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Prepared forThe Foundation of Wall and Ceiling Industry

ByWords & Images

BIM is here to stay.

Steve Jones, McGraw-Hill

The real promise of BIM lies in its application across the entire project team, especially in the area of improved building performance.

Technology Industry Analyst, Jerry Laiserin

Get the habit of analysisanalysis will in time enable synthesis to become your habit of mind.

Frank Lloyd Wright

2009 Foundation o the Wall and Ceiling Industry. All Rights Reserved.

No part of this publication may be reproduced in any form by any electronic or mechanical means, including information storage and retrieval

systems without permission in writing from the publisher.

Published by

Foundation of the Wall and Ceiling Industry

513 West Broad Street, Suite 210

Falls Church, VA 22046-3257

(703) 538-1600

July 2009

Building Information Modeling:Understanding and Operating in a New Paradigm

www.awci.org/thefoundation 1


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Preace

Fi f W Cii IsIn the late 1970s, there was a clear recognition among industry leaders or the need to unite and expand

the educational and research activities available to contractors, manuacturers, distributors and the public,

in general. At the time, there were many issues acing the industryrom a national energy crisis to injuries

in the workplace, to unsae buildings occupied by the public. In response to these issues, the Foundation othe Wall and Ceiling Industry was ormed in 1977 with the ollowing mission statement as an IRS designated

non-prot 501(c)3 corporation to pursue educational and research activities beneting the industry and the

public at-large:

The Foundations mission is to be an active, unbiased source o inormation and education to support the

wall and ceiling industry.

To ulll this mission, the Foundation owns and maintains the largest independent library serving the wall

and ceiling industry, provides educational scholarships or those pursuing careers in engineering, construc-

tion and design, provides research support to industry inquiries and publishes research papers.

To obtain additional copies o this publication or to learn more about the Foundation o the Wall and Ceiling

Industry, please contact

Foundation o the Wall and Ceiling Industry

513 West Broad Street, Suite 210

Falls Church, VA 22046-3257

Phone: (703) 538-1600

Fax: (703) 534-8307

E-mail: [email protected]



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Executive Summary 7What Is Building Inormation Modeling? 7B I M Pro j e c t I n v i t a t i o n s o r S u rv i v a l 7The Future o BIM 72020 8

Conclusion 8

An OverviewBIM 9The Players 9

3-D Modelers 10Autodesk/Revit 10Bentley 10Vico 10Tekla 10

Viewers/Surace Modelers 10Google-SketchUp 10NavisWorks 10

Analyzers 10Energy+ 10

DAYSIM 11ApacheSIM 11LieCycle 11

Obstacles to BIM 11It IsBroke 11Training Curve 11Cost o Sotware 11

What Drives the Use of BIM? 11The Bottom Line 11Fragmentation 11Inefciencies 12Waste 12Cost 13

A Problem Solved 13Green Buildings 13Energy Analyses 13Communication 13

The Power of BIM 14Virtual Building 14

Parametric Objects 14Coordinated Design Model 14

2-D Documentation 15Version Control 15Preabrication 15Analysis Tools 15

Clash Detection 16Constructability 16Structural 16Perormance 16

Energy 17Acoustical 17Lighting 17

Estimating 17Building Element Models (BEM) 18

The buildingSMART alliance 18Industry Foundation Classes (IFC) 18

Table f Cs

4 Foundation oF the Wall and Ceiling industry


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Architects and Engineers 19Design Process 19Team Design 19Big Room 20What IsAnalyses 20

Levels o Detail 20

General Contractors 20

Subcontractors 20Preabrication 21Clash Detection 21Take-o and Estimating 21

Wall and Ceiling Contractor 21Take-o and Estimating 21Clash Detection 22V i su a l i z a t i o n /C o m m u n i c a t i o n 2 2Preabrication 22Scheduling 22

Sound and Light Analysis 22Constructability 22Inormation 23Project Management 23BIM Project Invitations 23

Facility Managers 23

Risks: Legal & Contracts 23The Thorny Part 23Risks in the Adoption and Use o BIM 23

Behavioral Risks 24Technology Related Risks 24Defnitions 24

BIM Legal Impact 24

Risk and Reliance 25Risk Allocation 25Ownership and Reliance 25

Current Framework/BIM Perspective 27Liabilities 27Risks 27Rewards 28Intellectual Property Rights 28Suggested BIM Contract Language 28ConsensusDOCS 301BIM Addendum 28General Principles 28Defnitions 29Inormation Management 29BIM Execution Plan 29Risk Allocation 30Intellectual Property Rights in Models 30Conclusion 30

The Future of BIM 312020 31Conclusion 31



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BIM is not just the

latest release of

CAD software; it is

an entirely new

way of looking at

the design and

construction of a

building.

ExecutiveS

What IS BuIldIng InFormatIon modelIng?Building Inormation Modeling (BIM) allows you to

ully and truly construct a building virtually, and in

detail.

During the BIM-design phase you can not only select

and place the materials that will make up the nishedstructureincluding concrete slabs, rebar, steel struc-ture, wall and ceiling components, HVAC, plumbing

and electricalbut you can also test all such parts

or conficts (clash detection) to ensure everything

will come together seamlessly. And all this while you

can still use an eraser, rather than having to rework

later in the eld.

You can also use this 3-D building model to analyze

the designed buildings energy eciency by running

what i scenarios to determine the best o several

potential solutions. In addition, depending on the de-

tail o the model, you can automatically take o allitems contained in the model and that way produce

an impressively precise estimate.

The sotware and database management technologyexists today to accomplish exactly this. What has yet

to be realized and bought in to by a large majority o

our industry, however, is the degree o collaboration

and coordination between the various construction

disciplines that BIM calls or.

Not only the owners and architects, but engineers,

contractors and, ideally, subcontractors as well, needto be involved in the project rom the outset; in oth-er words, during the design o the building. This, o

course, invariably means some orm o design-build

rather than the currently prevailing design-bid-build

process.

BIM is not just the latest release o CAD sotware; it

is an entirely new way o looking at the design and

construction o a building.

Many quarters are hailing BIM as the panacea to

most, i not all, construction industry ills, solving

both design and construction problems while alsoproviding a complete as-built 3-D building model as

a property management acility upon completion o

the project.

Those who have already taken the BIM-leapwhetherarchitects or contractorsreport that they already seesignicant benets, and savings, with BIM technol-

ogy and processes; a reported reduction to near-zero

job RFIs (Requests or Inormation) and in-the-eld

change orders speaks or itsel.

Those who claim that BIM has yet to enter prime timealso have a point in that there are still many issues

to be resolved; chie among them being the question

o interoperability among various BIM sotwares, the

learning curve involved in implementing BIM, and

the necessary paradigm shit in how buildings are

designed and constructed.

Although, as it stands today, the wall and ceiling in-dustry is not greatly involved with BIM, there is no

question that sooner rather than later, owners, de-

signers and general contractors will begin to invite

and bring only BIM-enabled subcontractors into

their projects, and it would serve the wall and ceil-

ing contractor well to become amiliar with this new

technology and this new way o building.

Opinions notwithstanding, BIM is moving orward.

Several high-visibilities projects, such as the FreedomTower in New York City, are BIM-designed and con-

structed. While it may still be on the horizon or most

o AWCIs membership, BIM is approaching rapidly.This paper aims, thereore, to arm AWCI contractors

with the knowledge and understanding they need to

ace a BIM uture protably, and with certainty.

BIm ProjeCt InvItatIonS or SurvIvalAs BIM gains more and more traction, general con-

tractors will increasingly look or BIM-enabled sub-

contractors.

