Game Engine Support for Terrain Rendering in Architectural Design T. Yang, B. C. Wünsche, and R. J. Lobb Graphics Group, Dept. of Computer Science, University of Auckland, Private Bag 92019, Auckland, New Zealand. Kelly.Ting.Yang@gmail.com, burkhard@cs.auckland.ac.nz, richard.lobb@canterbury.ac.nz Abstract Game engines are relatively low-cost but powerful systems for creating and exploring virtual environments, and are increasingly used in the fields of architecture and urban planning. Traditionally urban planners and landscape architects used small-scale hand-modelled terrains. However, in order to increase both realism and modelling efficiency it is preferable to use computer generated terrains obtained from remote sensing data. Unfortunately many game engines are designed to use relatively small infinitely repeating terrain blocks. In this paper we analyse how the popular Torque terrain engine, which is used by the Department of Architecture of the University of Auckland, can be modified and extended for architectural purposes. The ultimate limitations of the terrain engine are identified and the terrain engine is evaluated on its suitability for architectural design. We explain how large scale terrains can be incorporated into the engine design and we propose a way to integrate the hardware-friendly chunked level-of-detail terrain rendering algorithm into the terrain engine. Our results show that the proposed implementation makes better use of the GPU of modern graphics cards and it frees CPU load for use by other modules of an architectural design tool. Keywords: Game engine, architectural design, terrain visualization, level-of-detail 1 Introduction Over the past couple of years architecture researchers have started to embrace game engines, which are programming frameworks for the rapid development of computer games, to visualize buildings and the outside world [1,2]. Game engines are a promising architectural design tool for the following reasons [1]: • They usually employ cutting-edge computer graphics techniques, to support enjoyable real- time interactive exploration of the world. • They are usually designed for home PCs and thus they are cheap and don’t require expensive hardware devices. • On-line massive multiplayer (OMM) game engines provide a collaborative environment that is very suitable for architectural teamwork. The terrain rendering ability of game engines contributes greatly to the realism of a computer- generated virtual environment where 3D building models are embedded. The School of Architecture of the University of Auckland has been exploring the usage of game engines since 2001 [3]. Their work is based on the Torque Game Engine (TGE) [4] which has a large user community for game development and simulations. 1.1 Motivation User feedback from the School of Architecture identified the following limitations and shortcomings of the terrain engine in TGE: • The engine can load only 256×256 image files as terrain data. However, the real world terrain data exists in lots of different formats and different dimensions. Architects have to use pre- processing tools to convert the data into image files, and divide the data manually into 256×256 blocks before importing. Most of those processing tools are either expensive or not easy to use. • The TGE terrain engine only stores one terrain block. The whole world is constructed by tiling the same terrain block in all directions to infinity. Architects cannot represent a real area larger than one terrain block without repeating it. • Most architecture labs and workshops use modern rendering hardware. They want the engine to take full advantage of the hardware