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#7. I rest my case! 200 models?
Posted by Don Henrich on Thu, Apr 30, 2009 @ 05:19 PM
The GSA has had over 100 BIM models on a single project according to ENR -- and the count may reach 220! I have been in more than 100 meetings over the past 4 years where people at the conference room table just wanted there to be 1 model that did everything and wanted me to say so. But true to my beliefs, there is a need for more than 1 model. There is also a need for a Services team to assist the customer in achieving his or her Construction Management goals, particularly when firms are tooling up their BIM skills and/or when an Owner mandates a project must be done in BIM.
The snippet below is excerpted from Nadine Post's 4-29-09 ENR article, "Digging into 3D Modeling Unearths Many Worms." The article illustrates that user experience is exactly as I have been portraying it for 5 years. It's good to hear someone else say it!
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BIM veterans also agree that modeling changes the design and construction process. The idea is simple: eliminate redrawing the drawings by putting information in once and using it over and over again; catch conflicts before construction begins rather than in the field, when construction dollars are being spent; and use VDC for estimating, scheduling and fabrication. The execution is difficult. BIM veterans caution rookies to hang on tight and expect the unexpected.
The redesign of the design process needs to take into account the order of construction and model content. It's important to resist the urge to model until protocols are worked out and the program is set.
Sources have learned the hard way that there are no minor design changes, especially if models have already been coordinated. For example, if an engineer moves a beam it can affect other systems, and their models, down the food chain. Models then have to be reviewed, adjusted, checked and re-coordinated.
In the best of all worlds, the contractor and prime trade contractors should be in the room during design process redesign and at times, during design. Input on cost, constructibility and schedule can save model rework and field problems.
Design-construction collaboration is not as easy in a traditional design-bid-build environment as it is with integrated project delivery, design-build and construction management at-risk. For an IPD hospital project for Sutter Health, 30 leaders of the building team spent nearly six months redesigning the design process, moving sticky notes around on a wall (see p. 28).
BIM means more time is spent on design. This can be irksome to designers if they are not compensated. Many maintain they are doing the contractors' work, without reward. Designers also find that to produce 2D drawings from BIMs they must revamp traditional in-house workflows to align with 3D model conventions.
BIM rookies should get help, define a process and expect the unexpected.
At BIM's conception, many expected there would be one BIM per building. The lesson learned is most BIM-enabled projects have myriad models. Many times the design model cannot be used by the trade contractor directly, thanks to software incompatibility or set-up, or both. Most often designers won't give their models to the contractor for fear of liability if there is a computer glitch or a dimensional inaccuracy. Those that do share usually issue a disclaimer, "Use this at your own risk, for reference only." That means the contractor has to check every detail of a design BIM. Often, the trade contractor's detailer finds it easier to create a model from 2D drawings produced from the design model.
On the courthouse project, there are more than 19 design BIMs and more than 60 construction BIMs. On the hospital, so far there are 125 models. That number is expected to grow to 220.
So much for the idea of one model per project. So much for the idea of entering information once and using it over and over again. So much for reducing the likelihood of human error while remodeling.
Sources advise that if BIM is a mandate from above, be sure to nail down owner's expectations for each building team member-especially if they are not outlined in a contract. Speak up if the expectations seem unreasonable or unreachable. Owners can be naive about BIM's capabilities.
COMMENTS
This is a great step forward. Many times we have argued of the benefit 'knowledge transfer' on top of direct data transfer. The necessity of multiple models not only goes to the intent of the modeler/designer, but also to the various objectives every model looks to achieve, which inevitably creates the need for different models, different software, different skill sets. Too many have found a marketable benefit in the promise of an all-encompassing model, but overlook the benefit of the knowledge gained, and the checks and balances set up by a multiple model system. It's great that a respected leader like the GSA is speaking to this. Thanks for the post.
Don: I see where a lot of people are selling their services as "BIM Experts". I have had to do several commercial projects before I understood my own BIM workflow; and I have been an architect for 32 years. Just running a BIM authoring software such as Revit, etc. does not a BIM expert make. I now have separate BIM models for my steel stairs, and frame. I have also found that changes are easy for me, but with the combination of my subs; things can get complicated (mystakes are overlooked). I have also found that getting a BIM project to work takes more more effort than just making a model -- slight changes are easily overlooked, and can multiply throughout a project with out being recognized.
Ed, I know exactly what you mean. As a Facility Owner, we consume a lot of design and design management services. Almost every contractor/consultant that comes through (even if they can barely open their email or run a ppt slideshow) claims to be able to 'do BIM' or 'handle BIM' or 'oversee the BIM for the entire system' or bill themselves out as 'expert CAD or BIM Management'. I don't buy it from 99% of them. I've talked to very few BIM "Experts" in this city and they've been on the scene for a long while, learning and teaching and broadening their skills slowly. So, while folks may be trying to sell themselves and capitalize on our momentum (can't blame them), the moment I'm brought into the room and hear them go on like that and follow up with an apocryphal statement about BIM... I just write them off because they can't be taken seriously. Obviously, we're all going to be learning something new with every project, but, I want to hire folks who know more than me (not someone who has only been a 'consultant' for the three months since their local reseller training. ;) ). This article had a great topic!
How important is it for the Architect to design in a building information modeling environment? Does it make any sense to start the modeling process once the design is done, by the draftsmen or cad tech's? Isn't this a major shift in workflow?
