Modeling 3D Tree Based On Convolution Surfaces

Tree model is essential for 3D scene modeling. While the structure of tree is complex to cars or buildings which are convinced for modeling. How to use computer language fast, simple and realistic to draw a tree, has been the subject of computer graphics research workers. After years of research, there are many ways modeled trees. However the function of modeling tree can be split into two ways. The first one is Parametric Surfaces. The rest is Implicit Surfaces. General tree modeling technique uses one kind of surface modeling techniques. The advantage of Parametric Surfaces is easy to control and render. And it costs little time to compute. The disadvantage of Parametric Surfaces is discontinuities which would cause not smooth. The disadvantage of Implicit Surfaces is not conductive to render and be controlled. Although the implicit surface is difficult to render, but can solve the problem of parametric surface junction discontinuity. Implicit surface and parametric surface to form a good complement.This paper presents a new method for rendering three-dimensional trees.It combines two surface modeling techniques to model trees. First, we can divide tree into trunk, branch and leaf. Trunk is deep and resonant which can reflect the specific characteristics of the trees. Branches and leaves tend to be more dense, more quantity, the leaves will block the branches of trees. So when we observe trees, we would care about the branches and trunk. So we can use implicit surfaces to render trunk which can solve the discontinuity at the junction. We can observe the detail of trunk. We can use parametric surfaces to render branch with small computing which can form a picture of lots of branch and leafs. In order to join the trunk and branch, we put forward a piecewise L system.Taking advantage of piecewise L system and using implicit surface to modeling tree trunk, parametric surface to modeling tree branch and leaf. At last using GLSL to render three-dimensional tree. And we modify rendering algorithm based on CPU. It improved rendering speed, enhanced graphical fidelity.Experiment shows that the proposed method can modeling complete 3D tree with satisfied visual effect.