BIM and the Building Information Model (AEC in Focus Column)

30 Apr, 2007 By: AIA ,H. Edward Goldberg

Applications evolve, as do the definitions of BIM.

Recently, I was interviewed by an analyst researching the building information model concept for the AEC/FM (architecture/engineering/construction/facility management) industry. This analyst asked experts what they thought BIM (building information modeling) meant. Here in the United States, groups such as the National BIM Standard and the AGC (Associated General Contractors of America) have their own definitions, as does Autodesk, Bentley and Nemetschek. I have my own definition, which I believe is a compendium of some of their definitions as well as my own take on the subject.

I define the building information model as all the information about a project within its property lines to the center of the earth and infinitely to the sky, from its inception through construction and use until its final decommission and elimination.

When I say "to the center of the earth and infinitely to the sky," I don't mean it quite literally. But I do reference all the necessary information under a project, such as utilities, earthquake, floodplain and ground compaction information, and all of the information above the building, including as zoning, weather, taxes and noise zones. I see the BIM moniker as a poor acronym for what I consider a 3D graphic information system that will eventually unify all the computerized information contained in all of our databases pertaining to my above definition. I foresee a time when users will be able to cull any information they need from a building project, pulling that information automatically from various private and governmental databases. How soon will this happen and whether it will be one product are interesting topics.

The building information model continues to evolve, and pieces of it have been developed. Products from Autodesk, Bentley, Nemetschek and Gehry Technologies meet some of the needs of architects, engineers, contractors and facility managers. The most developed solutions at present involve the architects, who have been using CAD for more than 20 years to improve productivity. Engineering software is now being tied to the building information model, and programs such as Robobat are able to automatically transfer information round trip between such programs as Revit Structure.

Other programs, such as ADS (Architectural Data Systems), IES and Solibri Model Checker let designers quickly place content, analyze building performance and check the correctness of our projects. Contractors also are recognizing the need for BIM information, and some are beginning to create BIM models before and during construction. To this end, Nemetschek has Constructor, Bentley has its programmability and Innovaya and U.S. Cost are available for Revit and AutoCAD Architecture.

According to the AIA (American Institute of Architects), 34% of BIM users now claim to use their programs for things such as cost estimation and analysis. Will there be one total BIM solution? I doubt it. I believe that the AEC/FM industry will always have room for specific software players, with the major developers creating the core programs. Below I discuss some of the software that I think is filling the BIM matrix. The first group of software represents the core technologies for basic model-building solutions.


Autodesk has several software families. The general-purpose Revit Series—Revit Architecture, Revit Structure, Revit MEP and AutoCAD Revit Architecture Suite—use purpose-built technology, are fully BIM capable and incorporate the latest technology available. These programs have achieved a 185,000 installed user base in four years. Autodesk AutoCAD Architecture (formally called ADT) and AutoCAD MEP are highly productive programs for AutoCAD-based, architecture-specific solutions. They have the largest installed architectural user base. Autodesk Civil 3D and Autodesk FMDesktop (not really BIM software, but it fits within my definition of the building information model) are highly productive, AutoCAD-based solutions for civil and facilities management.


Bentley Architecture, Bentley Structural, Bentley Building Mechanical, Bentley Civil and Bentley Facilities Manager comprise an integrated series of modules based on MicroStation V8 XM edition. They share a common interface and are fully BIM capable. Standard MicroStation has the second largest installed user base.

Gehry Technologies

Digital Project from Gehry Technologies is true parametric PLM software, based on Dassault Systemes' CATIA. It's a very comprehensive program but difficult to master. Gehry Technologies will train and/or produce building information models using this program.

Nemetschek North America

Nemetschek North America's Vectorworks Architect is a budget-priced but fully capable CAD system with some BIM capability. The company also recently bought Archicad (the oldest BIM software), Constructor and Estimator from Graphisoft. Archicad has excellent capability and the smallest installed user base. Constructor and Estimator are gaining traction in the construction industry for construction planning, scheduling and estimating.

The next group of software represents the adjacent solutions—software that assists the core technologies in completing the building information model.

ADS—Architectural Data Systems

ADSymphony is an excellent and unique application that automatically integrates 3D content from manufacturers into your AutoCAD, AutoCAD Architecture or Revit projects. Best of all, it's free for one named user and available at a minimal cost for additional users (several users in the same office can access the system for free, but not at the same time). To use ADSymphony with CAD, you simply install ADSymphony on your desktop. Then use AutoCAD, AutoCAD Architecture or Revit as you would normally, placing generic content (such as doors and windows) into your project (figure 1). Using the live interface with the ADS online database, you can select the manufacturer's catalog and content and your generic content is changed to manufacturer's content. At that point in AutoCAD Architecture, for example, the specs are automatically created, the schedules are made and the sizes of the windows are changed automatically. In AutoCAD Architecture, you must change the type and shape of the windows yourself (the sizes and attributes will be correct, but a double-hung window won't change automatically to a hopper style).

