hard to pin down, due t o the relatively little experience in practice yet. Consideration, then, should be given to: 1. Increased Productivity.
Sometimes this is simply that two draftmen can now d o the work of four:
2. Better Products.
In one sense drawings produced are better because there is more
standardization. In a more far reaching sense, buildings produced are better since computer technique8 permit designers t o investigate more design alternatives.
3. Efficient Information Storage: Data used in design, such as material, equipment, o r engineering performance parameters can be stored in a
computer database, then retrieved instantly for design conaideration o r specification purpose8.
4.
Uore Consi8tent Quality.likely to be used. Drawings are easily corrected or updated, providing more accurate records of
construction features. A good
analogy is editing of word processor documents.
5. Shorter Construction Time.
Document production time can be greatly reduced, particularly if revision time is taken into
consideration. In addit ion, more
precise drawings result in better quality control which can reduce construction time considerably.
6. Better Coordination Between
Disciplines.
There is less potential for error and less duplication of effort if drawing files are instantly accessible to the various disciplines involved in design and construct ion.
Intelligent Drafting
The industry has seen, in the last couple of years, the introduction of many simple computer drafting systems. There are at least twenty to thirty different suppliers in the market today, thus making the business very
competitive. These are usually
described as two-dimenional, stand-alone systems and the prices range from
$60,000. to $120,000. per workstation, depending on the number of workstations purchased and whether plotting
facilities are included. Productivity claims are in the range of two to three for simple drafting tasks, but this depends greatly on the skill of users and the nature of the tasks. In choosing a system one should be very careful since suppliers are in the habit of preparing eye-catching demonstrations but neglect to describe to the potential purchaser specific pitfalls associated with his system.
One basic difference in systems is associated with
the
type of terminal-
raster o r storage tube(with
or withoutrefresh
capability). Although many usersseem
happy withthe
storage tubesystem, probably due to
the
extremelyhigh resolution that it offers, raster
systems have been improving and their
potential for displaying colour and moving objects a s well a a their quick
zooming
andredrawing
capability,if
used, can
be o f
considerable advantage-Also methods of input can vary
-
*thumbwheels, joysticks, or digitizer pads for cursor control are often
provided.
To
a large degree thechoice is one of personal preference, but the imprecise control offered by a joystick, which although relatively inexpensive, has often been cause for complaint.
Hardware is improving continuously, whereas only a couple of years ago breakdowns were commonplace, our experience has been that modern, carefully-selected hardware is greatly improved and should present relatively few problems to the user.
The potential user is more likely to experience greater difficulty with software. It may be crude and not suited to easy creation and manipulation of drawings or it may be full of "bugs" and use unsupported or third party supported software, or both.
Drawing functions performed by a
designer can be greatly simplified on a graphics system by combining repetitive construction steps into a single
operator command. This command, then, becomes a new tool in itself that can be used repetitively in a production
environment.
A designer should feel comfortable
working many hours at a time at his workstation. He should not have to abandon all of his drafting habits or become a sophisticated computer
programmer himself. Systems should be tested with the type of work that will be done on them before purchases are made. Jobs with a lot of repetition or that employ numerous "standard cellsn, that may be created before hand and stored, lend themselves nicely to computer-aided drawings.
Building Design with Computers Design is an iterative, evolutionary process. First, the overall layout is conceived, then further.deve1opment of thought allows the details to emerge, and finally, at some point in time, the design is said to be complete. This point may be somewhat arbitrary depending on such constraints as:
economics, time, and other commitments, to mention a few. Each designer in the process works on given requirements, prerequisites, and known information, communicating when necessary with fellow project designers. In a properly
authority is selected and a chain o f command is established based o n
conventional professional relationships. Finally, information in the form of specifications and drawings is produced t o transfer a description o f the desired product t o the construct ion operation. Throughout the above process w e s e e the usefulness and even absolute necessity' of drawings. First, for the designer t o concept ionalize his specific problem, second, t o communicate between designers in their cooperative design endeavours and finally, t o transfer specifications t o the construction phase.
