A semi-automatic generation method for visually-plausible virtual clouds

Cloud is one of the most important atmospheric effects in computer graphics applications, and there have been lots of research results on it. Although they have mainly focused on the modeling and rendering of more realistic clouds, nowadays flight simulation games or even full-scale flight simulators often need a quantity of visually plausible clouds rather than realistic ones. Furthermore, we also need to save graphics designer's efforts, especially for small production companies. Contrary to the previous works, we aimed at the mass production of clouds, and represent a new method for modeling various kinds of visually plausible clouds with as little effort as possible. These clouds are displayed in real time with low computing power consumption. Based on the hierarchical particles, our system starts from locating relatively large spherical particles in the space. Using these seed particles, our system automatically generates descendant particles to represent details of the clouds. In this way, the visually plausible clouds can be generated with much less effort, while the designer may build up specifically shaped clouds through controlling the seed particle locations. The particle hierarchy also enables us to naturally implement level-of-detail effects on the cloud rendering. In the final rendering stage, our system renders each particle with alpha-blended billboards to achieve fast real-time processing.