ISSN : 1796-203X
Volume : 2    Issue : 4    Date : June 2007

A Clustering Framework for Real-time Rendering of Tree Foliage
Cristina Rebollo, Inmaculada Remolar, Miguel Chover, Jesús Gumbau, and Oscar Ripollés
Page(s): 57-67
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Real-time rendering of vegetation is currently a problem in need of a solution. The lack of plants and
trees reduces the realism of outdoor scenes. The large number of polygons that form this kind of
objects implies that current hardware cannot achieve interactive rendering of outdoor scenes. This
paper deals with this problem and it presents a multiresolution scheme that allows us to represent
the whole geometry of the trees and forests using both uniform and variable levels of detail. The
method presented here models the trees using two multiresolution approaches, due to the different
characteristics of the geometry that forms them. The trunk is modelled with a solution oriented
towards representing continuous meshes, and the foliage is modelled with the multiresolution
model Level of Detail Foliage, presented in a previous work. Both of them have been designed to
take advantage of the graphics hardware by adapting the data structures and the rendering
algorithms to make the visualisation time efficient. The main characteristic of Level of Detail Foliage
is the fact that it classifies the leaves that form the foliage in independent clusters in order to
improve the visualisation time. In this paper, it has been efficiently implemented and extended to
allow us to change the level of detail in a variable manner, by adapting the resolution of the crown of
the tree to certain criteria determined by the application.

Index Terms
real-time rendering, clustering of leaves, tree representation, multiresolution, hardware graphics,
level of detail.