Schilling et al. / J Zhejiang Univ SCIENCE A 2006 7(9):1482-1491 1482 CAD-VR geometry and meta data synchronization for design review applications * SCHILLING Arne †1 , KIM Seokryul 2 , WEISSMANN Daniel 3 , TANG Ziying 1 , CHOI Sangsu 2 ( 1 Fraunhofer Institute for Computer Graphics (IGD), Darmstadt 64283, Germany) ( 2 Institute for Graphic Interfaces (IGI), Seoul 120-750, Korea) ( 3 Computer Graphics Center (ZGDV), Rostock 18059, Germany) † E-mail: arne.schilling@igd.fhg.de Received Feb. 28, 2006; revision accepted May 3, 2006 Abstract: In this paper we present the MEMPHIS middleware framework for the integration of CAD geometries and assemblies with derived Virtual Reality (VR) models and its specific meta data and attributes. The goal of this work is to connect real time VR applications, especially for the Design Review, with enterprise software storing and managing CAD models (Product Data Man- agement—PDM). The preparation of VR models requires expert knowledge, is time consuming, and includes selection of required CAD data, tessellation, healing of unwanted gaps, applying materials and textures, and special surface and light effects. During the Design Review process, decisions are made concerning the choice of materials and surface forms. While materials can be switched directly on the VR model, the modification of part geometries must be made on the CAD model. Our system synchronizes modi- fications of the original CAD geometries and of attributes that are relevant for the realistic rendering using the PLM Services standard. Thus, repeated work for the VR preparation can be avoided. Key words: Virtual Reality (VR), CAD, Product Data Management (PDM), Geometry conversion doi:10.1631/jzus.2006.A1482 Document code: A CLC number: TP202 INTRODUCTION The first phases of the product life cycle are almost completely digitalized nowadays. Single parts or complete product models are modeled with 3D CAD solutions. Assembling single parts to digital mockups (DMUs) is important for checking the de- pendencies between the parts and detecting conflicts. Due to their complexity, such data is managed in specialized Product Data Management (PDM) sys- tems. They gained an increasing importance in many industries during the last decade (Qiao and McLean, 2004). Currently they are extended to support more phases of the product lifecycle up to production and shop floor planning and are correspondingly called Product Lifecycle Management (PLM) systems (Nowacki and von Lukas, 2003). In industries concerning highly complex end consumer products, it is crucial not only to design the geometrical shape of the product parts using CAD workstations, but also to be able to review the interior and exterior before assembling the first prototype (Hur et al., 2006). Our aim is to support new 3D technologies for the Design Review process that are based on a high resolution real time 3D representation using realistic surface simulation (compare Fig.1). In comparison to desktop applications, such Virtual Reality (VR) systems using Head Mounted Displays and high resolution 3D displays can lead to a much better spatial understanding. Such displays are not able to process CAD data directly but need models composed of triangle sets (Graf et al., 2002). Usually PDM systems cannot manage meta data related to the VR files (e.g. light settings, materials, textures, and behaviors). They lack functionalities to Journal of Zhejiang University SCIENCE A ISSN 1009-3095 (Print); ISSN 1862-1775 (Online) www.zju.edu.cn/jzus; www.springerlink.com E-mail: jzus@zju.edu.cn * Project supported by the Korean Ministry of Information and Communication (MIC)