| Along with the rapid development of computer technology, the simulation technology more and more attention has been paid by people, especially in the field of virtual reality, In order to make the virtual scene more realistic and natural, the simulation of plant which effect the immersion and naturalness of the virtual scene will be more and more. The study of plant simulation technology can date back to the 1960s. At present, there are some research results in plant simulation aspects, but there are not having a more mature and systematic method, and the simulation of plant morphology is also relatively simple and plant diversity can not be a very good performance. Plants seemingly have complicated structure and various shapes, but actually there are similarity between the local and the global. Generally, fractal theory can be used to describe the self-similarity of plants. Currently, self-similar characteristics of the plant simulation aspects, L-system used widely. In this article, the tree has been selected as the research subject. In order to simulation more realistic, natural trees, using fractal L system of fractal theory combining DOL system simulates trees.This paper studies the structure of reality trees and designs more rich trees L grammar description based on L system by extending the character set, and proposes a geometric exponential decay rule which matches trees generative processing, and realizes the drawing of some three-dimensional trunk parts by combining graphics rendering engine OSG. And introducing distorted factor realized the natural twisted bodies of trees. In order to make the drawing trees more true and natural, we add texture to trunk parts, draw leaves and shadow leaves. In addition, the trees has been drawn were regarded as a node loads into the virtual scene, which has enhanced the realism of the virtual scene. Experimental results show that this article using the trees simulation method can not only realize trees realistic rendering, and can realize real-time rendering.This mainly includes the following:comparing and analyzing the commonly used methods in the plant simulation obtained the appropriate method in this paper, being fractal L system, and studied the fractal theory and L system theory and related methods. Analyzing the factors which affect the trees structure, such as internal factors and environmental factors. Meanwhile analyzing the real trees structure and designing the topological structure of trees and L grammar description of the topological structure. According to the biological characteristics of trees and proposed a geometric exponential decay rule which matches trees generative processing, and introducing distorted factor realized the natural twisted bodies of trees. At the same time, increasing the texture map and shadow effect etc improves the fidelity of trees. Adding trees node to the virtual scene and perfected the virtual scene in the show, increased the fidelity, which makes the rover immersive feeling. Finally, the paper given an expectation to the development of trees simulation. |