I can understand 19 design models - one from each trade involved in design. I can understand sub-models, or context models nested or joined in a master. But that does not seem to be what Don Henrich is talking about here. I can imagine a campus project with 10 site models: survey, grading, several utilities, landscape, etc. and 10 buildings with 15 models each making a total of ~160 design models. That does not seem to be the explanation either. I could also (maybe) understand counting analysis models such as structural, energy, furnishings, equipment, daylighting, artificial illumination, and rendering (one or more for interiors, another for exteriors), and for construction, such as material takeoff, pricing, and scheduling. Some of these are performed by non-modeling software on existing models. They produce reports of one kind or another and produce files which can be edited and saved. Those are models, albeit considerably more abstract than a BIM is, and they are not BIMs themselves. The rest can be modeled as BIMs, and there is no real reason they could not be modeled within an existing BIM, except that a different consultant or designer might be developing the information. But let's be inclusive, and add another 20, making a total of 50 "Design models" including a few that could be called "construction" models. Iterations (What if's), are not being counted. I can understand 60 more models on a complex project if models are among the submittals required for most systems. So, there is 100, but that includes what I believe Mr. Henrich is calling construction models. I suppose that spreadsheets and each specification division could each be seen as a model since they are digital abstractions of all or part of it. But in this context, I don't think they count. Iterations and combinations of models would push well past 220 in number. If I read Vico's literature right, I don't need to merge model files in order to use them together. (This sounds like a real good thing to me, by the way). So, I would not count those in the number required or used for the project unless I was out to establish a record for the number of models used. I don't think these are being counted in Mr. Henrich's article either. So where are all these models coming from? My real point is that the number of models is fairly meaningless without knowing what they are and how they are being used. "Big" BIM can anticipate many more models, it is true. So far (in 10 years) I have not had to manipulate more than 10 models for a single project, and most of them came to me as 2D dwg's. Most of them are never updated, and only a handful have been updated more than once, one 7 times. It could be argued that BIM is not really happening until at least two BIMs can be used in concert. But as a journey starts with a single step, nobody's first BIM project should anticipate the use of more than one model. When it is time to try "Big" BIM, try to find a project where a few models can be expected. If someone is trying to manage 100 active models (let alone 200), I hope they have a staff of 10 BIM whizzes.
This may not be the best place to post what follows. Feel free to take it down, as is your perfect right. It won't even hurt my feelings. I speak as a 12-year vet of ArchiCAD - a medium sized architectural fish (office) in a smallish construction pond (market). Change the workflow? More time spent on design? You Betcha. It makes sense that constructing a building virtually (even without the nails in the drywall and washers in the steel connections) and imbuing each element in it with the properties traditionally carried by technical specifications would take longer than it would to draw and specify the same building as 2D abstractions and text. A big hunk of the shop drawing process gets moved into the design phase, before the contracts that traditionally cover the cost of developing that level of detail are even written. It gets to be more than irksome. It becomes a question of viability. In a design-bid-build, or even a negotiated GC with subcontracts bid, the documents are essentially complete before half the team is even selected. At that point, nobody wants to wait even one week (let alone six months) while we all settle on a process and harmonize everyone's models. So what to do? 1. Get my client (owner or preselected GC) "on-board" with BIM at the outset. Write the cost into the design fee? This modeler (an architect) finds that the Owner does not care about having a model. They want the doors the right size, in the right place, a low fee, a low construction price, and a building permit. Life cycle cost is not even usually an issue. If it were not for the financing available and the tax implications, the project would be expensed instead of depreciated. The structures are off-loaded as needs change. They would really just as soon lease as build. Three-year payback is how the time horizon is defined for these projects. There are exceptions; once every few years we have a client with a 10-15 year time horizon for the project. General Contractors (whether bidding or negotiating for the job) do not want a model, they want a low fee (lest it nibble at the construction budget), legible, non-conflicting documents, few changes unless they are suggesting them, and (if they want any CA services at all) fast response to inquiries and submittals. So I need to sell BIM to a client with a promise that it will save money "in the long run" when I have very little control over the assumptions inherent in the quotes which will come from the trades, and no-one knows how long the "long run" is. Of course, I cannot make that promise. Without the whole team at the table, I am left with very watery arguments in favor of BIM. 2. Finance the extra time cost myself and recover it from subcontractors and fabricators who want the model to expedite prep of their shop drawings? A subcontractor or fabricator three contracts away from the designer, and months away from the design phase may want a model to expedite prep of shop drawings or fabrication, but that subcontract cannot bear the cost of my time (or training) to detail my model as needed for the purposes of every trade who might want, or be able to use that level of detail. My projects are typically $1M -$5M. Not many of the Generals, subs, and supply bidders are sufficiently BIM-savvy to capitalize on the existence of even the most detailed BIM. So, I am unlikely to be able to recover any costs that are not of value to my own operation. I am open to other ideas of how to handle this situation. I am stuck on a cusp. Right now, I stretch the design budget by using the surplus I can derive from faster documentation I can do with BIM. With the squeezings, I try to cover the cost of - doing the enough modeling to derive the CD documentation accuracy and coordination benefits of BIM - doing enough modeling to support my own internal coordination (using visual (not automated) clash detection and constructability analysis, mostly) - wrestling with the display parameters of pre-packaged model objects - training my crew in how to do BIM somewhat efficiently - devising workarounds when the software just won't yield acceptable hardcopy output without some help. - Oh, yes ... and my own re-education. I have not found a way to move past this point without some support from clients or contractors. They don't see the value yet. If I were them, neither would I, so it is a tough sell.
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