A Fast Ambient Occlusion Method for Real-Time Plant Rendering

Global illumination effects are crucial for virtual plant rendering.Whereas real-time global illumination rendering of plants isimpractical, ambient occlusion is an efficient alternativeapproximation. A tree model with millions of triangles is common, andthe triangles can be considered as randomly distributed. Theexisting ambient occlusion methods fail to apply on such a type ofobject. In this paper, we present a new ambient occlusion methoddedicated to real time plant rendering with limited userinteraction. This method is a three-step ambient occlusioncalculation framework which is suitable for a huge number ofgeometry objects distributed randomly in space. The complexity ofthe proposed algorithm is O(n), compared to the conventionalmethods with complexities of O(n^2). Furthermore, parameters inthis method can be easily adjusted to achieve flexible ambientocclusion effects. With this ambient occlusion calculation method,we can manipulate plant models with millions of organs, as well asgeometry objects with large number of randomly distributedcomponents with affordable time, and with perceptual qualitycomparable to the previous ambient occlusion methods.