| The study on Scientific Visualization has great achievement recent years, but there are many questions in methods of Visualization which are waiting to be solved, such as how to enhance the speed of volume rendering, how to show the data field visualization images dynamically. Solving these questions will extend the application fields of Visualization. In analysis of dam seismic response, the main visualization function of post treatment software mostly used is 2D display. The 3D visualization function is very limited, which only show the surface stress distribution and surface displacement changes, can not show the changing process of field value distribution inside dam, and not reach the satisfactory level of visualization.This dissertation fully considers the special feature of dam seismic response data, the study of visualization method for dam seismic response data is as this paper's main content, research and development of dam seismic response visualization system is as this paper's last aim, this paper presents several feasible methods of data visualization. The main contents studied in this dissertation may be summarized as follows:(1) Based on the basis thought of St.Andrew in finite element subdivision, draws off contours in dam seismic response data which is defined on four-node irregular nets, and draws out the integer curves by colors. Using scanning line method, calculates the field value of image element on dam section and relative color value, draws out the color contour which colors change continually. The section field value distribution of dam seismic response can be seen clearly.(2) Presents a visualization method-multiple section color contour display, whichcan not only display the stress diagram of single dam section, but also make the stress diagram on several dam section be showed and be compare. This method is a simple and efficient method of volume data visualization.(3) The concentrative part of field value can't be judged exactly on the static picture of classical volume rendering. In order to remedy this kind of shortage, this paper presents a quick volume rendering method, for the finite element data field of dam seismic response, choices the slicing direction relying on the element surface which normal line has the smallest included angle with the view direction, slices elements to many quadrilaterals, blends the colors of these quadrilaterals by using OpenGL blending technology, and thensuperimposes all elements one by one. This method accelerates the speed of volume rendering, thus, we can observe dynamic pictures of volume rendering and analyzes the concentrative part of field value clearly.(4) The data of dam seismic response is changeable by time. In order to visualize this kind of data, this paper presents several 3D dynamic visualizing methods based on neU surface, volume rendering and multiple-section. By these methods, the field value's distribution of whole dam can be showed clearly, dynamic rendering for large volume data can be achieved, people can understand the process of dam seismic response promptly and exactly and make correct decision.(5) Explains the fractal IPS method by example, deduces the actual iterative formulas, gives the method of generating terrain map by fractal interpolating surface, presents a method of getting same random parameter at the same depth of recursion, which method can solve the cleft in midpoint deflection method. Draws out mountain shape of visualization scene by triangle midpoint deflection method and quadrilateral midpoint deflection method. Then constructs the mountain shape and stream channel of reservoir field by continuous quadrilateral chips, and constructs channel bed by fractal surface, shows the whole visualizing scene truly.Visualization is a interdiscipline which relates to Computer Graphics, Image Processing, Computer Aided Design, Computer Visual Sense, People and Computer Interactive Technology, etc. The application of visualization in civil engineering also touches many real engineering prob...
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