GSA, Disney Studios
I am watching the development of BIM (mostly as a buzzword, not as a tool), and I just shake my head. The BIM (Building Information Model) is, in my mind, a work product that some day will be composed of an assembly of solid model objects that not only have geometric attributes (how big, where, etc.), but also physical attributes (mass, color, thermal condutivity, flammability, light transmittance/reflectance. etc.). Such an assembly is capable of interference checking, aggregated thermal performance, fire spread modeling, traffic flow analysis, deflection, and so on, because it will peform appropriately in a simulation with the appropriate data and visual output. The ideal situation is that the general model can be queried in such a way so that various graphic, verbal, or economic “views” (plan, detail, specification section, schedule of values, etc.) of the virtual building can be generated from the same database in the same way that the General Ledger in an accounting package can be used to generate both P&L Statements and Balance Sheets. Such modeling has been the holy grail of CAD every since I have been involved in CAD (going back to the early '80s).
There are a couple of problems…
The historic problem has been raw computing power. That is why we have tended to break the modeling task down into limited models for different simulations (ray tracing, finite point analysis, thermal performance, costing, etc.). A truly integrated modeling tool would probably result in a database that would be both huge and cumbersome. Just think that what we are looking for is a set of tools through which the designer could change the spandrel panel material (and the detail through which it is incorporated into the virtual building), and resulting elevations, sections, rendered perspectives, specifications, cost opinions, and thermal performance would be automatically updated (this is a relatively trivial example which doesn’t really affect geometry, only properties). Demands for computer power increase as the number of objects in the BIM increase, but demands for computer power also increase as the amount of data attached to each object increases. You not only need more memory and processor speed, but better algorithms to optimize use of memory and processing speed.
User interfaces and what might be termed interoperability of objects is a further issue. What you want is something that is relatively intuitive for a knowledgeable user; but what user knows this much about a spandrel? The designer wants to know what it looks like; the detailer wants to know how to detail the glazing; the specifier wants to know materials; the cost estimator wants to … you get the idea. Everyone needs to know a little about the specialized properties that are the specific domain of other specialist, but no one really wants to know EVERYTHING, and I would suggest no one is really interested in dealing with a comprehensive model (and the software interface to deal with it).
The really fundamental issue is that a truly comprehensive BIM fails to comprehend the level of abstraction expressed by a set of construction documents (and associated representations). Our documents do not document every item that goes into a building, but instead documents typical instances (“TYPICAL UNLESS OTHERWISE NOTED”). Moreover, some of the documentation we do is much more diagramatic. We have traditionally be able to show what goes on at a particular point in the building without showing all construction that can be inferred from the typical detail. You really don’t need the comprehensive BIM in order to do construction (even on very large and complex buildings).
There seems to be a move to get around some of the input issues by manufacturer’s providing what might be referred to as “BIM blocks.” I would guess, however, that these objects are of somewhat limited value since those providing the files don’t really know how they will be used. Moreover, those using such components are probably only dimly aware of the properties that are really required by a BIM database. As many firms are finding out, the one who most likely has the best knowledge to design BIM objects is a firm’s specification writer. But, how does the object acquire all the attributes that it should have (spec writers do not know all) to be able to be functional in a real BIM?
As a final comment, I would suggest that despite reliance on the best BIM practices, a building’s constructability and performance cannot be known until a physical object begins to occupy physical space on a physical site. I would further suggest that a building cannot be fully “known” until it has been completely constructed, occupied, and used (kinda gets into life cycle activities). From this perspective, I would suggest that the the BIM database remains incomplete, especially while the building remains in the “virtual” stage. While such a the database may be useful, it may not be as useful as some people might think.
The really sad thing is that I saw some BIM stuff happening 20 to 25 years ago at UCLA, UC Berkeley, Carnegie Mellon, Michigan, Ohio State, and other places in Europe and Australia. The profession did not really want to be bothered and faculties and deans did not want such research activity detracting from “design inquiry.” I guess the first BIM-like application I saw in a real-world context what when a colleague of mine submitted representations from 3-D modeling software (an available commercial package) for a house addition to a building department in the midwest. They wanted no part of it; plans, sections, elevations, details was what they wanted.
Further ranting to come.
IMNSHO, one of the more significant forces behind the push to BIM is indeed “model” related – but it has nothing to do with building modeling: It’s the revenue model.
AutoDesk sold open-ended licenses, good for as long as you wanted to use the software. So to maintain cash flow, they had to enhance the product on a regular basis to entice folks to upgrade. The result was more change and more features than most users wanted or needed, and (I suspect) a counterincentive to perfect the product. There always had to be room for significant improvements that users wanted enough that they were willing to pay for them.
Revit, by contrast, sold only annual licenses (like most spec software), so the income stream was steady, and upgrades weren’t an essential part of the revenue model.
If AutoDesk had simply tried to change its licensing structure to annual renewal, a lot of its users would no doubt have said, “No, thank you, the latest version will do for the foreseeable future.”
