Research And Development On Highway Route CAD System

The computer-aided design (CAD) system is regarded as one of the most important achievement of the 20th century in the modern technology, which affects today's industry and all the engineering fields greatly, and brings enormous social and economic benefits to all trades. Among the realm of engineering investigation, the traditional manual methods are being replaced by the CAD techniques gradually. The most remarkable character of the computer is that it can process information and data accurately and quickly. The CAD technique combines this advantage of the computer with man's creativity and the capacity of reasoning and judging effectively. Thus, it can provide engineering investigation design with ideal means and methods. As a consequence, a very much wider range of applications becomes suitable for computer-aided design and there seems little doubt that the engineering will be able to take increasing advantage of this valuable design tool in the future. This paper focuses on the research and development on highway route CAD system, analyzes the process and the method of highway alignment design, expounds design theory and calculating method on plane section, longitudinal section and cross section, and introduces the solution to some concrete problem occurring during the highway route design, such as oval curve's calculating method, the horizontal curve's super elevation transition, co ordinate's transformation and calculation, and alignment's perspective drawing. Considering all these respects, the practical highway route CAD system have been completed successfully.The research of computer algorithm is the essence of the programming design. Therefore, the main concern of this paper is the mathematical model and the computer algorithm of the various geometry elements. As for the problem of computer software engineering, such as system structure, programming skill, data structure and data transmission, nothing much is mentioned in this thesis. The guiding ideology of programming can realize the expected calculating and drawing function. From the angle of software engineering, there is still much room for improvement.At present, the plane design model we adopted is based on traverse method, a traditional way, which is still in practice in the majority of the domestic design departments.Traverse method is simple and easy to master by the highway designer. The program uses the most extensive PC and window's operation system as it's system platform, and the programming language is based on Visual Basic 6.0, the drawing and table of the design is accomplished under the environment of the AutoCAD R14. There are about 11,000 rows source program code compiled during the course of program development, and these source codes have been debugged and translated by system. The program can accomplish the major design calculation of the Plane section, longitudinal section, cross section of various class highways; it also can draw various kind of design drawing and table, as well as the calculation of earth and stone volume. Through test, the system proves to be practical.