Thereore, as a rst step, the wall and ceiling con-

tractor should learn all that he or she can about the

technologyand the processand decide how hisor her company ts into the BIM picture.

Once he or she has become amiliar with, and now

can work within a BIM-ramework, the next crucial

step is to make this abilitythis additional service

known ar and wide. Advertise it, print it on your

business cards and ensure all your GCs know: You

are BIM-enabled.

the Future oF BImTo quote technology industry analyst Jerry Laiserin,

The real promise o BIM lies in its application across

the entire project team, especially in the area o im-proved building perormance.1

To date, BIM has oered only glimpses o what 3-D

modeling, and the requisite team spirit to make it

work, are capable o. As more government agencies

like the General Services Administration speciy BIM

in their contracts, as more benets surace, and as

more owners seeand sharehigher prots, BIM willnd ull traction and will reshape the industry. It is

not a question o i, it is a question o when.



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By 2020 BIM will

most likely have

reached all the

way into the

building codes

structure and the

permits process.

The contractor or subcontractor who gears up now

or at the least ully inorms him- or hersel about whatBIM can do or his or her company, or how a BIM-

enabled company might better serve the industry

will soon be in high demand. Those who eel that the

boat is doing just ne and should not be rocked may

nd themselves scrambling or BIM tools and rushinginto perhaps ill-advised choices once BIM becomes

a general requirement, be it or economic, green orother reasons.

The important thing to realize is that BIM, at heart, is

not just sotware but a human activity that ultimatelyinvolves broad process changes in construction.2

2020By 2020 BIM will most likely have reached all the

way into the building codes structure and the per-

mits process. Send me the model, may well be the

immediate response to a permit request. More likely

than not, the permit oce now has an analyzer that

will quickly (in a matter o seconds) veriy that yourmodel is to code, and you may receive your permit

in days, rather than weeks, ater submittal.

Lean Construction principles will have worked their

way into a majority o projects, and the U.S. construc-tion industry will, as a team-centric industry, be the

most productiveand the most proudin the world.It does not take a crystal ball, or even 20/20 vision,

to see that.

ConCluSIon

Building Inormation Modeling has grown out o itsinancy. The day the GSA required all o its contracts

to be BIM-based signaled the moment.

BIM may mean many things to many people. It is a

buzzword, to be sure, but it may be on or o the ra-

dar or the wall and ceiling subcontractor o today.

But BIM, both as mature sotware and as process,

has in act arrived, and regardless o cost or learn-

ing curve, its benets have been proven to outweigh

its drawbacks.

The smart subcontractor will take heed.



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A correctly

assembled BIM is a

reliable, digital,

three-dimensional,

virtual

representation of

the project to be

built, for use in

design decision-

making.

Anoiw

Although the concepts and methodologies we now un-derstand as Building Inormation Modeling date back asar as 30 yearsand then primarily within the manu-acturing and aerospace industries, BIM as a design andconstruction term was introduced about 15 years agoto set the then-emerging, inormation-rich, architectur-

al computer-3-D modeling apart rom traditional, andmainly paper-based, 2-D design and drawing.

BIM aimed to designate both a sotware approach anda method o designing and constructing a building bythe use o highly coordinated and internally consistentcomputable inormation about the building; all the wayrom conceptual design, through construction, to post-construction and asset management.

A correctly assembled BIM is a reliable, digital, three-dimensional, virtual representation o the project tobe built, or use in design decision-making, in construc-

tion document production, in construction schedulingand planning, in perormance predictions and in costestimates. Keep in mind that, as with all other com-puter-based applications, the quality o the output isalways limited by, and does refect, the quality o theinputyouve no doubt heard the term garbage in,garbage out.

With what in essence is a three-dimensional represen-tation o a centralized database containing all itemsthat will comprise the actual buildingincluding theirlocation, dimension, relation to other items, composi-

tion, cost, as well as their ordering or manuacturingdetailsthe owner, architect, engineer, contractor, sub-contractor and manuacturer have a clear view o theproject as a whole, in one up-to-date and integrateddigital environment.

The model, again assuming all input is correct, willprovide the builder an easily assimilated view o theentire picture, its interrelations, and o any positionalconficts and problems. And most importantly, it willalso provide the inormation and the understandingnecessary to resolve positional conficts and other is-sues during the design phase, rather than later, on the

building site.

These potential benets notwithstanding, many orga-nizations are still taking a wait-and-see attitude aboutBIM, waiting or the proverbial jury to return.

Needless to say, or BIM sotware vendors, the jury isback, and has been or a while: BIM is the answer.

This sentiment is echoed by most consultants as well,andincreasinglyby those early adopters who have

implemented BIM and its processes on their projects.These include the U.S. General Services Administration,Disney and Intel.

The consensus among those who have actually used

BIM (and with that the jury is beginning to return to

their seats) is that BIM saves both time and money,

sees ewer conficts and design errorsalong with

a drastic reduction in RFIs and change ordersandimproves productivity.

BImThe 3-D images o BIM are no longer surace-only

shapes. They are objects.

They are objects with content. The wall contains

studs at indicated intervals; it contains wallboard o

a certain thickness. The concrete slab contains rebar

to increase tensile strength. The windows are double-glazed (or not).

I all database elds (parameters) pertaining to a givenobject are correctly populated, you can nd out every-thing you need to know about any given item, including,among other things, its position and relation to otheritems, its R-value, its manuacturer, its cost, its placeo manuacture, its use o recycled material, and itsdelivery timeeven its installation instructions.

You can look at a true (meaning all pertinent inormationis accurately entered) BIM rendering and know as muchabout what you are looking at as i you were lookingat the real thing, in real time. And you can understand

the BIM 3-D model so much better than a 2-D drawing,because you see it as it is supposed to look.

BIM has many other strengths, but this one is key: BIMtruly acilitates communication and understanding.

BIM acilitates communication between the ownerand the designer and between the designer and thecontractor, who now sees how it all goes together, andwho can be assured through clash detection that therewill be no conficts; and between the contractor andthe subcontractor, who also gains a much better un-derstanding o what, exactly, is to be done rom the

clear visual that BIM oers.

the PlayerSThe eld o BIM players breaks down into makers othree distinctly dierent sets o tools:

3-D modelers.Viewers/Surace modelers.Analyzers.

The 3-D modeler is the true BIM tool, working with



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Analyzers are

normally third-

party software

that speaks to the

main BIM tool,

meaning it can

import and then

analyze data from

the 3-D modeler to

determine the

models energy

efficiency or

daylighting, among

other things.

solid, parametric objects in sucient detail to virtuallyconstruct the building.

Not all views o the project have to be in that detail,

however. The nancing entity may want to see what

the building will look likeas may the owner

and or that all you need is a surace modeleror a

viewerto which all shapes are hollow. All it knows

about is suraces, which is all it needs to recognizein order to show concepts, and detect clashes or in-

stance, and as such is o tremendous value.

Analyzers are normally third-party sotware that

speaks to the main BIM tool, meaning it can import

and then analyze data rom the 3-D modeler to de-

termine the models energy eciency or daylighting,

among other things.

3-D ModelersAlthough there are several additional 3-D modelers

on the market, these are our o the main players at

this time:

Autodesk/RevitBy all accounts this is the most widely used o the

BIM tools, primarily since Autodesks AutoCAD has

or several years now more or less ruled the auto-2-D

drawing market and Revit Architecture appears to bea natural extension o thatwhich it actually is not.

