Hardware-Oriented Visualisation of Trees

Real-time rendering of vegetation is currently a problem in need of a solution. The large number of polygons that form this kind of objects means that current hardware cannot achieve interactive rendering of outdoor scenes. This paper deals with the problem and it presents a multiresolution scheme that allows us to represent the whole geometry of the trees using both uniform and variable levels of detail. The method presented here models the trees using two multiresolution models. This is due to the different characteristics of the geometry that forms them. The trunk is modelled by LodStrips, a model oriented towards representing continuous meshes, and the foliage is modelled by the multiresolution model Level of Detail Foliage, presented in a previous work. In this paper, it has been efficiently implemented and extended to allow us to change the level of detail in a variable way, by adapting the resolution of this part of the tree to certain criteria determined by the application. Both of them have been designed to be hardware-oriented. They take advantage of the graphics hardware by adapting the data structures and the rendering algorithms to make the visualisation time efficient. Finally, the multiresolution scheme presented in this paper is compared with the only work that has appeared up to now that uses the same technique.