An interactive modeling method for dynamic natural objects

The rapid evolution of computer graphics hardware and software has made it easy to construct three dimensional (3D) virtual environments with real-time functionality and more reality. For example, a few years ago most virtual environments consisted of only static objects such as buildings and mountains. The latest virtual environment has both static and dynamic objects such as moving cars, flying birds and clouds. However, it is not so easy to create such a environment, because dynamic objects such as clouds and water called dynamic natural objects (DNO) change kaleidoscopically from time to time. It takes users more time and effort to create these DNOs and their motions by using animation modeling tools. When creating the shape and motion of DNO in their own brains, the users should be skilled at how to use the modeler. Therefore, we propose a new interactive modeling method to easily make DNOs in the virtual environment. The particle system is one of the most popular methods to represent such objects. This system represents DNOs as a set of points. In our method, we classify a modeling process into three stages: particle generation, particle control and particle animation. Moreover, we classify these stages to some attributes, and we give an attribute to some visualized nodes for modeling rules. Each node has some rules which decide the shape or motion of DNOs. Users create a hierarchical tree to combine these nodes. The particle animation is replayed according to its tree structure. This paper proposes a new interactive modeling method introduced into firework modeling as an example of DNOs and its simulation system, describing processes to create fireworks using this method.