CADENCE AEC Tech News #103 (August 14, 2003)

13 Aug, 2003 By: Lachmi Khemlani

In This Issue: Readers Weigh In on BIM

  • Evaluating Different BIM Solutions
  • Divergent Professional Views on BIM
  • Conclusions
  • Relevant Links

I have devoted several issues of the AEC Tech News to presenting and analyzing various vendors' perspectives on Building Information Modeling or BIM (see Issues #90 and #94-97 at In my recent cover story for CADENCE magazine, "Should We BIM?" (, I also looked at how the recent BIM phenomenon raises the state of the art in AEC, and evaluated how solutions for different aspects of building design and construction tie into the BIM concept. I have received numerous emails from readers in response to these articles. Some have written in to share their professional views on BIM and their experiences with various BIM solutions, while others write to ask for more information on different aspects of BIM. This issue of the AEC Tech News is devoted to capturing the users' perspectives on BIM by printing a selection of these reader responses (edited for conciseness). As you will see, critical issues are raised, which should be useful to AEC professionals and their technology vendors alike.

Evaluating Different BIM Solutions

Topping the list of issues and questions I get are those related to specific BIM solutions such as Autodesk Revit, ArchiCAD, Autodesk Architectural Desktop (ADT), Bentley Architecture, BOA, and VectorWorks ARCHITECT. Many readers are currently evaluating different BIM offerings, and are looking for insights on which one to adopt, as the following sampling shows:

1. "I am an architect with a small architectural practice and we are currently evaluating 3D CAD software to replace 2D drafting with AutoCAD 2002. We have examined Revit 5.0 and ArchiCAD 8.0, but find them very expensive. When we read your review of BOA in CADENCE magazine we felt it sounded very interesting, since the company claims that it can handle large projects without losing accuracy. Do you believe that BOA could be an alternative for Revit?"

2. "We have been using Revit on a couple of pilot projects, and the results have been mixed. Our architects continue to struggle with the software's complexity and its effect on our ability to produce construction documents as quickly and efficiently as possible. Do you know of any firms that have been using the Revit program for at least a couple of years? I would be interested in contacting them as we pursue a decision on which way we need to be going."

3. "We manage the facilities of a four year university. Our position requires us to prepare drawings for small and some mid-sized renovations. We are looking at changing from ADT to Revit, and I wanted to inquire what you think would be the best way to go. We have used AutoCAD before, but not to a great extent. When we began implementing ADT, we got so frustrated that we just ended up using ADT as AutoCAD. What would you suggest?"

4. "Do you really believe that BIM products are going to be capable of the modeling sophistication of form.Z and 3ds max? I did not see that with ArchiCAD or VectorWorks two years ago, or ADT presently, and I still have an evaluation copy of Revit 5.0 to look at. I am trying to digest all this and decide what solution to look into for myself and/or present to our office. Currently, modeling, designing, and investigation work best in form•Z with production in AutoCAD, but what should I be looking at two to three years from now?"

Clearly, most practices are taking a serious look at Autodesk Revit, as they consider the change from 2D CAD to 3D BIM. A few practices have already completed their evaluation process, and the results are mixed. Some appreciate the smarts and ease-of-use of Revit, while for others, alternative solutions have come out on top, as this selection of messages shows:

5. "Revit is much easier to work with compared to ADT."

6. "As a user of ArchiCAD and an ex-subscriber to Revit, I can say that ArchiCAD is a far more elegant and flexible solution to BIM than Revit. ArchiCAD has been around much longer, and it shows when using the software. In my tests, Revit chokes on the larger projects. Even simple changes on a large project take 12 to 20 seconds to implement and this creates havoc in the CD phase. Also the Teamwork concept (multiple people working on the same project) works much better in ArchiCAD."

