3D Visualization Of Trunk And Branch Model Of Pear Tree

Virtual Plant is a new field of research with the rapid development of information technology and computer technology,and it is interdisciplinary subject based on computer graphics, botany, mathematics, and virtual reality technology。Virtual plant modeling is computer simulation of plant growth process in three-dimensional space applying virtual reality technology studying on the plant morphology. Simulating the whole group of whole life cycle of plant in a very short period of time with the technology make us grow plant in virtual environment quickly ,which save time and manpower also cost. It provides a fast and intuitive method of scientific research. L-system has become an important tool of virtual plant modeling because of the powerful ability of simulating morphological structure of real plant. Compared with other methods, L system can simulate different sorts of plant, whose formal language approach have solid mathematical theory.Modeling virtual branches of fruit trees has significant impact on studying the virtual fruit trees'growth, whose expression is a major research of virtual modeling system. From the latter half of past century, the researchers have constructed many models of tree branches, but they don't in-depth study the structure of different fruit tree. The visualization method of fruit tree branches that combines morphological information and parametric L-system is presented. Basing on studying on the structures of pear tree, morphological characteristics ,characteristics of ecological change and so on are extracted ,then L-System model of pear tree including the thickness of the branches, bifurcation angle etc. are established, and geometric information of plant growth are transformed into intuitive graphical information and visual output through 3D modeling algorithm basing on OpenGL. Finally, we simulate basic forms of common pear tree (natural open center type, sparse layer of the main crown shape, small crown layer shape), which lays a foundation for developing the computer simulation system of pruning pear tree. The major work is summarized below:1. Studying method of virtual fruit tree basing on L-SystemMake in-depth research of L-System's theory and algorithm basing on growth model and pruning measures of pear. Then determine the overall framework of the morphological description of pear. Finally, extract L-system rule of pear and establish of virtual model of pear branches.2. 3D visualization output of rule-based modelIn Windows operating system, render model of L-system rules such as view transformation, display scaling, illumination settings and so on with the development environment basing on Visual C++ and OpenGL graphics library. Finally, complete visualization output of model.