CBS Newsletter
Summer 1997
pg. 4

Building Software Tools with Interoperability

Vladimir Bazjanac, Ricardo Goncalves and Manfred Koethe.

Vladimir Bazjanac (left) chairs the open IAI research advisory committee meeting held at San Diego in June. Next to him are Ricardo Goncalves, UNINOVA, and Manfred Koethe, DEC.

Recently, architects and engineers (A&E) have begun to make building design and energy simulation software an indispensable part of their toolbox. Most A&E firms now use commercial, off-the-shelf design assistance programs. An increasing number of building professionals are also using software developed at the Center's Building Technology Program: the whole-building energy simulation program DOE-2 to design more energy-efficient structures, RADIANCE for simulating lighting designs, and WINDOW for calculating the thermal performance of window systems. A number of other energy-related programs for buildings are also on the market. However, all of these face a barrier to wider distribution: their inability to exchange data easily. Each program defines a building differently. To use building data generated by one program in another, the user has to re-create the building specifications in a new data format-a time-consuming process.

A new organization, the International Alliance for Interoperability (IAI), is working to change this. "The aim of the IAI is to create an environment of interoperability for building software tools," says Vladimir Bazjanac, a scientist in the Center's Building Technologies Program who has been involved with IAI since its early days. "We are working to establish a standard data model of a building which can serve as common ground for the exchange of information among all parties involved in the conception, design, construction, operation and use of the building."

To accomplish this, the IAI is developing a standard object-oriented model of buildings. IAI members include the companies and institutions that develop and distribute major building design and energy simulation software programs, and they are working to adapt their software to comply with this standard. The IAI's standard data model is called Industry Foundation Classes (IFCs). By incorporating IFCs into their own software, design software manufacturers are giving their products a common data format that will allow users of different programs to exchange information easily.

Among the IAI's 400 members are the major CAD vendors: Autodesk (AutoCAD), Bentley (Microstation TriForma), and Nemetschek (Allplan FT). Berkeley Lab, through Building Technologies Program Head Steve Selkowitz, Bazjanac, and others, was one of the 11 founding members of the IAI. The Pacific Northwest National Laboratory, the General Services Administration, the Department of Defense and the Department of Energy, through the national labs, are also participants. Selkowitz is on the Board of Directors of IAI's North American chapter.

The Center's Building Technologies Program became involved in 1994, when Autodesk began working with other software manufacturers to address the interoperability problem. Another founding member, Honeywell, approached Selkowitz, proposing a partnership to develop components of the software that would demonstrate the value of the IFC concept. After the demo was judged a success at the 1995 Architecture Engineering Construction Systems Show in Atlanta, the founding members reformulated the IAI as a non-profit, open consortium which now has 400 members organized in six chapters around the world.

Design software manufacturers are giving their products a common data format that will allow users of different programs to exchange information easily.

Working with their industrial partners, programmers at Berkeley Lab meet to write an interface to building simulation programs developed here, including DOE-2 and RADIANCE, so that they are IFC-compliant. Then it will be possible to take the description of a building designed using AutoCAD, for example, transfer it to DOE-2, and test the design's energy efficiency. "All of our simulation tools depend heavily on the description of a building's geometry," says Bazjanac, "and 80 percent of the simulation effort is describing the input. Thus IFCs could save us a lot of time and make it possible for an energy consultant to do the work for a lot less money. Also, these tools can improve the accuracy of the simulation by eliminating human error from the process of translating the building description."

IAI has released Version 1.0 of IFC, which contains the building geometry model; the three most widely used commercial CAD programs are in the process of becoming IFC-compliant. The IAI plans to release Version 2.0 later this year. Through regular releases, IAI expects eventually to bring all new software into compliance as it appears on the market.

—Allan Chen

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Vladimir Bazjanac
Building Technologies Program
(510) 486-4092; (510) 486-4089 fax

Visit the IAI Web site.

This work is supported by DOE's Office of Building Technology, State and Community Programs.

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