Figure 1. ADSymphony is a free application that automatically creates specifications, schedules and inserts manufacturer content into Revit virtual models.
Figure 1. ADSymphony is a free application that automatically creates specifications, schedules and inserts manufacturer content into Revit virtual models.

In Revit Architecture, everything is automatic—the content changes to the actual manufacturer's content and it creates the schedule and specs. Currently, the library has more than 900 product catalogs, complete with 3D content, and more is being created all the time. With ADSymphony, you can even search for LEED (Leadership in Energy and Environmental Design) products within the ADS search engine. This program is a must-have add-on for any architect looking for a competitive advantage. I highly recommended it.

IES <Virtual Environment>

With IES <Virtual Environment>, you can design a virtual building knowing exactly how it will perform and operate after it is built. This program is a unique, integrated system for building performance assessment. IES VE is composed of analysis modules that evaluate most building-performance properties. Some of the available IES tools are:

Thermal-analysis tools:

  • 1. ApacheCalc provides heat loss and heat gain calculations based on the CIBSE (Chartered Institution of Building Services Engineers) guide.
  • 2. ApacheLoads calculates design heating and cooling loads based on the ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) heat-balance methods.
  • 3. ApacheSim is a dynamic thermal-simulation application that can perform carbon emissions calculations as well.
  • 4. ApacheHVAC simulates HVAC plant and control systems.
  • 5. MacroFlo enables users to simulate natural ventilation and mixed-mode systems.

Lighting-analysis tools:

  • 1. RadianceIES is a detailed 3D simulation tool designed to predict daylight and electric light levels and the appearance of a space before construction (figure 2).
  • 2. FlucsPro calculates the number of luminaires required in a room and analyzes light levels for defined lighting schemes.
  • 3. FlucsDL performs lighting-design calculations to determine the day lighting levels in a room. It allows users to perform point-by-point lighting analyses to obtain light-level values in a room.
  • 4. LightPro allows users to place luminaires anywhere in a room for subsequent analysis using FlucsPro or detailed simulation using RadianceIES.
Figure 2. IES's RadianceIES is a powerful lighting-simulation program that enables architects, engineers and lighting specialists to predict the light levels and appearance of a space before construction.
Figure 2. IES's RadianceIES is a powerful lighting-simulation program that enables architects, engineers and lighting specialists to predict the light levels and appearance of a space before construction.

Solar-analysis tools:

  • 1. SunCast generates visual, graphical and numerical information that can be used to explain how the sun affects the building interiors and exterior as well as the site itself.

Evacuation- and people movement–analysis tools:

  • 1. Simulex enables users to simulate the evacuation of a building and evaluate alternative escape routes.
  • 2. Lisi lets users design and simulate elevator options.

Solibri Model Checker

I've written about this product before, but because it's so important for the building information model, I must mention it again. Think of Solibri Model Checker as a spell checker for virtual models. The program analyzes building models for integrity, quality and physical security. It checks for potential flaws and weaknesses in the design, highlights clashing components and determines whether the model complies with building codes and an organization's own best practices. Users can define rules to check just about anything in their BIM models. It found overlapping walls in my Revit model and checked for fire egress paths (figure 3). For anyone working with the GSA, this program is a must because the GSA has purchased it.

Figure 3. Solibri Model Checker helps you to get information from your building information model. Among its many capabilities is its ability to predict and check fire exit routes.
Figure 3. Solibri Model Checker helps you to get information from your building information model. Among its many capabilities is its ability to predict and check fire exit routes.

At a recent AEC/ST BIM panel that I chaired in Washington D.C., I was asked how long I thought it would take for the building information model to become universal. When I stated "15 years," several people laughed, stating that some firms were already using the building information model. It's true that firms are beginning to expand their use of the building information model, but I still stand by my timetable. The universe of the building information model is constantly expanding to encompass more types of information.

H. Edward Goldberg, AIA, NCARB, is a practicing licensed architect and AEC industry analyst. Ed's full-length book, Autodesk Architectural Desktop 2007: A Comprehensive Tutorial (Prentice Hall, is now available. His new Revit Building tutorial book will be available in fall 2007. Visit for more information or e-mail