AEC From the Ground Up-The Strengths of BIM31 Oct, 2005 By: AIA ,H. Edward Goldberg Cadalyst
BIM pays off in productivity.
AFTER SEVERAL YEARS OF intensive campaigning, primarily by Autodesk, the BIM (building information model) acronym has taken hold. Every major architectural software developer now claims to have a BIM software solution. In addition, NIBS (National Institute of Building Sciences) is developing a national BIM standard, the University of Georgia recently held a BIM conference and even the AIA has created a group to investigate this technology. Despite all this emphasis on BIM, few analysts address the real benefit of BIM software for the professionals who use it.
At a recent meeting of the NIBS National BIM standard, more than 70 participants, including me, discussed what kind of information we would like from BIM. Each participant had a different idea. Unfortunately, few of the participants were professionals who actually use BIM software on a daily basis.
In my opinion, the BIM discussion has become very confused. Autodesk, Bentley Systems, Graphisoft, VectorWorks and Gehry Technologies all offer architectural-specific BIM programs that help users more productively and accurately create construction documents. BIM lets users insert information such as product manufacturers and costs into the file, but 2D CAD programs have done this for years. BIM programs use 3D modeling to increase productivity in creating and coordinating elevations, sections and calculating volumes, and some solutions handle interference detection and cost estimates.
To many, BIM is defined by this ability to extract and develop data in design scenarios, cost estimates and facility management. This use of BIM is highly touted, but in my mind is overemphasized. The major advantage to architects and engineers comes from increased productivity in creating the design and construction documentation, and not from the inserted information. Besides, the firm that inserts the information probably won't be paid for that addition to the documents.
Just as professionals who first implemented CAD in the 1980s benefited financially from that digital revolution, the benefit to professionals who use BIM software most likely will come from being more competitive in the marketplace. Some companies claim a 30–40% increase in productivity compared to standard 2D CAD. For more information, see Autodesk's study at http://images.autodesk.com/adsk/files/Revit_BIM_ROI_Jun05.pdf and Graphisoft's at www.graphisoft.com/company/press_zone/roilaunch.html.
Most recently, the GSA (General Services Administration) indicated that it wants initial space planning information for all its 2006 projects to be exportable in IFC (Industry Foundation Classes) format.
All the dedicated architectural BIM or virtual modeling software solutions from the major software publishers—Autodesk, Bentley Systems, Graphisoft, VectorWorks and Gehry Technologies—are very capable.
Autodesk's Architectural Desktop and Building Systems are based on AutoCAD. Together, their similar user interfaces, interaction and native DWG format make up a complete 3D architecture and MEP (mechanical, electrical and plumbing) solution. These programs rely heavily on automated entity creation. A new feature in Architectural Desktop 2006, AEC Project Standards, allows the user to set up drawing files that contain components such as doors that, when changed, synchronize throughout the entire project set of drawings. Architectural Desktop's Project Navigator coordinates all the drawings in each project, and its Detail Components feature increases detailing efficency. Autodesk Building Systems is similar to Architectural Desktop, but is dedicated to MEP engineers (figure 1). Because these programs work so well together, mistakes such as pipe interferences and poor light locations are eliminated. These products have IFC export capability.
Figure 1. Interference detection, such as this example from Autodesk Building Systems, isolates mistakes before they happen in the field.
Autodesk Revit Building and Revit Structure (figure 2) were built specifically to use a single building model file. It's interesting that programmers who developed 3D software for the mechanical design industry originally conceived this software. These programs are very intuitive and easy to learn. Because Autodesk Revit stores everything in a single file, changes made to any view instantly migrate throughout the construction document set. For architects who are new to CAD, this software is an excellent choice. Many large architectural firms such as HOK, SOM and RTKL use Revit Building and Structure. The Revit programs are currently in the process of gaining IFC export certification.
Figure 2. Revit Structure helps engineers structurally analyze part or all of a building with bidirectional linking to third-party analysis software such as ETABS, RISA-3D and ROBOT Millennium.
Bentley Systems believes that by applying information and model-based technology solutions so that drawings and reports, design analysis, schedule simulation, facilities management and the like are completed automatically, its users will be more productive and profitable. Go to www.bentley.com/bim to read more on Bentley's BIM views.