Revit was originally a startup, acquired by Autodesk

and introduced as Autodesk Revit in 2002. Revits

platorm is completely separate rom AutoCAD, both

as to code and le structure.

Bentley SystemsBentley Architecture, introduced in 2004, was an

evolution o its earlier platorm, TriForma.

Several other Bentley modules integrate well with

Bentley Architecture:

Bentley Structural.

Bentley Building Mechanical Systems.

Bentley Building Electrical Systems.

Bentley Facilities.

Bentley Power Civil.Bentley Generative Components.

With these modules, Bentley addresses almost all

aspects o the AEC industry.

VicoWhile Vico is a new company, its BIM engine is basedon the almost venerable Graphisot ArchiCAD. Gra-

phisot sold ArchiCAD to a German sotware devel-

oper in 2007, while it at the same time spun o the

ArchiCAD-based construction suite to Vico sotware,

a new company ocusing on the design and construc-tion industry.

The engine, ArchiCAD, has been a solid modeler sincethe mid-1980s, and is now a very stable platorm.

Other modules in this suite include project man-

agement, Estimator, and Project Control, which is ascheduling sotware.

TeklaTekla is a Finnish sotware house ounded in 1966

that specializes in structural steel, steel reinorcing

in concrete, and precast concrete modeling. In this

area, the sotware is capable o taking a design all

the way rom concept, through design and structure

analysis, through detailing, all the way into produc-

tion and assembly. Thereore, you can use the same

model created at the outset o the project or preab-

rication output.

Viewers/Surface ModelersA viewer/surace modeler builds its model entirely

on surace dimension. A box will have six sides, all

o which will be incorporated as adjoining planes,

but as ar as the sotware is concerned, the box con-

tains nothing.

Google-SketchUpOriginally, SketchUp was developed by @Last Sot-

ware, and has, ever since, due to its ease o use and

aordability, taken the design community by storm.

Google purchased SketchUp a while back, and it ap-pears to be a good match.

NavisWorksThis tool is a viewer o models; that is its mission.

NavisWorks has developed links to virtually all BIM

modelers on the market, and so can import, say, a

plumbers 3-D model along with an HVAC 3-D model

or the purpose o clash detection.

Like SketchUp, NavisWorks will also allow you to rap-idly put a surace modeled design together or com-

munication purposes.

AnalyzersAnalyzers are those reestanding sotware programs

that specialize in importing BIM data rom modelers orpurpose o simulations and analysis. There is a widearray of these players in the field, such as these:

Energy+EnergyPlus is now the primary sotware tool used orenergy perormance analysis o commercial buildingsby the Department o Energys Building Technologies



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Even those trained

in CAD today need

to step back and

realize that this is

something new.

This is not CAD+,

or Son of CAD. BIM

is its own approach

and its own

discipline. Any

time spent now to

master this

approach will be

time (and money)

well spent.

Program. Developed in 1996 by DOE, EnergyPlus is anew generation building energy-simulation program

that builds on the most popular eatures and capa-

bilities o BLAST and DOE-2.

DAYSIMDAYSIM is a daylighting analysis sotware that cal-

culates the annual daylight availability in arbitrary

buildings as well as the lighting energy use o auto-mated lighting controls (occupancy sensors, photo-

cells) compared to standard on/o switches. Among

the dynamic daylight perormance metrics calcu-

lated by DAYSIM are daylight autonomy and useul

daylight index.

ApacheSIMThis analysis sotware enables you to assess every

aspect o thermal perormance, rom annual energy

consumption and carbon emissions down to individualsurace temperatures. ApacheSim is at the core o theIES suite o thermal-analysis products, each o which

simulates an aspect o thermal perormance: solarshading and penetration (SunCast), HVAC systems

and control (ApacheHVAC) and natural ventilation

and mixed-mode systems (MacroFlo).

LifeCycle

NREL (National Renewable Energy Laboratory) and itspartners created the U.S. Lie-Cycle Inventory Data-base to help lie-cycle assessment experts answer theirquestions about the environmental impact o materi-als used in building industry and other industries. Thedatabase provides a cradle-to-grave accounting o the

energy and material fows into and out o the environ-ment that are associated with producing a material,component or assembly. Its an online storeroom odata collected on commonly used materials, productsand processes.3

Obstacles BIm

I BIM be such an elixir or all construction-industry ills,why hasnt there been a stampede in its direction?

There is movement it its direction, to be sure, but it

cannot be deemed a stampede by any stretch.

It IsBroke

We cannotawash in RFIs and change orders, andwith substantial contingencies budgeted as a mattero course or any given projecthonestly say that thestatus quo is working smoothly and should be let aloneto its own devises.

As Willem Kymmell puts it in Building InormationModeling, his study o the subject, Despite many re-

cent developments in project delivery methods, own-ers are oten still dissatised with the results o theconstruction industry; projects still take too long andcome in over budget, while the quality requently isnot up to the clients expectations.4

That is not a description o all is well. More likely, itdescribes a situation that deserves improvement.

traInIng Curve

Once a designer or a contractor has bought into theconcept o BIM, the next thing to aceand this ismore important than the cost o needed sotware andhardwareis the learning curve.

Even those trained in CAD today need to step back andrealize that this is something new. This is not CAD+,or Son o CAD. BIM is its own approach and its owndiscipline. It warrants and requires serious, and pos-sibly lengthy, study to become procient in the ins andouts o the tools, but any time spent now to master this

approach will be time (and money) well spent.

CoSt oF SoFtWare

The nal obstacle to ace is the actual cost o the sot-ware and necessary hardware to run it. BIM toolsdo not come inexpensively, and it may all outsidethe budgetary realities o a smaller rm. Possibly amake-break point as ar as implementing some aceto BIM with in-house sotware and personnel, is 100or so employees.

Firms smaller than that can still benet rom BIM by

participating in team meetings, and possibly outsourceany required model construction to BIM consultants.

Whatdis h us f BIm?

the Bottom lIneThe strongest driver o all, and no surprise here, is thenotorious bottom line. From an owners perspective,business as usual, in its design-bid-build modewithits inherent inecienciesis simply becoming tooexpensive.

BIM saves him money.

FragmentatIonIn a typical, traditionally designed and run project, theowner retains an architect who, through conceptualschematic design, design development and contractdocuments, delivers to the owner an understanding oprecisely what he wants the architect to build.

Once they reach an agreement and sign contracts,the architect then normally hires consultants to help



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An accurate BIM

can avoid lost time

by catching and

displaying

scheduling

conflicts before

you even break

ground, making it

possible to address

and solve these

problems before

any time is lost.

design the structural, HVAC, electrical, re-rating andplumbing components o the job.

Now, the structural engineer is interested in the in-tegrity o the structure. The HVAC team cares aboutHVAC; plumbing and electrical, same boat. They eachproduce a set o designs and plans depicting their ownparticular universes, which then have to be coordinated

to avoid the most obvious conficts.

Keep in mind that all plans at this point have to bedetailed enough to serve as bid documents or sub-contractors; although the architect, perhaps to avoidliability, says conventional wisdom (so the drawingsdo not come back to bite them)will insert languageto the eect that the architectural drawings cannot berelied upon as to dimensional accuracy.

Still, general contractors will now bid or the job, asdrawn. The general contractor in turn will send draw-ings out to bid by the relevant subcontractors, and based

on which subs are chosenand prices quotedthegeneral can then submit a nal bid to the owner.

Once a general contractor has been awarded the job,but beore work can begin, the winning GC may haveto redraw some, or all, o the plans to refect the ac-tual construction process (sequence o events, avoid-ing conficting subcontractors crews, etc.), which willproduce general arrangement drawings.

