Cadalyst - August 2008 - (Page 41)

aecinsight By Jerry Laiserin Modeling Technology for Building Engineers A specialized BIM workflow suits structure and building services. uch of the initial attention paid to building information modeling (BIM) technology has focused on architectural design and the architect’s workﬂow. It can be traced back to the earliest published work on the tools and methods that we now know as BIM, such as Chuck Eastman’s 1975 architectural journal article titled “Designing with Computers Instead of Drawings.” The concept then, as now, entails architects designing, documenting, and delivering their projects through internally consistent, multidimensional computer models rather than potentially inconsistent 2D paper drawings (or their digital/CAD equivalents). As the architecture profession struggles to adapt to the radically different design workflows and business processes required by computer modeling, the engineers who serve architects and architectural projects face a different set of challenges. Whether engaged in structural design or building services design (mechanical, electrical, and plumbing, or MEP), building engineers’ design and documentation workflow traditionally has differed from that of their architect colleagues. Much of building engineering work starts with information imported from architects’ design files, whether in the form of column grids for structural design or reflected ceiling plans and the like for MEP design. Building engineers then use the architectural information (primarily building geometry) as input for analysis programs (whether of structural loads, heating and cooling loads, or the like). The calculated results of these analysis programs typically are applied to the sizing of engineered compoAutodesk nents, whether www.autodesk.com structural memBentley Systems bers, heating and www.bentley.com cooling systems, Design Master Software or other building www.designmaster.biz equipment. EngiIntegrated Environmental Solutions (IES) neers then may www.iesve.com aggregate loads Tekla and size conwww.tekla.com nections such as U.S. Department of Energy structural joints www.eere.energy.gov/buildings/energyplus and MEP distribuAugust 2008 cadalyst www.cadalyst.com M Figure 1. MEP analysis techniques such as computational fluid dynamics can be applied to highly sophisticated tasks, such as calculating airflows across a building atrium, within a BIM workflow or independently by tools such as IES Virtual Environment. (Courtesy of IES) tion systems, then detail the actual elements in which the discipline-specific design is implemented, such as structural framing elements, ductwork, piping, and so on. As practiced in the United States, several steps in this process might be performed by engineers working with or for construction subcontractors or fabricators. Multiple Tools, Multiple Models The notion of a single BIM modeling tool serving the needs of a building engineer, whatever discipline, simply isn’t applicable in the same way that a single modelauthoring tool can serve an architect’s BIM needs. In most instances, especially in the Autodesk and Bentley BIM model-authoring suites, the structural modeler and the MEP modeler or modelers are software tools that serve more as containers or carriers of architecture-derived information used in engineering analysis. Although the transport mechanism of, say, Autodesk Revit Structure, may represent some degree of innovation over the traditional transmission of column grids by 2D drawings, the subsequent workflow surrounding analysis, sizing of members, and so on often is unchanged or only slightly changed from traditional practice. Ironically, many engineering analysis tools were modelbased long before architects began to adopt model-based design for their own processes. 41 http://www.autodesk.com http://www.bentley.com http://www.designmaster.biz http://www.iesve.com http://www.tekla.com http://www.eere.energy.gov/buildings/energyplus http://www.cadalyst.com

Table of Contents Feed for the Digital Edition of Cadalyst - August 2008

Cadalyst - August 2008 Contents Editor's Window CAD Central Tech Trends: Rotor Bug Strikes Again Cadalyst Labs Reviews: Digital Dreams — Visualization Software: Make Your Design Visions a Reality Maple 12 — Math Software AutoLINE 2009 — Linetype Management Add-On Deep Access — Digital-Media Asset Management Software View Point: Examining the Autodesk–Bentley Agreement CAD Manager: Managing Multioffice Mayhem MCAD Modeling: Do You Need Modeling Standards? AEC Insight: Modeling Technology for Building Engineers CAD Cartoon Issue Indexes Hot Tip Harry: Better Living with Objects and Smart Entities

Cadalyst - August 2008

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