AEC Tech News #97 (May 14, 2003)

13 May, 2003 By: Lachmi Khemlani

I have devoted several recent issues of this newsletter to Building Information Modeling (BIM), in light of the current aggressive push by AEC technology vendors to replace CAD with BIM as the de facto standard in the industry for integrating architecture, engineering, and construction. We have looked at the BIM perspectives of the two leading vendors, Autodesk and Bentley, and at how they differ from each other on various aspects, such as whether the building model should be centralized or not; how different building applications can interoperate; whether the focus of BIM should be a tool or a platform; and whether a good BIM solution can be built on top of a CAD platform or not.

In addition to Autodesk and Bentley, there is a serious third contender in the BIM race. This is Graphisoft, whose 20-year-old solution, ArchiCAD, has actually had building modeling capabilities from the start, and can therefore be regarded as a pioneer in this technology. This issue presents and analyzes Graphisoft's perspective on BIM.

Graphisoft's Position on BIM
If Autodesk and Bentley represent two opposing camps in their approaches to BIM, as evidenced by their recent BIM debate discussed in Issues #95 and #96, Graphisoft lies closer to Autodesk's side than to Bentley's.

The focus of Graphisoft's BIM solution, ArchiCAD, is also a tool similar to Autodesk Revit rather than a general-purpose CAD platform such as MicroStation. Just like Revit, ArchiCAD was developed to model buildings in 3D right from the start, so its underlying data model deals first and foremost with building entities rather than geometric entities. A single building object is described only once in this data model--whether it appears in a plan, elevation, or 3D view--leading to a model that is always consistent. Thus, like Revit's, ArchiCAD's building model is centralized, with integrated data, unlike Bentley's federated approach, which is based on the distribution and aggregation of building data across multiple applications.

With respect to interoperability, Graphisoft has not thrown open ArchiCAD's file format, as Bentley has done with MicroStation's DGN. Instead, Graphisoft has taken a lead role in the IAI's interoperability effort and relies extensively on the non-proprietary IFC file format to interoperate with other building applications. This also sets it apart from Autodesk, which relies less on file formats such as IFC and, instead, emphasizes other means such as ODBC compliance (as in Revit) and APIs (as in AutoCAD and ADT) to connect applications with each other.

Since ArchiCAD was BIM-enabled right from the start, Graphisoft happily avoids the evolutionary-versus-revolutionary conundrum faced by its formidable competitors. Those using ArchiCAD are already doing BIM rather than CAD--even though the term BIM hadn't been invented until recently--and don't have to do anything different now. In contrast, Autodesk has to urge its customers to switch to Revit to get the real benefit of BIM, and Bentley has to show its customers how to do BIM with the same tools with which they were previously doing CAD.

Analysis One cannot argue that Graphisoft's BIM solution is superior to those of its competitors just because it was developed and deployed first. Older is not necessarily better, particularly when it comes to technological innovations and even more so in the arena of software. Newer and better concepts for programming, data modeling, and user interface are constantly emerging from the field of computer science, and software written from scratch can incorporate these latest concepts. There is also a creative license when starting with a clean slate, which can often lead to innovative approaches to existing problems. Consider the ease-of-use of the newcomer SketchUp for 3D modeling compared to the established 3D software such as Autodesk VIZ and form•Z. Similarly for building modeling, a newer application such as Revit incorporates many smart features that would be challenging for established software such as ArchiCAD to replicate without a major rewrite of code.

At the same time, a more established software has the advantage of being tried and tested and proven to work. Thus, ArchiCAD may not have all the latest bells and whistles, but it does have satisfied customer testimonials and stories of successful ArchiCAD implementation on large projects that have been realizing the benefits of BIM throughout the product's 20-year history.

A case in point is the ongoing Eureka Tower project in Australia, designed by the firm, Fender Katsalidis Architects. When complete, this will be the tallest residential building in the world. David Sutherland, Director of Planning for the project described the use of ArchiCAD as being the underlying basis of the design approach to the Eureka Tower (and all projects within the firm's practice), as it encouraged the prototyping of buildings and the sharing of constructional information, and enabled the building to be simulated in 3D throughout the design and documentation phases. All the required 2D, 3D, or text-based information, including approximately 1,500 A1-size construction drawings to date, were derived through automated processes from the single 3D virtual building model. This is certainly compelling evidence that the benefits of BIM, as described in Issue #95, are real, and can be realized through the deployment of ArchiCAD.

There is one aspect, however, that I think Graphisoft needs to be concerned about as a contender in the BIM race. Starting with its very name, ArchiCAD has been positioned and is perceived as an architect's tool. But as Building Lifecycle Management (BLM) takes center stage and the integration of building disciplines becomes more critical, the efficacy of a BIM solution will be judged by how well it addresses the design needs of all the disciplines. All the architectural, structural, mechanical, electrical, plumbing, and any other building entities should ideally be designed with the same BIM tool or suite of tools, otherwise the very term BIM is a misnomer. By giving primacy to architectural design, Graphisoft cannot hope to attract other building design professionals to use its product and produce a truly integrated BIM solution.

Conclusions
It is a pity that, despite pioneering the single building modeling technology--which it calls the Virtual Building--20 years ago, Graphisoft now appears more like a latecomer that has jumped on to the BIM bandwagon. In contrast, by introducing the term BIM and evangelizing it as part of its aggressive marketing campaign for Revit, Autodesk has cleverly positioned itself as the visionary company that is propagating much needed reform in the building industry.

Hopefully, it is not too late and ArchiCAD can gain the momentum and visibility it deserves as AEC professionals becomes more aware of the importance of BIM and its potential benefits to the industry.