At this point, most subcontractors and abricatorssince the dimensions and details o the bid documents,

as a rule, are not guaranteed to be accuratewill thenproduce their own shop drawings, which must refectaccurate details o the work to be perormed. Theseshop drawings are then sent to the architect or approv-al. Then the architect will typically approve them asnoted with sel-serving stamps attempting to disclaimliability should problems be encountered later.

Any errors in these shop drawings, or in the originaldrawing on which they are based, will invariably suraceas costly conficts and rework in the eld, as whenorexampleboth plumbing and electrical discover thatthey, in act, do not have exclusive rights to a particu-

lar duct space, which now has to be redesigned andenlarged, on the fy, to make room or both.

IneFFICIenCIeS

U.S. government statistics show that between 1964and 2000, United States manuacturing productivitydoubled, while, over the same time span, the construc-tion industrys productivity declined by 80 percent.5

True, buildings have become much more complex, andrarely are any two construction projects the same or

conducted by the same players, which is hardly everthe case in auto manuacturing, or example. Nonethe-less, such a drop in productivity can hardly be seen asencouraging news.

Maged Abdelsayed o Tardi, Murray & Associates, aconstruction company located in Quebec, Canada,compiled a revealing set o numbers to illustrate just

how complex a construction project can get.

For any large-scale projects ($10 million or above), theollowing numbers bear out as true (partial list):6

Number o participating companies, including sup-pliers and sub-subcontractors = 420

Number o participating individuals = 850Number o types o documents generated = 50Number o document pages generated = 56,000

Now, i 420 dierent companies are on the job, andeach one is primarily looking out only to protect their

own interests, wading through a small ocean o pa-per to make a prot, is it any wonder that eciencyis not at its peak?

This situation is not lost on owners, as observed by therepresentative o a large, global hospitality and lodgingorganization: The culture in the A/E/C industry hasor a long time been ragmented and inecient. Theindustry has lacked trust and been short on strategiccollaborative thinking.7

WaSte

Waste on a construction site comes in many guises:lost time, or instance, due to conficting schedules(subs getting in each others wayor behind schedule);wasted material (over-ordering to be sae); and lost op-portunities (items that could have been preabricatedor easy install now have to be tailored on-site).

In act, the Construction Industry Institute reports thatthe construction industry generates more than twicethe waste o the manuacturing industry.8

An accurate BIM can avoid lost time by catching anddisplaying scheduling conficts beore you even break

ground, making it possible to address and solve theseproblems beore any time is lost. As or material, dueto the more exact material estimate provided by BIM,contractors will order what they need or the job, notmore than that, and not less. Precision makes or avery lean process.

A correctly designed BIM, down to installation detailso HVAC systems and even wall systems, will allow

a much larger percentage o material to be preab-

ricated (pre-cut, pre-bent, etc.) o-site, where these



13/32

There were no

conflicts between

the systems that

were modeled and

coordinated using

BIM. Normally on

comparable

projects, an

estimated 100 to

200 conflicts must

be resolved in the

field using

traditional

methods.

processes can be perormed more economically, andwith greater precision. BIM allows or smoother and

aster installation, and with the certainty, through clashdetection, that there will be little or no confict.

This adds up to greatly reduced waste, which, o

course, drives straight to the bottom line.

CoStIn the traditional process, todays owner is smart i

he builds hety contingencies into his projects, as theabove ragmentation and resulting ineciencies otenlead to cost overruns that in turn also lead too oten

to value engineering (meaning, cut everything ex-

cept the absolute essentials needed to complete the

project within the available budget) or, at times, even

cancellation o the project.

A survey conducted by Construction Clients Forum

1997: FMI/CMAA 2005, 2006, showed that two-thirdso owners report cost overruns.9

The two main actors driving up cost are unreliable es-timates, which as a rule lead to expensive change or-ders in the eld, and delays in project completion thatexpensively postpone deployment o the project. Otheractors include redesign o conficting plans, rework oeld mistakes, and cost o litigation due, in essence, tonger-pointing.

APb S

The paradigm shit required or BIM and its process tosucceed is romfragmentation to teamwork.

A BIM project more oten than not involvesrom thevery beginning o the projectnot only the owner andthe architect, but also the consulting engineers, suchas structural and HVAC, the general contractor, as wellas subcontractors. All bring expertise to the table andare aorded input to the project, while such input stillmatters.

DPR Construction, a Caliornia-based, nationwide con-struction company, is aggressively pursuing BIM imple-

mentations with their projects and has already seen sig-nicant improvements in eciency, such as their recentCamino Medical Group project, a 250,000 square-ootmedical oce building.

As a direct result o BIM and the collaboration and co-ordination inherent in the process, DPR constructionachieved these impressive results:10

Labor productivity was 15 percent to 30 percent bet-ter than industry standards.

Less than 0.2 percent re-work was required on theHVAC system.

There were no change orders related to eld confictissues.

There were only two eld issues related to RFIs.

There were no conficts between the systems that weremodeled and coordinated using BIM. Normally on com-

parable projects, an estimated 100 to 200 conficts mustbe resolved in the eld using traditional methods.

And the key? According to DPRs Atul Khanzode andDean Reed: Collaborate, really collaborate. A strong col-laborative environment was cultivated on the CaminoMedical project. The spirit and enthusiasm to drive truechange, shared by all the major players, helped to over-come the lack o experience some parties had in using3-D modeling tools and Lean construction processes.Co-locating the design and detailing teams in the BigRoom, where detailers worked side by side to constructdesigns virtually and resolved conficts and issues im-

mediately, urther acilitated a highly integrated projectdelivery. The detailers used shared resources, includinga network server, printers and plotters. All constructiondocuments were generated rom this one room. Weeklymeetings were held to review progress and analyze andcorrect clashes using the 3-D model.11

green BuIldIngS

Another strong driver or BIM is the current prolierationo green building. Many see BIM and green building as amarriage made in heaven, and they are not so ar o.

energy analySeS

Given a detailed BIM design model, sotwares now ex-ist that analyze correctly not only the energy impact obuilding orientation (north-south versus east-west, or ex-ample), but also can calculate the benets or drawbackso various building orms, envelope material, windowtypes, light-xture arrangements and so on.

An analysis might nd that a tall, narrow building willoutperorm a shorter building with a larger ootprint,and that an exterior insulation and nish system en-velope will reduce energy consumption by 30 percentcompared to other claddings. This allows the owner to,

in eect, knowduring the design phasehow greenhis building will be once complete.

These analyses will also help the owner determine thelietime cost o operating the building, and will clearlyshow a return on investment and repayment periods,based on various designs and material.

CommunICatIon

As stated above, we see and think in three dimensions,and one o the great drivers o BIMespecially ater a



14/32

The communication

and understanding

facilitated by BIM

is possibly not

stressed enough in

the industry, but it

is one of the great

strengths of this

new technology

and process, and

may well become

its biggest driver.

team has gone through the entire process onceis theincreased understanding that three dimensions bringsto the table.

Visualizing the building in 3-D, and rom all conceivableangles, removes a good deal o uncertainty. It no longertakes an expert estimator with the knack o creating 3-Dbuildings in his head based on 2-D drawings, to ully

appreciate what hes looking at: The BIM is there, plainas day. Given that all data about the objects comprisingthe building are true, what you are looking at is a virtu-al representation o precisely what the team will build.

BIM, as a communication tool, lets the owner appreci-ate what his money will buy, lets the general contrac-tor see what he will build, and it lets the subcontractorunderstand exactly how and where he ts in, and veryoten, precisely when as well.

