The Key Technology Of Walkthrough In Virtual Environment

Involving the plant generation technology into virtual environment, which may integrate the artificial environment and natural environment, and thus develop a realistic virtual world. At the same time, the technology of real time walkthrough in virtual environment will contribute a lot convenience to CAD in architecture, environment designing, city layout. and provide a good solution for digital city and virtual community.In this thesis, our research work mainly focuses on the following four aspects:1, Studying and perfecting the generation algorithms of plant modeling,building three-dimensional plant modelOn the basis of studying current algorithms of plant modeling, combining Iterated Function System and L-System, we brought forward the random binary three-dimensional recursive model. The generation and render process of the tree could be simplified to: draw the branches from the root, then the branches are split into left branch and right branch. The process of drawing branch would be divided into many steps, we can draw the leaves in the last step.2, Study ing and perfect ing the algorithms of walkthrough in virtual environment, accelerating the walkthrough in virtual environmentIn this paper, we evaluate the advantage and disadvantage of the current algorithms of walkthrough in virtual environment by the rendering process of photorealistic graphics, and then brought forward a new algorithms of real time walkthrough based on the integrated polygon and texture. The algorithms transform polygon and texture into each other, and generate fade polygon by geometrical interpolation in the projection of texture, which would realize smooth transition between polygon and texture. Furthermore, it combine the idea of Level Of Detail of polygon and texture.3. Designing and deveIoping " the Interactive Designing and Walkthrough System of Virtual Forest"Making use of VRML and VC++, we developed an interactive designing and walkthrough system of virtual forest. In the system, the application of VRML assured the real time interaction and walkthrough on the Internet. Considering the data quantity, a thought of replacing the plant model by plant image has been adopted in the system, which may provide more realistic natural scene for the user.4. Designing and developing "the Interactive Generating and Walkthrough System of Three-dimensional Tree" -OpenGL TreeMaking use of the close interface of OpenGL and C++ Builder, we developed an interactive generation and walkthrough system of three-dimensional tree -OpenGL Tree. The system realize the random binary three-dimensional recursive model, and generate three-dimensional tree model to compose natural scene; in addition, it apply the accelerate algorithms based on the integrated polygon and texture, and realize interactive walkthrough in virtual environment.At last, we summarize the work of this thesis and discuss the potential research topics in the future.