Bentley Architecture (figure 3) is the architectural application in Bentley's multidisciplinary suite of BIM solutions. An object-oriented CAD solution, it's based on the MicroStation platform, as are its companions for structural and building systems engineering. MicroStation (and AutoCAD) operators can easily become proficient with Bentley Architecture. Bentley offers full DWG support to integrate with AutoCAD and Architectural Desktop users on mixed-platform projects. Bentley has completed several studies on productivity, and one of its users, CH2M Hill, has had great success with BIM. Company representatives report that "BIM results in 35% improvement in overall productivity, with a 65% improvement in design team efficiency and a 48% reduction in required drawings."
Figure 3. Bentley Architecture combines drawing coordination with architecture-specific routines to give a big productivity boost.
Because Bentley has one of the most complete BIM solutions for architects and engineers working on a single platform, and supports those on other platforms through standard formats such as DWG, PDF, CIS/2 and the IAI IFCs, it's appropriate for multidisciplinary teams and complex projects. To augment its portfolio, Bentley formed a partnership with RAM International, a provider of structural design software, to distribute RAM's products for structural engineering. Bentley has IFC export capability and was an advisor to the GSA on IFCs.
Digital Project from Gehry Technologies is probably the most advanced BIM software available, and the most expensive. Digital Project Release V1, R2 is built on CATIA V5 Release 15, the latest version of CATIA from Dassault Systèmes (www.3ds.com). Digital Project supports the lifecycle of construction projects—from design and engineering to fabrication, construction project management and on-site construction activities—in a collaborative digital environment. It integrates with Primavera so users can link 3D BIM components to Primavera and simulate activities in 3D using 4D navigation. Gehry Technologies promotes design and construction methodologies that view 3D models of construction information as components of the project contract documentation. These methodologies, referred to collectively as digital practice, include not only the technical aspects of tracking data, but also the contractual and procedural advances needed. According to Gehry Technologies, digital practice is realized on building projects through several interrelated project activities, such as product coordination and control, building performance, cost estimating, 3D to 2D integration, digital fabrication and onsite integration. Digital fabrication, which supports the direct integration of design and engineering data with fabrication activities, is the software's strongest point. Digital design information is provided directly to fabrication shops to provide the dimensional specification and component placement information.
ArchiCAD (figure 4), the oldest of the dedicated architectural software solutions, is offered on both the Macintosh and PC platforms. Although Graphisoft considers ArchiCAD BIM software, it refers to it as a virtual modeling program, which is the same thing, just a different marketing approach. As do the other programs mentioned here, ArchiCAD features routines dedicated to quickly modeling buildings and building elements in 3D. Graphisoft's family of products also includes GS Constructor, a product line for design/build firms, construction firms, engineering firms and consultants. This product set, which includes GS Constructor and GS Estimator, allows companies to perform model-based calculations for scheduling, estimating and purchasing, and provides a comprehensive platform to manage an entire construction project. Constructor also offers a next-generation MEP modeling environment as well as a structural modeling library. ArchiCAD has been a leader in IFC import and export for information transfer between 3D programs and is IFC certified.
Figure 4. All BIM solutions provide automatic sections and other routines, such as this one in ArchiCAD, that can increase productivity by as much as 35% for average users.
Although the least expensive program of all the solutions mentioned in this article, VectorWorks 12 has 2D and 3D productivity enhancements you'd expect in a more costly BIM software product. These include intelligent object technology—when you insert a window, the wall automatically breaks, and if you move the window, the wall automatically heals. And because objects in the Architect module display in 3D as well as 2D, when you change an object in one view, it automatically updates in the other so plans and models are perfectly coordinated. VectorWorks 12 also includes freeform 3D NURBS modeling, which isn't available in many of the other programs. It's easy to turn 3D design concepts into 2D production drawings using the Floorplan command. Other excellent tools include roof design, seating layout, workgroup referencing, redline tools, the ability to create precise 2D topographical maps and 3D terrain models from surveyor's data, energy analysis,solar animation and realistic visualization. VectorWorks does not include IFC export, but Nemetschek expects to add that soon. The program is available for both Windows and Macintosh operating systems.
The future of the BIM is wide open. As these programs mature and are accepted by the industry (including the building permits department), we can expect to see code checking, estimating, PLM and the like become important features. Though the programs have some of that capability now, their real benefit comes from increased productivity.
H. Edward Goldberg, AIA, NCARB, is a practicing licensed architect and AEC industry analyst. Ed's full-length book, Autodesk Architectural Desktop 2006: A Comprehensive Tutorial (Prentice Hall; www.prenhall.com) is now available. Contact Ed for online Architectural Desktop training sessions delivered directly to the desktop. Visit www.hegra.org for more information, or e-mail email@example.com.