The communication and understanding acilitated byBIM is possibly not stressed enough in the industry, but it

is one o the great strengths o this new technology andprocess, and may well become its biggest driver.

ThePw f BIm

vIrtual BuIldIng

The key to grasping the inherent power o Building In-ormation Modeling is that during the design phase, thearchitect (and the owner), along with both engineers andcontractors, actually construct the building.

This bears repeating: They actually construct the build-ing.

With input and expertise rom all concerned, the projectis built rom the ground up in whatever detail is neededor the purpose o the model.

By collaborating at this phase, you can detect and re-solve conficts beore ground is broken, oras oneAWCI member so eloquently put itwhile you can stilluse an eraser.

What makes this possible?

Parametric Objects

A Building Inormation Model is constructed withPara-metric Objects, which are sotware counterparts o theactual thingsused to construct the physical building, suchas steel beams, concrete slabs and rebar, raming, dry-wall, ceiling grid and tile, ducts, windows and so on.

The parametric object is not only represented in threedimensions, but inherent in the object is all the inor-mation concerning it to make it intelligent. As an ex-

ample: A wall knows that it ends in an adjoining wall.Should the adjoining wall move 3 eet arther out, theinitial wall will then automatically adjust its length byadding 3 eet.

Technically, parametric objects, by denition:12

contain geometric inormation and associated data

and rules;have non-redundant geometry, which allows or no

inconsistencies;have parametric rules that automatically modiy as-

sociated geometries when inserted into a buildingmodel or when changes are made to associated ob-jects;

can be dened at dierent levels o aggregation;have the ability to link to or receive, broadcast, or

export sets o attributes such as structural materials,acoustic data, energy data, cost, etc., to other applica-tions and models.

Basically, parametric means that, depending on thedetail o the model, the object can be, and usually is,dened by more parameters than just width, depth andheight; it also can be dened by weight, density, relationto other parametric objects, cost, manuacturer, deliverytimeyou name it. You can basically tell all that youknow about a parametric object, which inormation thencomes into play when used in a model.

This way, when you are constructing the building vir-tually, you are building it with ully dened, intelligentobjects that know where they belong, how they relate

to other objects and what they consist o.

CoordInated deSIgn model

A strong point o BIM is that i you need to make a change,you only have to make it once, in one place.

In a traditional environment (2-D plans and drawings),the movement o a wallor a window or ductmaynecessitate multiple updates: rst in the main drawing,then o all detailed drawings aected by this change,which can sometimes run into dozens. This, o course,leads to the issues o making the change correctly in alldrawings, and then ensuring that all who need these

updates receive them.

The one change made in BIM will alter the location o

the wall, and will alsoand automaticallyadjust all

aected objects accordingly. The model is now currentand all you need to do is export or print 2-D plans

(as needed) rom the updated model and distribute

to those concerned.

This is urther acilitated by the act that, as a rule,

all members o the BIM team can access the BIM



15/32

A key strength of

2-D documentation

generated from a

BIM 3-D model is

that every team

member will

receive the same

version of the

plans, which,

provided clash

detection has been

run and all clashes

resolved, will give

an accurate and

conflict-free

design you can rely

on with confidence.

remotely, and so can print the detailed plans as

needed just beore beginning the work, knowing

now that they are dealing with current (and ully co-

ordinated) plans.

2-D DocumentationAlthough many designers now choose to model their

projects in virtual space rather than drating them in

the 2-D plane, the need or 2-D documentation is stillwith us and will remain or some time, primarily due

to regulatory and permitting agencies that will still,

and or the oreseeable uture, only deal in paper-

based (or CAD) 2-D plans and detail.

Also, many subcontractors are not yet equipped to

work directly with 3-D models and will need 2-D

plans or their portion o the work.

The good BIM-news is that every BIM tool vendor on

the market oers the acility to generate 2-D draw-

ings o any area o the model, in whatever detail is

required (to the extent supplied in the BIM).

Version ControlA key strength o 2-D documentation generated roma BIM 3-D model is that every team member will re-

ceive the same version of the plans, which, provided

clash detection has been run and all clashes resolved,will give an accurate and confict-ree design you can

rely on with condence.

How oten have you built according to your set o

planswhich clearly show that you have the right o

way and show absolutely no intruding electrical orHVAC itemsonly to discover that the HVAC plans,

whether an earlier or later version than yours, install

16-inch ductwork precisely where you had planned

to hang the ceiling grid?

BIM can put those days behind us.

PrefabricationWhen it comes to cutting construction costs, ew

things, i any, come close to preabrication.

For one, an o-site acility is builtor manuacturing,

whereas the on-site manuacturing area, by the na-ture o the beast, is always improvised to a greater or

lesser degree. Also, o-site manuacturing is always

more economical and will yield a higher-quality prod-uct due to closer actory control.

Further, installation o a preabricated item, made

to specs or a given place, will go much aster than

building it on site. This will not only cut down the

subcontractors time spent but also will speed up

the entire project.

Also, items abricated o-site take up no on-site

space during manuacture, and so will not obstruct

contractors.

Preabrication, o course, is nothing new; structural

steel, precast concrete, exterior panels and curtain

walls are oten preabricated and shipped install

ready to the job site.

It seems that BIM was designed with preabrication

in mind. Whereas prior to BIM, the designeror

more commonly the contractor or subcontractor

would develop detailed 2-D documentation or the

o-site manuacturer, who in turn would convert

these drawings to CNC (Computer Numerical Control)instructions or the automated machine production

o the items in questionsuch as the dimensions o

a steel girder.

I this same girder were designed in BIM in sucient

detailwhich normally is the casethe BIM program,

instead o generating the 2-D detailed drawing, caninstead automatically generate CNC code and trans-

mit this to the relevant preabricator. Or better still, i

the preabricator already deploys 3-D manuacturing

technology, the BIM can utilize Direct Data Exchange(DDE) and send the manuacturer or preabricator therelevant portion o the BIM, or production.

Preabrication has already made great inroads with

HVAC systems. On the DPR Camino Medical Oce

Building Project, the HVAC contractor saved 33 per-

cent o eld labor hours by creating parametric and

ully coordinated 3-D models and using them to pre-abricate the medium- and low-pressure ducts.

And so a maxim is emerging: The more the building

can be built off site and then assembled on-site, the

better the savings, both in labor and in material costs.

Analysis ToolsWhile BIM tools allow you to create a 3-D model downto abrication-level detail i you so wish, they gener-

ally do not come out o the box with analysis tools

to simulate and analyze the buildings perormance

in various categories and under various conditions.

To meet this need, a host o third- party vendors hascreated analysis tools that interace with and import

BIM data rom main modeling tools, which will then

run requested simulations and analyses based on

the imported data.

Tools exist or areas such as these:

Clash Detection Analysis

Energy (Perormance) Analysis

Structural Analysis



16/32

The BIM 3-D model

itself will give the

experienced

contractor most of

the certainty he

needs.

Additionally, once

the model is

created in requisite

detail, including

sequencing for

various zones of

the project,

analyses can be

run against the

model to validate

feasibility and to

highlight areas of

potential problems.

Estimating/Cost Analysis

Acoustic Analysis

Lighting Analysis

Building Form Analysis

Water Harvesting Analysis

Renewable Energy Analysis

The common strength o these tools is the ability to

run what i scenarios to determine the optimumcourse o action. What i we used 50 percent ewer

windows on the eastern ace o the building? How

would that impact energy use or lighting needs? The

BIM designer would reduce the window-count by

hal and then run the test analysis again. This way

the most ecient building, or the building that most

closely meets the owners needs, can be designed

with the certainty that it will perorm just so in the

real world as well.

