Compact and progressive plant models for streaming in networked virtual environments

Just as in the real world, plants are important objects in virtual worlds for creating pleasant and realistic environments, especially those involving natural scenes. As such, much effort has been made in realistic modeling of plants. As the trend moves towards networked and distributed virtual environments, however, the current models are inadequate as they are not designed for progressive transmissions. In this article, we fill in this gap by proposing a progressive representation for plants based on generalized cylinders. We model the shape and thickness of branches in a plant as Bézier curves, group the curves according to the similarity, and differentially code the curves to represent the plant in a compact and progressive manner. To facilitate the transmission of the plants, we quantify the visual contribution of each branch and use this weight in packet scheduling. We show the efficiency of our representations and the effectiveness of our packet scheduler through experiments over a wide area network.