An Automatic Meshing Scheme for Radiosity Calculation of Large-scale Application
可大规模应用的辐射度计算的自动网格化方法

Properly meshing a scene model is an important precondition to efficient radiosity calculation. There are basically two existing meshing strategies, subdivision method and shadow boundary calculation method. By the former method, large patches are automatically subdivided while necessary, and in the latter method, meshing is performed along the shadow boundary of the regions and the shadows in the scene are analytically pre-calculated. The problem in the former strategy is the detail between vertices of a big patch could be missed, so the rendering quality is unable to be assured. On the other hand, the latter approach has a limitation of being primarily applied to polyhedral scenes, and its complexity of implementation and the requirement of heavy computation also prevent itself from being applied in engineering applications. In this paper, the authors present a meshing scheme, with a primary destination towards large-scale engineering applications with a property of easy implementation and high efficiency in producing high quality images. By the scheme, they first divide the energy-receiving surfaces into small elements with a desire precision and then recombine the elements according to their visibility feature to the light source within the environment. In this method, the regions in different energy distribution could be meshed by different scale. As a result, the number of patches to be calculated is greatly reduced without degrading the image quality. The implementation and the statistics from test examples show that the scheme is particularly suitable for large-scale engineering applications due to its ease of implementation and high efficiency.