L System Fractal Tree Realistic Structure And The Tree Swaying In The Wind

Modeling irregular fuzzy objects is one of the most challenging problems in computer graphics. The development of modeling fuzzy objects made virtual scenes more actual. Various plants spread all over the world. As a branch of modeling for irregular object, plants simulation attracts many scientists' attention. Plants have complicated three-dimensional structure, and many factors affect the growth of plants. The simulation for shape and movement of plants is very difficult and challenging consequently.Firstly, the expression mechanism of simulating plant by applying L system was researched on the basis the fractal character of plant shape. Those usual forms of L system, such as DOL system, stochastic L system, parametric L system and their expression character were analyzed respectively, which prepared a solid base for the application of L system method to simulating plant.Secondly, simulation for bending branches was improved .The method of mechanism model of elastic rod was applied in the algorithm of simulation for bending branches based on L system. Through analyzing tropism and gravity, our algorithm simulated bending shape of branches as a result of tropism and gravity.The dynamic model of trees was studied through analyzing mechanism model of branches; The flurry force, axial damping force and restoration force were expressed .These forces mentioned before made up of a more perfect wind field. The approximate numeration was used to calculate the movement of branches based on dynamic formula, then the movement of branches was simulated.Finally, the improved algorithm about simulation of bending branches and the algorithm about movement of branches based on improved wind field were implemented. L system code of poplar were designed and combined with improved algrithm about simulation of bending branches. The three dimensional model of poplar was achieved. The improved wind field was acted on osier modeling, the movement of trees effected by more perfect wind field was simulated through VC++ and OpenGL.