Three-Dimensional Visualization Engineering Design

Up to now,almost all civil engineering design has been implemented on two-dimensional maps including line map,digital terrain model,etc.Terrain,physiognomy and objects are expressed with lines and specific symbols on these two-dimensional maps,and sometimes some knowledge and experience of cartography is required to correctly identify the character of terrain and physiognomy.In addition,two-dimensional line maps can not accurately and detailedly express the features of terrain and physiognomy.For these reasons civil engineers always dream to design on three-dimensional stereo environment and continuously struggle for the goal.To meet such requirement,three-dimensional visualization engineering design is studied in this paper.It is widely known that a three-dimensional stereo model of terrain can be built by using stereo ortho-images including an orthophoto and its stereo-mate.Such a three-dimensional stereo model can not only be viewed stereoscopically,but also be measured.In addition,with the development of digital photogrammetry,the ortho-images can be produced automatically and rapidly.So,firstly,this paper uses stereo ortho-images to build the three-dimensional stereo model of terrain as three-dimensional the designing environment.According to the requirement of original data and measurement performance,stereo ortho-images can be classified into two categories and the production and mosaic of two kinds of orthophoto stereo-mate have been described.Because measurement accuracy is one of the performances being most concerned in civil engineering design,the emphasis is placed on the measurement performance of stereo ortho-images.This paper discusses both the measurement theory and the measurement accuracy.Test results show that the measurement accuracy can reach a very high level that is enough to meet the requirement of civil engineering design.Three-dimensional engineering design and measurement platform has been built on large-ranged three-dimensional stereo model produced by mosaic orthophoto and its stereo-mate.In the end,the application of this technology to specific engineering design fields is introduced.Compared to the conventional two-dimensional map-based civil engineering design,three-dimensional visualization civil engineering design system has the following characteristics:1) Its measurement performance is good enough to be used in civil engineering design;2) It provides better understanding and recognition of terrain features,objects and does good for protecting environment and farmlands;3) Terrain features and ground objects can be viewed stereoscopically;4) It provides convenience for decision;5) It is easy to be combined with civil engineering design CAD software.