Clash Detection

The analysis that may eventually put aspirin and TUMS

out o business is the Clash Detection Analysis.

A hard clash is where objects in the design occupy

(or try to) the very same space; a sot clash is where

objects in the design are placed so close to each otherthat there is no room or construction or access, or

so close that building codes are violated.

Traditionally, in the 2-D drawing environment, clashesare detected by the manual process o overlaying in-

dividual system drawings on a light table, and visuallyeyeing the clashes. In a CAD environment, the same

principle applies, whereby the designer can synchro-nize and overlay several CAD drawings and, again

visually, identiy potential or actual conficts.

In the not very common BIM scenario where all par-

ticipating team members are using the same sotwareplatorm and, in eect, working on one single large

BIM 3-D model covering all disciplines, the clash will

not be permitted by the BIM tool itsel, which will raiseappropriate fags i an objects space is encroached

upon by another.

The norm, however, is that dierent disciplines o

the design and construction team will do their workon dierent sotware platorms. The structural teammay be using Tekla, the architectural model may be

built using Revit, the electrical contractor may use

Bentley, and the HVAC engineers may deploy Gra-

phisot. These applications do not speak directly

to each other and so cannot alert one another that

clashes occur.

In this scenario, there are sotware solutions like Navis-Works that can import the 3-D models rom diverse

platorms and combine them into a single model, pri-marily or the very purpose o clash detection.

Once the structural, architectural, electrical and HVACmodels are combined into one, NavisWorks will high-light hard and sot clashes or team resolution, which

means the HVAC engineer may go back and do somere-routing, and then reload the corrected model or

another clash detection run.

You repeat this process until NavisWorks gives the

green light: no conficts or clashes, which means that

i this version o the designs is the one to be built,

there will be no costly and time-consuming conficts

to resolve in the eld at time o construction.

It is not surprising that Clash Detection Analysis is

one o the most popular BIM applications today, and

the one that quickly tends to have a high rate return

or the users investment.

ConstructabilityCan you build this thing? That is something the generalcontractor needs to determine with some certainty.

The BIM 3-D model itsel will give the experienced

contractor most o the certainty he needs. Additionally,once the model is created in requisite detail, includingsequencing or various zones o the project, analyses

can be run against the model to validate easibility

and to highlight areas o potential problems.

Structural

Structural engineers need to veriy that the columns,beams, slabs, etc., o the building will hold up under

expected loads. Most architectural BIM tools do not

represent such structural elements in sucient detailtoday to aord an actual structural analysis.

To solve this issue sotware vendors have created

modeling tools that provide the structural objects andrelationships (connections and connection releases,

etc.) called or by the engineers in order to analyze

the structure properly under various loads.

These products maybe reestanding applications

that mirror, but are not incorporated into, the coreBIM sotware.

Performance

An owner may need to determine, beore breakingground, exactly how his project will perorm. He may,or example, need to know the energy consump-

tion o the building, whichespecially over the lie

o the building translates into cost; or he needs

to determine the acoustic or lighting perormance

o the building in pursuit o a LEED (Leadership in



17/32

Once the model is

complete, or even

during early stages

of design, you can

link the BIM 3-D

model to energy

analysis tools to

determine energy

use in its current

iteration

Energy and Environmental Design) Green Building

certication.

Energy

Once the model is complete, or even during early

stages o design, you can link the BIM 3-D model to

energy analysis tools to determine energy use in its

current iteration.

As the model develops into urther detail, several

what-i scenarios can be created or the model such

as re-orienting the building ve degrees in either di-

rection and then re-running the analysis to compare

the results.

Other what i scenarios may include varying the

size o HVAC systems and anticipated heat genera-

tion within the building (type o lighting, occupancy

rate per room, etc.).

Since energy costs, measured per square oot, con-

tribute to the annual operational cost, investment inenergy-saving eatures such as a using material with

a higher R-value may return their investment in ve

or six years. I the owner plans to retain and operate

the building upon completion, he may very well opt

or better insulation or operable windows. The avail-

able analyses make deciding the best path to ollow

easy and unequivocal.

Speculative projects built or immediate turnover

upon completion rarely ocus on energy issues to thisdegree, unless LEED certication is being pursued as

part o a building marketing strategy.

Acoustical

Analysis packages can run reverberation time acous-

tical analyses or various scenarios, allowing the

designer to test or and decide on the appropriately

STC (Sound Transmission Class) rated building ma-

terial, especially in areas where noise pollution may

be an issue, or, again, where LEED certication may

be sought.

Lighting

Similarly, an analysis package can simulate the light-

ing levels or a building as designed, taking into ac-count the number o windows or refective suraces

within the building.

When the designer analyzes lighting, he or she is

mostly interested in daylight and in determining howmuch o it enters the building, and how deep into the

building it will provide workable light-levels or em-

ployees. Ecient and comortable lighting is a LEEDcertication criterion as well, and is mostly addressedwhen the owners are green-aware. O course, high-

eciency xtures, although more expensive, draw

less energy or the same illumination, and may also

be evaluated by applications.

Estimating

While you can view estimating as just another analy-

sis tool, this is a subject near and dear to all contrac-

tors and subcontractors, and BIM brings good news

to this eld.

An accurately built modelmade in sucient detail

to incorporate individual, suppliable objectscan, aspart o the parametric data or each object, include

a link to a costing databasewhether to a local le,

updated as needed or to a suppliers database or up-

to-date pricing at any time.

Given a complete model, it knows exactly how

many o which items it consists o, and the take-o

becomes nothing more than selecting the right menuitem and clicking the mouse.

A quantity take-o generated by a computer rom a

construction model is much more reliable that one

generated by traditional methods, which rely on the

estimator marking the paper drawing with a elt pen

(to indicate items already taken o) or, i using CAD,

with textures to show the item has been counted.

When one makes mistakes in traditional quantity

take-os, they are usually in this area: one misses

something, or something is taken o twice. The com-puter, on the other hand, using the 3-D model, does

not make such counting errors.

I viewed only as an estimating tool, which is aster:

taking-o traditionally rom a 2-D drawing, or build-

ing a BIM 3-D model rom which to run a takeo?

Most likely the ormer, but dont orget that estimat-

ing is only one o the models many uses; it is now

available or all other benets as well.

Automatic quantity takeo based on the 3-D model

does, naturally, not replace estimating as such. What

you get rom the model is the complete shopping list inaccurate quantities and with accurate pricing (though,

keep in mind the garbage-in/garbage-out principle).With this in hand, you will still need an experienced

estimator to view the 3-D model in some detail

specically in areas o staging, possible congestion

on the site, need or scaolding or other material

that may or may not be modeled in the BIM tool,

etc.who then, based on his own understanding o

the project and knowledge about costs, can make a

realistic, accurate estimate.



18/32

As BIM gains

industry-wide

traction, more and

more

manufacturers will

no doubt BIM-

enable their

catalogues to

interface with all

major BIM tools.

Building Element Models (BEM)To help speed design, many BIM design tools providepre-dened libraries o both xed geometry and para-metric objects. These are typically generic as to size

and unction and based on customary construction

practices. Objects rom such libraries serve their mostuseul unction early in design when the nal param-

eters may not yet be knownto then be rened as

the design progresses.

As nal dimensions and other parameters become

known, the designer can either copy and modiy a

library object, or design one rom scratch.

