Foliage Simplification Based on Multi-Viewpoints for Efficient Rendering

Vegetation is an essential component of the outdoor scene in the fields of virtual environment and computer game. The foliage models consisting of a great number of complex structures make real-time visualization impossible. In this paper, a novel viewpoint-driven foliage simplification framework is proposed for efficiently rendering virtual plants in polygonal models. Before the collapsing step, complex leaf models are reshaped as quadrilaterals and then separated into clouds of cells for rapidly finding the best leaf pair. Unlike the geometric foliage simplification approaches, we introduce an information-theoretic tool, mutual information to measure the leaf visibility and the leaf-collapse error from multi-viewpoints. The viewpoint-dependent foliage simplification algorithm produces foliage level of detail (LoD) models close to the original ones in terms of visual and geometric criteria. Our approach is appropriate for applications which require exact geometry tolerance but also high visual quality.