Research And Implementation Of Ray Tracing Technology In 3D-City Environment

With the surveying technology development, it is easier to rapidly obtain the spatial information; and much easier to rapidly build the three-dimensional geographical environment with the well used virtual reality technology.At present,the most used applicatios in 3D-City environment are inquiry,roam and so on,GIS does not fully reflect its key role in various industries.So,the paper starts the research work of Ray Tracing model in the 3D- Scene. The paper aims to study the spatial layout characteristics of urban mass buildings, Ray Tracing acceleration algorithm, so in the case of massive spatial data,the calculated speed is more quickly with this model. After complished the research and the algorithm of Ray Tracing,the paper applys the model in mobile communications to carry out signal prediction.The following studies were made in this paper:(1) It studied the organization of 3D-City data. It studied the mechanism of spatial data index and the relationship between the spatial layout characteristics and nature, culture, the paper proposes a data structures based on rule-based grid and CELL index.(2) It studied the Ray Tracing acceleration algorithm.After organized the urban mass data efficiently,study the partition method,3D-2D method and multi-mirror acceleration method. Compare the advantages and disadvantages of each acceleration algorithm,find a suitable method of Ray Tracing acceleration algorithm.(3) It achived algorithm with program language and conduct the comparative analysis of the traditional model.Through the study of the spatial layout characteristics,3D to 2D, Accelerated multi-mirror algorithm and combined these methods, the pater acommplished module function with the programming language. It conduct comparative analysis between the actual measured data and the caculated results of Ray Tracing model, Okumura-Hata model, COST-231 Hata model.