Software strategy: BIM comparison: how does BIM software stack up with the 3D model concept?

CADalyst, Jan, 2005 by H. Edward Goldberg

* Autodesk Architectural Desktop 2005

Autodesk Architectural Desktop is an object-based BIM solution based on AutoCAD. Any improvements or updates to AutoCAD are reflected in Architectural Desktop. This solution uses specialized programming and routines to make AutoCAD perform as a BIM modeler (figure 1). It's a unidirectional solution that saves all information in separate DWG drawing files. Each file often contains information on disparate information such as doors and walls.

[FIGURE 1 OMITTED]

These files are then linked by a programmed xref system called the Project Navigator so the program can interact with them. Architectural Desktop is unidirectional in that any change in the model is expressed in all views, but not all views can change the model. In most cases, Architectural Desktop's documents must be saved and views refreshed to update and coordinate all of its documents.

This five-year-old solution in its fifth version. It's the most widely distributed BIM software, due in great part to the large installed AutoCAD user base. Architectural Desktop is very capable and relies heavily on the automation of entity creation. It's very sophisticated software, so new users may have some initial difficulty, but in the hands of an experienced operator, it's very productive and capable of handling the biggest projects. Because it's basically enhanced AutoCAD, using the native DWG format, it's especially capable during the construction document phase. Because Architectural Desktop is very popular, several third-party books are available, and it's taught in many universities and community colleges. More third-party plug-ins are available for Architectural Desktop than for any of the other BIM solutions.

* Bentley Architecture

Bentley Architecture is the architectural application within Bentley's multidisciplinary suite of solutions. It's an object-oriented product, and like its companions for structural and building systems engineering, it's based on the MicroStation platform. Because MicroStation has the second largest number of installed seats, there is a large pool of operators from which to draw. MicroStation or AutoCAD operators can easily become proficient with Bentley Architecture, and Bentley offers full DWG support to integrate with AutoCAD and Architectural Desktop users on mixed-platform projects.

Bentley Architecture has been used by leading firms on many large and inspiring architectural projects around the world. For example, Bentley's architectural and engineering solutions are currently being used to construct a full multidisciplinary model of the Pentagon, the largest office building in the world.

Bentley Architecture includes full top-quality rendering and animation from within its user interface (figure 2, p. 53) and also provides capabilities for modeling, visualization, reporting, schedules, cost and program analysis, bidirectional integration with engineering analysis applications, schedule simulation and 4D design. It also offers a capability called 2D/3D choice, which allows users to work in either the 3D model or 2D drawing views--or in both at the same time--while keeping all drawings and the models in sync.