So instead, AutoDesk bought Revit. Now it has a plausible way to migrate its customers over to the new revenue model…persuade everyone that BIM (read “Revit”) is the wave of the future!
And it is (the wave of future revenue, at least).
the Novartis project in our office is one model that takes up 13 gigabytes of space; consequently, only a portion of the model can be opened at any one time. And, we don’t do “BIM” the way everyone talks about “BIM”. in our office, its called a “3D Model” because that’s mostly what it is.
the shapes of the spaces (and surfaces) we design simply could not be documented using any other type of technology, but the 3D model is used as the primary construction document for only a few of the aspects of the construction: the exterior skin, the steel structure, usually the glazing, complicated ceiling surfaces (such as in a concert hall) and possibly a few other areas as well. the model is NOT the primary construction document for the entire project, and we carefully define in the specs where the primary design criteria is shown in the model or in the 2D drawings. (Autocad for those). There is no way we’re going to embed specifications data in that model, either, although for our complicated exteriors, the model will do piece counts, rotation (by degrees) and other joint configurations.
The benefits in some aspects are remarkable: for complicated configurations, IF the contractor agrees to use our data, the pricing is absolutely nailed down, and the configurations come out like a jig-saw puzzle. the interferences are checked and remedied before they get to the job site. these are real benefits and there are cost implications.
however, the use of the model does mean one more thing that has to be coordinated; additional time to reconcile the model with the 2D drawings; and someone has to monitor the model and make sure that folks have the correct version. And, the model is used only by a few tiers of subcontractors – eventually everything comes down to two guys holding up a panel so that another guy with a power fastener can install it incorrectly because he put the wrong fastener in the gun. And, there is NOTHING a 3D model can do to fix that.
Wayne, if GSA is using Revit, they are not using BIM, since Revit is not BIM software --Revit is 3D modeling software, and its used as another component of the documents. BIM is what Boeing is doing – for their airplanes, not their buildings. BIM is also what telecom suppliers use, and automobiles.
now wait. Revit does hold more data than just 3D modeling and can therefore generate things like door schedules, AND if you set up rooms etc. correctly it can tell you things about the room (objects in the room or not etc) So A perfect BIM software? No. capable of being a BIM yes.
GSA uses Revit or other product as part of their building information modeling. At least that is what they were doing at AIA 2007 Convention in San Antonio. Disney Studios gave the most reviting (pardon the pun) demo of their revamped space mountain ride. Both were using 3D software for error trapping. The entire education session was included under the BIM umbrella.
That is my story and I am sticking to it.
I just spoke with a colleague at Disney and he said they were using 4D (that’s what he called it) for their rides only, and for architecture work they are using Autocad (2D) and Speclink for their documents. GSA on their website states that they are moving from “3D to 4D to BIM” and “encouraging” their providers to use 3D.
I think the BIM notion might become simple, if staffed correctly with a diversely talented team. But it demands a level of discipline and specificity that many practitioners don’t want to dirty their hands with.
For example, a room is an object with attributes, such as finish elements, and attachments, such as equipment data. The finish elements tie to specification files via reference keynotes that are hot links. The specification files in turn tie to products via hot links to product data sheets. The entire collection of files resides in a multifile BIM. The facilities manager that inherits this terrabyte of stuff can access it to see what he or she owns, where it is located, who supplied it, and what they have to do with it. If they’re really anal, they’ll maintain it, and it may be worth the effort.
Much of this could have been accomplished 8 or 10 years ago in ADT or Triforma with a clever applications programmer. It still isn’t being done much, because there are so few people who have the technical expertise to pull it off, or because it isn’t worth the fees to assemble it, or because facilities managers don’t care that much. But some do, and think it is worth the fee investment, and are doing it, or will soon.
BIM is supposed to be more than a 3D database with references and hot links. If it is truly multidisciplinary, the virtual object also includes structural, thermal, and perhaps even chemical properties. Under various simulations, the object, or assembly of objects, behaves like the real object that is being modeled.
A BIM that includes the various characteristics related to flamability and fire resistance would be useful in the design phase to model safer buildings and during the occupancy phase to evacuate the facility during a fire and actually fight the fire. I saw simulation software for the spread and growth of building fires beginning to be developed in the mid '90s.
What about acoustical simulations? Bose developed excellent software for this in the early '90s. A comprehensive BIM file would include the ability to add the necessary properties to objects to permit a proper acoustical simulation.
I would concede that Revit may be “baby BIM” although I saw software that could do some of what Revit does (and has a similar interface) in the mid '80s (does anyone but me remember VersaCAD?). To properly implement even “baby BIM” can be complicated and time consuming; how will the construction industry implement real BIM?
Incidentally, Ralph may remember how to make blue prints, but I have drafted with ink on linen… producing base media for facility management on a telephone company facility… Does this mean that I was BIMming back then?
Ann,
I humbly sit corrected.
Wayne