7. "In my practice, I have used DataCAD, MiniCAD/VectorWorks, AutoCAD, and Revit to varying degrees. I was using VectorWorks just prior to signing on with Revit, and I decided to try Revit (prior to its Autodesk acquisition) due to its low entry cost. I was also intrigued by their BIM format. We used Revit roughly from V2.0 through V4.5. Unlike most firms, we actually did produce working drawings using Revit, and the BIM format did have its advantages in drawing coordination, and so forth. But since last year, we have returned to VectorWorks. The advantages to VectorWorks' separate-yet-equal 2D and separate file systems cannot be overstated. We enjoy nearly all of the same advantages of Revit-style BIM, yet we retain the control of the software as the designer. We also do not suffer from the software locking up and forcing the architect or designer to find a work around."

Divergent Professional Views on BIM

There is a growing recognition in the AEC industry that a better integration of multi-disciplinary workflows is needed, which calls for an integrated BIM solution that can support not just architecture, but also other aspects of design and construction.

1. "As an architect engaged in a practice specializing in sustainable design (another 'emerging' trend), the key to progress in the next five years is truly integrated design. And it is not enough to get the A in AEC convinced; the engineers have to abandon the status quo as well. A stable platform is something we designers really need because the distinctions between the roles of architect, engineer, and contractor are starting to blur. 2D CAD was great in the days when building services engineering was simply an input/output problem. Building envelopes and air handling systems are much more tightly knit components now."

2. "I'm an Application Systems Manager working in pre-engineered metal buildings, and my firm has been dealing with integration aspects for a very long time. Our product is the building. We need the data to manufacture it and the customers need the data to erect it. Connecting design-build to manufacturing requires BIM--we can't afford the 30 percent loss you speak of. We have been using in-house developed configuration and engineering systems to integrate our contractors, engineering services, and manufacturing since the early 1980's. In the world of pre-engineered metal buildings, the BIM kind of system thinking is very strong."

While for some engineers, the integration benefits afforded by BIM seem a strong incentive for adopting it, as in the message above, not all engineers are convinced about the necessity of the 3D aspect of BIM. See this message below:

3. "The architects seem to embrace the 3D model environment for presentations, but engineers do not need it. We neither have time nor money to produce a 3D representation of our design effort, and it adds little value in providing information to the contractor who builds the building."

Clearly, the shift from 2D to 3D is onerous and is probably going to be one of the biggest obstacles in BIM implementation, as evidenced by the following:

4. "Our office is going through the pains of deciding which program we as an office will utilize. We are in the process of evaluating both Revit and ArchiCAD. Our biggest hurdle is getting the mind shift from 2D to 3D. Our whole process of doing architecture needs to change--from the day we get a project to construction. There is more to it than just a program change. The way we work, the type of deliverables, client expectations, and so on are all subject to change. At least for some people in our office, this is a very frightening prospect."


The acquisition of Revit by Autodesk in April last year triggered a chain of events in the AEC industry that led to the aggressive promotion of BIM by the software vendors and to the labeling of their products as BIM solutions rather than CAD. If BIM takes off, the Revit acquisition will be seen in hindsight as the primary catalyst to BIM adoption. This doesn't necessarily mean that all AEC firms are going to settle on Revit as their BIM application; other alternatives are being explored, and traditional solutions, such as ArchiCAD, Bentley Architecture, and VectorWorks ARCHITECT, are being looked at in a new light. The state of the art in AEC has undeniably been raised, and better technology should follow.

As of now, it doesn't seem as though any one BIM solution will enjoy the kind of dominance in the BIM arena that AutoCAD has hitherto enjoyed in CAD. As I have pointed out in my earlier articles, the playing field has been leveled out, and all the major AEC software vendors are now aggressively riding on the BIM wave. The question of "Which is the best BIM solution?" that I get asked so often can only be answered by undertaking extensive research and analysis. Also, there might not be a "one size fits all" policy when it comes to BIM. All those looking at BIM implementation need to go out and diligently test evaluation copies of all the available solutions to see which one best works for the kinds of projects, processes, and standards in their practices. There are no shortcuts, unfortunately.

If you have any thoughts on or experiences with BIM you'd like to share, drop me a note. I'll publish these responses in a future issue.

Relevant Links

Autodesk Revit:


Autodesk Architectural Desktop:

Bentley Architecture:


VectorWorks ARCHITECT: