Abstract: The application of virtual reality in architecture is a very hot topic. In a walkthrough system, a user can observe the architecture in different view interactively. This paper discusses the characteristics and requirements of a real time walkthrough system. It also discusses the method of modeling and image generation for virtual environments. Meanwhile, the algorithmof object capture according to ray tracing and some convenient interactive tools are presented. The developed system produces a stereoscopic display and has a friendly user interface. Additionally, a specific application example is given based on the campus walkthrough system of Southwest JiaotongUniversity.