Building Element Models are BIM representations o

physical products such as doors, windows, xtures

and high-level assemblies o walls, roos, ceilings andfoors consisting o a combination o parametric ob-

jects and the detail needed or the current project.

Some design tools may include BEMs as part o their

libraries.

More importantly, however, manuactures o buildingmaterials have begun to recognize the importance

o BIM, and some are now listing their product inor-

mation in an optional BEM ormat, providing ully

parametric objects with geometric connectivity or

sotwares such as Revit, ADT and to some degree

Bentley and ArchiCAD.

As BIM gains industry-wide traction, more and more

manuacturers will no doubt BIM-enable their cata-

logues to interace with all major BIM tools. Down

the road, when an open interace standardmostlikely IFC (Industry Foundation Classes see discus-

sion under Interoperability below) has been agreed

to and endorsed by all BIM players, all construction

supply manuacturers will most likely display their

wares in such ormat.

The biiSmart ic

The buildingSMART alliance was created to spearheadtechnical, political and nancial support or advanceddigital technology in the real property industryrom

concept, design and construction through operationsand management.

The buildingSMART alliance operates within the in-

dependent nonprot National Institute o Building

Sciences. This public/private initiative expands on

goals o the North American Chapter o the Interna-

tional Alliance or Interoperability, whose Industry

Foundation Classes have initiated open standards

or national and international links among industry

players. It provides developers and users o building

inormation models the digital tools that are increas-

ingly helping to share highly accurate inormation

throughout a acilitys lie cycle.

In contrast with centuries-old ways o documenting

acilities with two-dimensional drawings plus speci-

cationsa process recently automated with ComputerAided Design (CAD)new digital technology brings

together owners, operators, designers, constructors,regulators and other stakeholders around a single BIM,a unied tool that oers unprecedented accuracy,

speed and economy. The closely related concept o

open standards that let all users communicate quicklyand eciently, nationally and internationally, led to

the creation o the International Alliance or Interop-

erability and the coinage buildingSMART.13

This is the organization that will make interoperabilitypossible. The proposed open standard is called IFC.

InduStry FoundatIon ClaSSeS (IFC)

The Industry Foundation Classes were developed tocreate a large set o consistent data representations

o building inormation or exchange between AEC

sotware applications, such as BIM modeling tools,14

and were designed to address all building inorma-

tion, over the whole building liecycle, rom easibilityand planning, through design (including analysis andsimulation), construction, to occupancy and opera-

tion (Khemlani 2004).15

Industry Foundation Classes, as an eort to accom-

plish open data-exchange between BIM platorms, is

run and coordinated by the buildingSMART alliance,whose vision is the sharing o inormation between

project team members and across the sotware appli-cations that they commonly use or design, construc-tion, procurement, maintenance and operations.

The buildingSMART alliance sees data interoperabil-

ity as a key enabler to achieving the goal o true BIM

eciency, and is thereore working on developing a

common data schema that makes it possible to hold

and exchange relevant data between dierent sot-

ware applications. This data schema comprises inter-disciplinary building inormation as used throughout

its liecycle.

The name o this ormat is Industry Foundation Class-es; it is registered by International Organization or

Standardization as ISO/PAS 16739 and is currently

in the process o becoming an ocial International

Standard ISO/IS 16739.

Sotware applications store the building inormation

in a native and proprietary ormat. In order to make

this valuable inormation available to other project



19/32

Spending as much

timewithin

reason, of course

as the architect

needs and wants,

BIM will enable him

or her to play

around with

various designs,

approaches or

materials, and

actually see (and

allowing the owner

to see) not only

what the design

will look like, but

also how it will

perform as a

building.

participants, their sotware applications either all

have to understand the native ormats o the other

applications, or preerably, they support IFC as the

open ormat or building inormation models. Indus-

try Foundation Classes can be used to exchange and

share BIM data between applications developed by

dierent sotware vendors without the necessity to

support numerous native ormats. As it is an open

ormat, it does not belong to a single sotware vendorand is thereore neutral and independent o a par-

ticular vendors schedule and development direction.One could say that Industry Foundation Classes is

open BIM as opposed to proprietary BIM.

Sotware applications correctly implementing IFC

are said to be IFC compliant, as they allow one to

read and/or write *.ic les. It is important to under-

stand that every implementation o an IFC exchange

should ollow a so-called Exchange Requirement. An

Exchange Requirement documents which inorma-

tion needs to be present in an exchange/sharing o

data at a certain stage in a project. It is not specicenough to ask or an IFC le, which basically can be

compared to asking or an Excel spreadsheet with-

out speciying which data you expect to be present

in that spreadsheet.

Exchange Requirements are grouped into somethingcalled an IFC View, i.e., a particular subset o IFC

dedicated to a set exchange purpose. Most currently

available IFC compliant sotware has implemented

the IFC coordination view, but there are other IFC

view denitions, e.g. the IFC structural analysis view.

Within each o these views, there can be several ex-change requirements (i.e., or dierent domains in

coordination view etc.)16

Architects eis

Designers and their allied engineers are right behind

the owners in seeing the advantages and benets

o BIM.

Not only will BIM allow the designers to try, and test,

various conceptual design approaches, but once the

concept has been settled onand bought into by theownerthe architect can now construct the building

virtually, and in such detail as needed to answer theiror the owners questions in areas o:

Optimum building orientation

Optimum building material

Energy eciency

Green requirements

Construction cost

Construction schedule

Operating costs

By providing clear insight into these issues, beore

ground is broken, BIM aords the design team a high

degree o certainty and o know beore you go. Andwhen you minimize later conficts, you also minimizeerrors and omissions, and the risk o liability.

deSIgn ProCeSSArchitects are artists at heart.

And as artists, they like to conceptualize. They like

to assess dierent aesthetic approaches; or they like

to design something with unorthodox materials, per-

haps even based on untried-as-yet shapes or layouts

(think Sydney Opera House or the Walt Disney Con-

cert Hall in Los Angeles).

The 2-D drawing world does not lend itsel to con-

ceptualizing; it soon grows too costly, especially i thedesign is out o the ordinary, or how best do you com-

municate it to the potential owners? Oten, in orderto get the design across, the architect will then resort

to actual three-dimensional mock-ups o the projectexpensive at best, cost-prohibitive at worst.

And how many concepts would the architect like to

try? How many 3-D mock-ups can the rm, or the

owner, aord?

At the conceptual stage, the architect should have thereest reins possible, those with the ewest cost- and

time-constraints. And this is what the BIM not only

promises but delivers to the designer.

Spending as much timewithin reason, o course

as the architect needs and wants, BIM will enable

him or her to play around with various designs, ap-

proaches or materials, and actually see (and allowingthe owner to see) not only what the design will look

like, but also how it will perorm as a building.

Basically, at this stage, BIM gives the architect much

sought ater (and dreamed o) reedom to create.

Team Design

Once the building concept has been agreed upon bydesigner and owner, the wise architect now invites

as many o the players as he or she can contractu-

ally involve; at minimum the consulting engineers,

the general contractor, specialty contractors (HVAC,

plumbing) and as many other subcontractors as

possible.

With the conceptual questions settled, this team will

then knuckle down to build the actualbuildable

structure in virtual 3-D space.



20/32

BIM affords you

the opportunity

not only to ask

What if we did so

and so?, but also

the power to

answer such

questions.

Make no mistake, the architect does take the lead in

this, but he or she will work very closely with the en-

gineers (civil, structural, etc.) who will not only have

input to give in the overall design but will also extract

applicable portions o the design (such as structure)

or detailed analyses in their own systems.

