| Trees play a very important role in the natural scenery of landscape. Over a long time, more work have been focused on modeling the shape and the growth of the trees. Although there are many successful work in Film and Television, Advertising, Games, Virtual Reality, and other field, texture mapping is still the most common technique utilized today in creating trees. Few people have been conducting research work in simulating the physical motion of trees, and allow them going naturally with wind. Therefore, as an attempt, dynamic simulation of the tree in the wind was studied.Firstly, based on a stochastic method and aerodynamics analysis, we proposed a wind model about wind speed and wind force .and make the detailed presentation about the noise technique. Noise plays an important role in tree's dynamic simulation. Using noise technique can make the dynamic effects of the tree's simulation more real.Secondly, using L-system established tree model. In the process of modeling, getting two-way linked list to store control point data of the tree model .Then using the depth-first traversal method to traverse the two-way linked list. On the basis of acquisition of data for each branch, to use the method of solving differential equations and calculating the rotation angle of the line to analyzed the movement of branches.Finally, the leaf's movement is analyzed. Including leaf's movement with the branch swaying and leaf's falling. When leaf no falling, the leaf is moving around the movement of the branch. Meanwhile, the leaf's face is rotating around the leaf's petiole. When leaf falling, the movement is solving by the classical Newton's Mechanics.Based on above research results, the system of tree swaying in the wind has been developed using VC++6.0 and OpenGL. Experiments show that the method is effective, and the simulation result is realistic. |
