Virtual reality (VR) technology can be used to simulate environments of historical sites in virtual spaces. In fact, many VR reproductions of historical sites have already been studied and developed. For users, the quality of the visual experience largely determines the authenticity of a VR space. However, when developing a VR space, it is difficult and time-consuming to significantly improve visual quality while maintaining real-time rendering speed, which is the primary requirement of an effective user interface. For this reason, there have been few genuinely photorealistic VR spaces created for historical sites. However, this has begun to change due to the arrival of next-generation three-dimensional (3D) game engines. In this paper, we report on our recent development of photorealistic VR spaces for historical Kyoto sites created using the UDK 3D Game Engine. Specifically, we describe our VR reproduction of Reizei-ke, which consists of the Japanese court noble residence (kuge-yashiki), and Funehoko-cho, which is an important site for Japans Gion Festival. Through the fabrication of these VR spaces, we could also extract a workflow that allows us to realize photorealistic and read-time VR contents of other cultural assets based on the abovementioned next-generation 3D game engine.