For some time now individual
disciplines have been using computers t o perform certain portions o f the onerous
calculations o r repetitive procedures pertinent t o their design tasks. Perhaps the most extensive list o f examples may be found in structural engineering, but many others exist in such diverse fields a s energy analysis, 1 ight ing design, and accoust ical
analysis. Common are programs that perform simulations o f real situations in order t o evaluate the effects of different design choices. Few programs d o actual optimization o r provide final design solutions, rather the designer uses the program as a "tool" t o evaluate options and help him select the best design. Unfortunately, many o f these "tools" are cumbersome t o use and should be made more user-friendly with simpler
input and more descriptive output, perhaps utilizing graphics. As an example several organizations are now looking into the introduction of graphics t o some o f the major building energy analysis programs. Handbook
information, building geometric
parameters, and building and equipment performance characteristics, all might be presented instantly t o the designer for h i s review and consideration. He need not search through numerous handbooks o r previous files t o locate
information pertinent t o his specific immediate need, but simply recall t h e information, probably in graphical form, directly from the computer.
Models o f building components o r sub- assemblies such a s structural details, lighting layouts, o r HVAC ductwork can be created by individual disciplines. Subsequently, overlay o r three-
dimensional layouts are available t o these groups at various stages o f the design process t o ensure that
interferences are avoided.
The most repetitive aspect o f design, the detailing o f similar but slightly different parts, can be streamlined using the flexibility of the graphics system. A parametric model can be stored, replacing dimensions with parameters which may take o n specific values depending on size alteratives available. In the extreme, for
instance, it should be possible t o place a schematic for a heat exchanger on a drawing simply by stating certain flow rates and heat transfer requirements. In this way system design and drawings could be produced in very short time with little call for specializd drawing
skills.
The most sophisticated systems today allow creation o f 3-D files for objects which in turn offer viewing from any point with true perspective in wireframe
format. These may be used for anything from perspective views o f subdivision plot plans t o renderings of interior modular office concepts. Systems
automatically eliminate lines o r parts o f lines which would appear hidden from an observer, o r may include them a s dashed lines o r apply colours t o enhance visualization. Scale and colour can be changed instantly. These systems are prominent in CAM, parts modelling, o r piping design, however, 3-D modelling in the building field is relatively new and is not ready for general usage in most disciplines.
Building Data Bases
The building is composed o f millions o f components, all possessing many
important characteristics such a s specific heat, cost, density, size, standard dimensions, tolerances, etc. These are tied t o the building by some absolute physical location o r sohe relative location within a larger o r more important component.
A
multi- dimensional computer model then becomes the information shell o r the data base handler. Typically computer-aided building design is handled now through what are known a s application p r w r a m s . These serve s o m e disciplines very well, but d o not satisfy the majority o f t h epotential users. One of the reasons for
this 1s the requirement for each
discipline t o enter data that probably
has
been entered prev~ously In anotherdiscrete package. The majority of the time is spent enterlng data, which may add up to elghty percent of the time Ln front of a terminal. In the
conventional card-image input, columns have to be lined up, rows have to be numbered, and check routines have to be done over and over. This has been the most frustrating part of computer usage. The second most frustrat ing time is w a ~ t i n g for the results to be spewed out.
All of this will be changed with the new
generat ion of CAD. The computer-aided
designer inputs the general building shape that is based on a conceptual design. The outline, along with certain
information, is passed to the structural designer who lays out the column lines and does all the structural
calculations. At approximately the same
time the mechancia1,engineer may be
doing duct design or piping design. On completion of that task he will go to a load analysis o r energy analysis program to ensure the building is within the design prerequisites. The electrical designers may input their information
into the data base, as may the interior layout designers and the office
planners. Drawings, whether they be elevation or plan, are obtained only when hard print copies are required. Other benefits of the automated system
include quantity surveying or bill of materials, perspective or isometric drawings, and buildings specifications. As well as providing the coordination between disciplines provided by such a system, not to be overlooked is the continuity provided along the time path
associated with the product delivery.
