A survey of aging and weathering phenomena in computer graphics

Aging phenomena often play a key role in realistic rendering: excepting when the desired result is specifically a brand-new virtual object, their absence can lead to non-realistic surfaces, looking too clean and smooth. To solve these problems, artists either compose multiple textures manually, or directly modify object geometries. However, such techniques may not be suitable to obtain realistic results: aging processes are resulting from materials' composition, objects usury, weathering conditions, and a great number of other physical, biological, and chemical parameters. To create realistic images that exhibit a specific aging process, a designer has to know how this process appears and grows, in a physicochemical way. In this paper, we will propose a survey of techniques permitting to represent aging and weathering phenomena in computer graphics. We will use a classification depending on the processes involved, as aging phenomena influence all aspects of the rendered images (texture, reflection properties, and geometry). (C) 2008 Elsevier Ltd. All rights reserved.