Construction And Visualization Of 3D Scene Based On TLiDAR

The creation and the visualization of 3D scene has long been a research focus in the multiple disciplines, including disciplines of surveying and mapping. It’s widely applied in the planning, construction, digital city, cultural heritage protection, etc. The TLi DAR(Terrestrial Li DAR) is applied to scenario data collection, using the point cloud data as the basis data of the 3D scene creation, so that giving full play to the advantages of 3D laser scanning technology such as high speed and high precision. But the 3D laser scanning technology appeared late, and the technology development of point cloud processing, modeling and many other aspects is not yet mature. Based on the research and practice of fine modeling, we put forward a modeling based on the feature of TLi DAR point cloud data. The article is combined with the method of Direct X 3D graphics rendering engine visual program design, and introduces the specific implementation of the engineering process in detail. This method can make the advantage of 3D laser scanning technology into full play, and can verify the feasibility of applying 3D laser scanning technology in the field of 3D scene at the same time.This article first introduces the theory and technology based on TLi DAR 3Dscene. After that it introduces the complete engineering and technical process of 3D scene construction and visualization, which mainly includes data acquisition and processing, the construction of a 3D scene model, and the visualization of 3D scene.In the part of the data acquisition and processing,the article will be divided into Data collection and processing. When collecting the data, we need to consider the requirements of the project to develop a detailed plan. Different site conditions need different technical characteristics of the scanners. According to the design of control network, station, target setting. When processing the data, the article studies the process of noise reduction、registration and data reduction. Using professional point cloud processing software for data processing, finally we get the completely full point cloud data model of target scene area.When talking about the drawing of 2D map, the article puts forward the methods to remove objects、reduce data of point could, and to draw a topographic map in Auto CAD. This method can draw 2D map simply and effectively, which is the basis of the 3D scene modeling. When introducing the 3D scene modeling, Considering the differences of ancient and modern architecture, we build model in building components, and the building model is divided into ancientarchitecture model and modern architecture model.According to the characteristics of two kinds of model, ancient architecture uses stylobate, walls, wood structure, roof for geome tric components, and modern architecture uses door, window stairs block, luck receiving gate,luck receiving palace.3D scene uses 3D symbols to express common auxiliary facilities, land scape and so on.In the phase of 3D scene visualization, the article uses the Direct X 11 as graphics rendering engine, and HLSL for GPU programming. Designing a camera to realize the interaction of spatial data browsing, which can read and display the 3D model in the OBJ format,then we add sky boxes, so that form a complete 3D scene. In the end, we realize the function of 3D Scene roaming、inquiring attributes、Displaying the point could and the model at the same time.According to the principle and method, we summarize a set of engineering process about 3D scene creation and visualization based on TLi DAR, and is used in two engineering examples, Taihemen square and BUCEA. Further proving that the possibility of the creation and visualization of 3D scene based on TLi DAR can be applied to practical engineering.