Citywalk: a second generation walkthrough system

The architectural framework of an advanced virtual walkthrough environment is described and placed in perspective with first generation systems built during the last two decades. This framework integrates support for scalable, distributed, interactive models with plug-in physical simulation to provide a large and rich environment suitable for architectural evaluation and training applications. An outlook is also given to a possible third generation of virtual environment architectures that are capable of integrating different heterogeneous walkthrough models