Research On Dynamic Simulation Of Trees Swaying Based On Iterated Function System

With the improvement of computer performance and the development of computergraphics, the research of virtual plants, especially the modeling of the natural scenery hasbeen applied to many areas, such as the gaming industry, animation and advertising and so on.The theory is based on plant partly characterized in overall self-similarity-based,according tothe local feature and the affine transformation function, the plant modeling can be built,through the strong ability of the computer iteration. With the development of computersimulation technology, the static simulation of plants has become unable to meet therequirements of the real-world applications, and the simulation of tree swaying becomes a hotissue of research. In many researches, the trees simulation, especially dynamic simulation ofthe tree is particularly important. This thesis focuses on the simulation of fractal trees swayingin the wind field.Firstly, according to the methods of plant modeling which han been demonstrated in thereference, this thesis analyzes and compares the advantages and disadvantages of variousmodeling methods. Then this thesis uses the iterative function system based on the Gaussnoise factor to build the three-dimensional modeling of trees. By adding random valuesgenerated based on the Gaussian random function, this thesis adds these random values to theattributes of the rotation angle of the branches and leaves, the trees forms are randomized andthe simulation results are more real. By employing the texture mapping and rendering, and theAlpha test, the trees modeling is built, and it can enhance the authenticity and fidelity of thetrees modeling.Secondly, this thesis builds the natural state mathematical model of the virtual wind byadding random noise produced by the Perlin noise function value. In the virtual wind field,according to the application of dynamic knowledge, the offset form of single branch isobtained by anayzing the stress of branches,and then simulates the effect of the rotation of thewhole of the branches in the wind field; And, based on the stress analysis of the leaves, thesystem simulations the leaves around the three-dimensional coordinate system axis deflection movement in the wind field. Eventually, this thesis can simulate the effect of the completemodel of trees swaying in the wind field.Finally, by the addition of three-dimensional terrain, sky, sound module to complete thethree-dimensional rendering of the scene, and through the fog effect,the virtual scene fidelityis increased, and the dynamic effects of the tree’s simulation is made more real.The trees swaying simulation system is developed through using VC++6.0and OpenGraphics Library. The method is able to generate realistic, natural three-dimensionalmorphological features of trees, and realistic simulation of the trees swaying movement underdifferent wind size. The experimental results show that the method is effective, and it cansimulate the effect of the trees swaying.