Old Standard Taps BIM Data for New Uses16 Aug, 2004 By: AIA ,Rick Rundell
ODBC translates information for a growing list of architectural applications
Designers have been rapidly adopting BIM (building information modeling) technology, so more and more users want to cull BIM data for use in related applications, including energy analysis, specification management, visualization, and rendering.
Part and parcel of this process is how best to retrieve the information held within a building information model. The options are plentiful because, as we've often observed, the nice thing about standards is that there are so many to choose from! Among adopted or proposed standards for communicating building information are IFCs, various flavors of XML, DWG, DWF, DXF, and (remarkably) even PDF.
This month's article explores how one well-established and widely adopted standard, ODBC, is helping transfer building information from the Autodesk Revit building information modeler to other applications.
The ODBC (open database connectivity) standard is a database access method that provides a vendor-neutral common ground between applications and databases. Essentially a vehicle for accessing data from relational tables of rows and columns, ODBC has been used in commercial applications for more than a decade and is a proven, established data transmission method. ODBC uses a middle layer, called a database driver, that acts as a translator between an application and a database. As long as the software programs on both sides of the driver support ODBC, specialized programming or interfaces are not necessary. That reduces the cost of the application integration and ongoing product support.
CAD applications contain building geometry and (often) building object data. Consuming this data places a substantial post-processing burden on the receiving application to derive non-object data building information such as material quantities or program areas from the geometry. It requires communicating a relatively large amount of data -- a lot of work on the part of the receiving application -- and an elaborate integration protocol supporting both geometry and data.
True building information modeling tools track building information directly. They communicate material quantities and other building information in a straightforward and compact way to other applications that can consume the data directly.
Ironically, for the most sophisticated building information modeling tools, the relatively old ODBC standard turns out to be a particularly suitable integration approach for applications such as cost estimating, quantity surveying, and specification management.
Following are two good examples of how ODBC standards facilitate data transfer from Revit to other applications (figure 1).
Figure 1. Using the ODBC standard, the Autodesk Revit building information modeler shares information with data-centric applications such as e-SPECS (specification management) and ITALSOFT (cost estimating).
One software vendor that used ODBC to connect its product to Revit is Portland, Maine-based InterSpec. The company's specification-management product, e-SPECS, automates the preparation of project specifications for architects. Typically, e-SPECS scans and extracts product and material requirements from whatever object data is available in AutoCAD DWG drawing files, and the user supplies whatever is missing. Recently, InterSpec linked e-SPECS directly to Revit's parametric database via ODBC. This tight integration ensures that the building model and project specifications remain in sync. For instance, if you add a door, window, or other building object to the Revit model, the e-SPECS project specification manual is updated with the appropriate information. Or if you change a brick wall in the Revit database to a concrete wall, the e-SPECS project manual replaces the unit masonry section of the spec with a concrete section.
InterSpec's president, Michael Brennan, says, "This direct link between e-SPECS and the Revit database generates more cost savings by guaranteeing that the information in the project specifications matches the current state of the building model. Our e-SPECS for Revit customers can benefit from Revit's inherent ability to produce high-quality, consistent, always-coordinated design information --information that is also in sync with the project specifications."
Similarly, ITALSOFT, located in Stanghella, Italy (Italian-language site), leverages ODBC to dynamically link Revit to its cost-estimating software. ITALSOFT's system initially maps building items to Revit types during project setup (figure 2). For example, a partition wall type from Revit contains bricks (calculated by volume), plaster on both sides (calculated by surface), paint (calculated by surface on one or both sides), and labor (calculated by hours).
Figure 2. ITALSOFT dynamically links Revit to cost-estimating software.
ITALSOFT then uses the ODBC connection to Revit to determine the number of instances of each type that exist in the project and calculates project costs according to the prices established for those items. Like the e-SPEC example above, the direct ODBC connection between ITALSOFT and Revit ensures that cost estimates produced by the software are in sync with the building model.
Some Standards Are Superior
Software vendors leverage many standards to enable the exchange of building information. But all standards are not created equal: Different standards have evolved to suit particular sets of requirements. As it turns out, ODBC -- an "old" standard by Internet reckoning --is well-suited to integrating data-centric applications with building information modeling.
At the end of the day, customer and industry needs are the driving forces behind how the industry will use standards to extend building information modeling to other applications in truly useful ways.