.
As a example, building energy analysis considerations developed at the concept . stage can be elaborated upon later and
eventually turn up in details of the design of a mechanical System, or even provide input a s t o the way the building is finally t o be occupied.
Such a system may sound quite
futuristic, however, computer memory speeds and disk storage capacities are
increasing rapidly, making possible inexpensive storage and retrieval of vast banks of information. Problems
now are mainly associated with the structuring and sorting of this
information from the numerous
disciplines involved in the building sciences. A controlling data base is necessary that will manage information and share portions with each discipline. This management system is necessary to ensure that there is no conflicting information, that data need only be entered once, that problem information be automatically flagged and brought to the user's attention, and that overall control of the information, or changes thereof, can rest at specific design decision levels.
Building owners and operators will reap the greatest benefits from computers when a system provides a complete description and record of a building's history. In such a system both graphic and non-graphic informat ion are 1 inked in an all-inclusive data base. This offers great benefits at all stages of the design process where detailed characteristics, drawings,
specifications, codes, prices, etc. are created and carried as a by-product of the design generation. Subsequently, tabulated reports, such as bill of material lists, can be automatically generated from the design data base. At later stages this and similarly
generated information is invaluable for the process of renovating or managing the facilities.
In addition to the design process described above, Public Works Canada has become quite interested in the application of interactive computer graphics to what may be described as facilities management. Information would be stored and manipulated
similarly in each of three broad areas: land management, buildings management and occupant (both people and objects) management.
Types of useful information include: for Land Management,
-
site data and location withinjurisdiction boundaries,
-
property ownership data and boundarylocations,
-
utility data and locations, includingelements such as drainage characteristics, etc.,
-
area screening including permissable land use data with locations,-
tax data and locations ( i n PWC, municipal grants data),-
building administration data and locations;for Building Management,
-
building gross areas with designat ions a s t o usefulness, such a s building service areas, accessory areas, usable a reas,-
rentable area classifications and costs,-
further area designations o f usable spaces such as: workstations, support areas, circulation, special purpose areas, and building factors,-
breakdown o f occupants by function formanagement purposes,
-
location o f services and service equipment such a s lighting,electrical, phone, HVAC equipment, for Occupant Management,
-
furniture, room contents and any special equipment designated a s t o type and t o location,-
data representing actual names, titles, and functions o f people occuping o r controlling spaces,-
other information associated withpeople in spaces
-
such a s phone numbers, occupation periods, etc. ConclusionIn conclusion it must be stated that there is a vast potential t o apply interactive computer graphics in the building sciences. Turnkey systems available today, however, are aimed primarily only at t h e drafting
functions. In order t o get one's feet wet, s o t o speak, potential users should - b e aware that, even with these simple
drafting systems, investments are usually recoverable in less than t w o years. If a purchase is being
considered:
-
determine your requirements,-
consult users with similar operations and determine exactly what they are doing and not doing with their systems,-
be aware that vendors tend t o demonstrate there strong points andleave weaknesses for the purchaser t o uncover
,
-
ask for benchmarks o r demonstrations from identified vendors, looking particularly at responsiveness of the system, (It is especially important that the system always be able t o keep pace with the creative thought processes o f the operator. ):
look also especially at the vendor's product flexibility and support provided,-
ensure that the long-range goals o f your organization can be satisfied bythe vendor through upward compatability of his systems. In the future w e can expect t o see small, powerful graphics workstations networked t o large main-frame computers in order t o combine the advantages o f fast graphics with the benefits o f a shared data base. Communications will make it possible t o access drawings at many locations, even on-site in the
field. At this stage, effects o n the process of design and construction will be far more significant than the simple replacement o f manual drafting skills with automated drawing techniques.
