Cadalyst - June 2008 - (Page 42)

aecinsight By Jerry Laiserin Data Collection in AEC Linking the real world to the virtual world. teady increases in the power, performance, and sophistication of computer hardware and software enable AEC project teams to maintain their design, documentation, and delivery processes entirely in the digital realm. For new buildings, freestanding on virgin sites, such digital or virtual project processes might provide all the information needed for real-world construction. However, any project that involves repairs, alterations, or additions to existing buildings or that requires inﬁll between or among existing buildings also requires capturing information about those buildings and bringing that captured data into the digital realm. Thus, AEC data collection closes a loop in the project process of the following: u capture of data about existing or as-found physical conditions u transformation of captured data to digital models u digital modeling of new work integrated with a digital model of existing conditions u construction of new work within the existing work, based on the integrated digital model u capture of data about as-built physical conditions Although several techniques are available for digital data collection, all have significant advantages over manual measuring methAsbuilt Services ods in terms of higher www.asbuiltservices.com speed, greater accuracy, Coast 2 Coast Surveys and lower cost. www.c2csurveys.com S Figure 1. Laser Models, an innovation of Quantapoint, provide highly readable detail of existing conditions. Such laser-scanned data, as in this isometric view of stairs in a museum (ceiling and walls clipped for easier viewing), can be used directly in 3D CAD/ BIM software for design purposes as well as to generate 2D drawings. (Image courtesy of Quantapoint) Construction Systems Associates www.csaatl.com Line of Sight The two most popular techniques for AEC data collection for existing buildings are photogrammetry and laser scanning. According to Wikipedia, photogrammetry is a process whereby ª threedimensional coordinates of points on an object are determined by measurements made in two or more photographic images taken from different positions. Common points are identified on each image. A line of sight (or ray) can be con- Eos Systems www.photomodeler.com Existing Conditions www.existingconditions.com Frazier Associates www.frazierassociates.com GiveMePower www.givemepower.com Leica Geosystems www.leica-geosystems.com structed from the camera location to the point on the object. It is the intersection of these rays (triangulation) that determines the three-dimensional location of the point.º Although photogrammetry dates back to the nineteenthcentury origins of film photography, modern digital cameras and software such as Eos Systems' PhotoModeler vastly simplify and accelerate the process of photographing, measuring, and modeling 3D points on or in an existing building. Designers who frequently need to capture existing conditions data and measurements might opt to purchase photogrammetry equipment and software. Occasional users could find that it' s more efficient and cost effective to call on experts who provide photogrammetry-based building models as a service, especially on projects that entail highly specialized historic preservation work. Frazier Associates of Staunton, Virginia, is an architectural firm that has developed in-house expertise in photo documentation of historic structures, which the firm provides on its own projects as well as a service to clients across the United States. Frazier Associates also provides rectified photogrammetry, a further specialization that delivers scalable images. Quantapoint www.quantapoint.com Measure for Measure Many architectural projects, such as tenant fit-out of office or retail space, require only floor plans of as-built conditions. Companies such as GiveMePower focus exclusively on these needs, which some observers have labeled BSIM (building surveying information management). Demand for BSIM is growing so rapidly (65% per year) that GiveMewww.cadalyst.com cadalyst June 2008 Trimble www.trimble.com Vertical Access www.vertical-access.com 42 http://www.asbuiltservices.com http://www.c2csurveys.com http://www.csaatl.com http://www.photomodeler.com http://www.existingconditions.com http://www.frazierassociates.com http://www.givemepower.com http://www.leica-geosystems.com http://www.quantapoint.com http://www.trimble.com http://www.vertical-access.com http://www.cadalyst.com

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

Cadalyst - June 2008 Contents Editor's Window CAD Central Tech Trends: Community Building in Progress A Quarter Century of Cadalyst Tracking a CAD Giant The Highs and Lows of CAD Hardware Industry Insights — Looking Ahead Cadalyst Lab Reviews: HP xw4600 Workstation with LP3065 30” LCD Monitor NVIDIA Quadro FX 3700 — Graphics Card LaCie 324 — LCD Monitor CAD Manager: Making Standards Stick MCAD Modeling: Rational vs. Irrational Decisions AEC Insight: Data Collection in AEC CAD Cartoon Issue Indexes Hot Tip Harry: Just a Few CAD Renovations

Cadalyst - June 2008

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