New tools deliver BIM data: building model yields valuable information - AEC tools: master the architect's desktop - including Autodesk's Revit and Architectural Desktop 2004, Bentley Architecture 8.1

CADalyst, Dec, 2003 by H. Edward Goldberg

All the recent hype about BIM (building information modeling) piqued my curiosity about just how capable this generation of software is at producing useful information. Conceptually, BIM, a term coined by Autodesk and promoted by Jerry Laiserin, is a 3D virtual building model. Data associated with the model contains information on all building components. This data is available for use throughout the entire building cycle--the design, construction, and facility management stages of a project.

To my surprise, I uncovered several software solutions that extract information from a BIM. This article discusses some of these options, specifically Autodesk's Revit and Architectural Desktop 2004, Bentley Architecture 8.1, Graphisoft's ArchiCAD 8.3, and InterSpec's e-SPECS.

UNDERSTAND THE FORMAT

A better understanding of the nature of these information solutions requires familiarity with the CSI MasterFormat and UniFormat numbering systems, the IFC (Industry Foundation Classes) standard, and the ODBC (open database connectivity) format. The CSI MasterFormat standard is a 16-division, material-specific organizational format. The UniFormat, a more detailed numbering system, breaks building systems into categories such as foundation, superstructure, shell, and interior construction, and into subcategories such as floor and roof construction and exterior walls and windows. AEC designers use both systems to organize documents and specifications. See www.csinet.org/technic/uflite.htm#A for a more complete explanation of these formats.

The IFC standard was developed by the IAI (International Alliance for Interoperability) to handle 3D file data. Major CAD vendors helped develop the standard and the tools to support it. The IAI is a division of the ISO (International Standards Organization), the body that controls the IGES and STEP data standards.

The IFC system is a data representation standard and file format used to define architectural and construction-related CAD graphic data as 3D real-world objects. Its main purpose is to provide architectural CAD users with the ability to exchange data between complementary applications such as CAD and estimating tools. The IFC system provides a set of definitions for all object element types encountered in the building industry and a text-based structure for storing those definitions in a data file. It uses a plain text file, the only truly universal computer data format. Individual CAD developers store data in whatever compact binary file format best suits their system. To implement the IFC standard, each CAD company must create programming within its own software structure. The developers provide Save As IFC and Read IFC commands, which map the IFC object definitions to their CAD system's representations of these objects.

As of this writing, Graphisoft and Bentley have implemented and enabled export capabilities for IFC 2. Bentley's building applications support 2.x, the latest version of the IFC standard. In addition, Timberline's estimating software, CAD Integrator Module, supports the IFC 2 standard for import of IFC data from any IFC application.

ODBC format is a standard database access method developed by Microsoft. The goal of ODBC is to enable access to any data from any application, regardless of the DBMS (database management system) handling the data. ODBC inserts a middle layer, called a database driver, between an application and the DBMS, which translates the application's data queries into commands that the DBMS understands. Both the application and the DBMS must be ODBC-compliant--that is, the application must be capable of issuing ODBC commands and the DBMS must be able to respond to them.

GRAPHISOFT'S ARCHICAD 8.3, RCC UNIFORMAT DATABASE

A compelling third-party software solution that leverages BIM recently appeared on my radar screen. Rich Creveling, a programmer in Colorado with a construction industry background, created the RCC UniFormat Database, a product that bridges the gulf between 3D models created in ArchiCAD 8.3 and Timberline Estimating Software. RCC's integration with Timberline estimating software via IFC 2 exchange is a significant and powerful innovation. The RCC Favorites Library component of the RCC UniFormat Database is now included with ArchiCAD 8.3 (figure 1).

[FIGURE 1 OMITTED]

The RCC includes a large body of architectural content such as beams, columns, doors, slabs, walls, windows, floors, decks, and roofs. As an example of its vastness, the library defines more than 80 types of typical wall composites. Using the IFC-based Timberline CAD Integrator, you can leverage building models created with the ArchiCAD RCC Favorites Library to derive detailed commodity-level construction cost estimates in seconds.

Because the RCC UniFormat Database and accompanying object library definitions support the IFC 2 standard, they provide machine-readable architectural content for automated cost estimating. This data also features attributes you can use to integrate purchasing, scheduling, and accounting applications. According to Creveling, he has had discussions with other design software vendors, including Bentley Systems, about developing similar object libraries for their products. He's happy to continue to work with Graphisoft because he believes that Graphisoft has done a great job of developing ArchiCAD from the ground up to support IFCs.