The architect, at the team design phase, is also wise

to welcome points and suggestions provided by boththe general contractor (who knows what it takes to

build the thing) and the subcontractors present, who

will also speak rom a very practical angle when they

suggest that what the architect just proposed might

in act not work or will generate conficts arther

down the line.

Big RoomThe process should take place in an i-Room (inorma-tion room) orBig Room (another word or the same

thing)a room large enough to house the entire teamand all the necessary computers and display screens

or everyone to ollow the process in detail.

This is stressed repeatedly in BIM reviews and litera-

ture: Get the team together in one spot. The design

is, in essence, a collaborative team design under the

conductorship o the architect.

What IfsAnalysesIn team mode, or perhaps in separate sessions, you

can pose many what-is.

In the traditional 2-D environment, what-is usually

lead to conjecture rather than answers, and conjecturemay be a very fimsy oundation upon which to erecta twelve-story hospital. BIM aords you the opportu-

nity not only to ask What i we did so and so?, but

also the power to answer such questions.

Usually, what i questions centers on eciency.

Would cooling costs be reduced if we used operable

windows? Or By how much would ICF reduce the heat-

ing bill?; and What would be the payback period of us-

ing ICF rather than traditional cladding? Here is where

BIM excels.

Given a design, the architect can runor have anenergy consultant runan initial energy analysis as

a benchmark. The architect can then substitute the

conventional cladding with ICF (and its higher R-value)and then re-run the energy analysis. Based on the

result, he or she can then calculate HVAC cost sav-

ings (both by needing a lesser capacity system and

in lowered electrical costs) and so determine the ROI

o the added ICF cost.

By similar what is and analyses, the design team

can also calculate various environmental impacts o

design choices, and so arrive at the optimum building,one that meets the owners needs in the most energy-ecient and environment-riendly way possible.

Level of DetailA reminder here about garbage in/garbage out, or, in

this case, accurate level o detail.

To simulate and analyze the impact o, say, masonry

versus EIFS, the BIM 3-D model has to know the R-valueand other relevant properties o each. It is thereore

incumbent upon the designer to create the model in

sucient detail to acilitate such analyses.

The only way to determine the level o detail needed

in a model is to speciy its use. For what purpose are

you creating the model?

I it is purely conceptual/aesthetic, the model needs

to know nothing o R-values or acoustics, but it must

show the physical components o the building in3-D and visually (and more or communication pur-

poses than anything else). But there ends the need

or detail.

At the other end o the scale o detaili the BIM

3-D model will be used or application-to-application

transmission o manuacturing-specic data (as or

preabrication)the data in the model have to be

very precise and in such detail that the machinery

that will manuacture the items can act on the inor-

mation received rom the BIM 3-D model and build it

with precision (this is known as DDE, or Direct DigitalExchange o CNC, or Computer Numerical Control,and requires BIM data at least as precise as a high

quality shop drawing).

GeneralCcs

Entering the nuts and bolts world, the general con-

tractor is, as a rule, third man in.

And this is where the RFIs and change orders normallyoccur. With BIM, you can avoid those problems up

ront, while an eraser can still be o use. For it is thecontractor who, with a critical and experienced eye,

looks at the model and points and says, There, right

there. Wont work. Youll have a crane there while pour-ing the slab. And the designer will look at him, and

the engineers will look at him and then at the model

and suddenly nod, and any subcontractor present

will nod, too, and then the designer, nally, as well;

and so, then and there, they can arrive at a working

alternative and incorporate that into the design.



21/32

Although the

subcontractor, by

contractual

necessity, is

usually the last

man to the BIM

table, and

sometimes doesnt

even make it there,

BIM provides him

or her many, and

quite specific,

advantages.

Subcontractors

Although the subcontractor, by contractual necessity,is usually the last man to the BIM table, and some-

times doesnt even make it there, BIM provides him

or her many, and quite specic, advantages.

PreFaBrICatIon

Subcontractors such as HVAC and plumbingwhichas a rule have o-site shops o varying degrees o

sophisticationquickly see the benet o BIM and theshop drawing/preabrication detail model, which in

essence can communicate via DDE and deliver CNC

data to the shop manuacturing machines, which

in turn can produce the assemblies necessary or

the job.

More and more design teams now include HVAC and

plumbing contractors or that very reason.

ClaSh deteCtIon

Another actor that has called HVAC and plumbingto the BIM table is that they are the trades that mostcommonly clash in the eld, both ghting or scarceand prime real estate between slab and suspended

ceilingthe HVAC intake duct insisting on occupy-

ing the same space as the plumbers major waste

lineand so easily see the great benet o the clash

detection, and resolution, provided by BIM.

It is also important to remember that it is only with

the condence that there will be no clashes on site,

once assembly begins, that the HVAC and plumbing

contractor can preabricate many o his assemblieso site.

Ideally, the main design model will also include all

HVAC and plumbing details, but what normally hap-

pens is that the HVAC and plumbing contractors

design their systems using their own sotware, and

then eed the results to a surace modeler such as

NavisWorks, which is well set up to run clash detec-

tion analyses.

take-oFF and eStImatIngSame as or the general contractor, the subcontractor

will benet greatly rom accurate take-o quantitiesand a good construction-sequencing view to deter-

mine how crowded the site will be when they arrive.

Armed with this inormation, the experienced estima-tor will, and does, work up an accurate quote with-

out having to look around corners and second-guess

the architect as to what he or she really intended.

Wall Cii Ccs

So ar, the wall and ceiling contractor has not been

a requent guest at the BIM table. This is not to say

that he should not be there.

For one, any work done or the Government Services

Administration will require a BIM 3-D model or their

space and acility management, and so is a requisiteor any contractor bidding GSA work.

For another, although the benets may not be as ap-

parent as with HVAC and plumbing (Clash Detection

and Preabrication), there are still benets to be de-

rived rom early wall and ceiling contractor involve-

ment in the process, and their deployment o BIM

technology.

take-oFF and eStImatIngAs with other subcontractors, an accurately detailed

BIM 3-D model will give you not only the location andinterrelation o each wall-and-ceiling item, but alsothe recipe o what exactly comprises each compo-

nent or an accurate take-o quantity.

Given this a clear view o the construction sequenc-

ing, the BIM 3-D model will then aord the estimator

a rm basis or a good bid.

Pat Arrington o Commercial Enterprises, Inc. in NewMexico is investigating BIM primarily rom that angle:Using BIM, i the process is ollowed, there is going

to be very little chance o not having the right com-

ponents covered in your estimates.

I think that the virtual graphics o BIM will allow per-

haps even a neophyte, or at least a less experienced

person, to understand the complexity o a job and

to put all requisite components together.

Years back, we were only covering up raming. To-

day we have rewalls, sound walls, smoke walls and

positive-pressure walls to seal and keep out contami-

nants rom another sourceeven negative pressure

walls, things we did not have beore. Our trade has

become a lot more complicated. I you throw LEED

and green building into the mix as well, you will al-most need BIM to visualize the project and make sureall the pieces are included.

As an aside Arrington adds, We also have millions

o dollars in negotiated work with the GSA, which

requires BIM as part o the contract to aid acility

management. I believe that the big school districts

are now also beginning to ask or BIM or the same

reason.



22/32

Thats where I see

us benefiting from

BIM: We will be

able to trust the

design to the point

where we no

longer have to

include the

re-work margin in

our bids.

ClaSh deteCtIonBIMs ability to detect hard clashes (two objects oc-

www.awci.org pdf bim

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