In this paper, we describe the creation of a photorealistic digital 3D representation of a real world city and its subsequent publication as an open and collaborative 3D virtual world on the web using an open source software platform. We present the guidelines and conventions used in the collaborative development process of the model. We report the design and implementation of the web user interface of the model that exploits on dynamic on demand (un)loading of assets during navigation to reduce memory consumption on user device. We demonstrate the extensibility of the model with example applications. We report an empirical performance evaluation of the web user interface in terms of download latencies and memory consumption, and frame rate achieved with three different types of user devices during navigation. We identify a rendering bottleneck in the current implementation and present a candidate solution for fixing it.
['Toni Alatalo', 'Timo Koskela', 'Matti Pouke', 'Paula Alavesa', 'Timo Ojala']
VirtualOulu: collaborative, immersive and extensible 3D city model on the web