REAL TIME POLYGONAL DATA INTEGRATION OF CAD/AUGMENTED REALITY IN ARCHITECTURAL DESIGN VISUALIZATION Xiangyu Wang 1 and Phillip S. Dunston 2 ABSTRACT An integration of CAD and Augmented Reality (AR) was previously implemented in a prototype system, Augmented Reality Computer-Aided-Drawing (AR CAD). The algorithm adopted for the real-time transfer of data between CAD and the AR viewer requires downloading the 3D solid model description at the client side via networking socket codes and supports only the AR rendering of piping system models. In order to get around the limitation of a required database, a polygonal data transfer scheme is proposed for any 3D solid models generated in a standard CAD modeling package. The approach decomposes the 3D solid model as a union of many single objects, which are in turn, approximated as groups of polygons. The vertex information of each polygon of a specific single object is extracted by a procedure which can operate on top of AutoCAD ® . Such data may be used by OpenGL functions in the AR viewer for real-time virtual model rendering. KEY WORDS CAD/Augmented Reality, Virtual Reality, polygonal data, real time. INTRODUCTION Three-dimensional computer-aided design (3D CAD) and visualization has ushered in new opportunities for enhancing the design and planning functions in the architecture, engineering, and construction (AEC) industry (Griffis and Sturts 2000). Less abstract than 2D design visualization, 3D CAD modeling has emerged as the most advanced practice in design visualization practice today with the commercial accessibility of high-end graphics computing. Examples of 4D CAD modeling and planning for facilities with highly complex designs has further inspired the drive toward technology and information integration to facilitate more efficient project execution (Post 2002). The notion of exploiting Virtual Reality (VR) technology for architecture and engineering design has been gradually gaining popularity, mainly during the last decade or so, as computing advances have supported more sophisticated graphics capabilities. The typical VR applications today include 4D (3D linked with schedule) desktop PC virtual environments (VEs) (VTT 2002), safety (Hadikusumo and Rowlinson 2002), and Web-based design review and computer supported cooperative work (CSCW) (Campbell 2000). These 1 Ph.D. Candidate, Res. Asst., Purdue University, School of Civil Engrg., 550 Stadium Mall Dr., West Lafayette, IN 47907-2051; Voice: 765-409-3475; FAX: 765-494-0644; E-mail: wang0@purdue.edu. 2 Asst. Prof., Purdue University, School of Civil Engrg., 550 Stadium Mall Dr., West Lafayette, IN 47907-2051; Voice: 765-494-0640; FAX: 765-494-0644; E-mail: dunston@purdue.edu.