Study on Constructing Roadbed and Terrain Integration Model

3D integrate model of roadbed and terrain is used to build railway 3D scene. The 3D roadbed is constructed with a method called transect-based model. This model is based on the roadbed transect which linked the same character points on border upon transects and make the triangle partition to generate roadbed. How to calculate transect character points based on the roadbed center line and DEM is discussed. Terrain model is TIN (triangular irregular network) model. To integrate these two models seamlessly, a method based on CDT( constrained delaunay triangulation) is used. It deletes the points within outline of roadbed from terrain vertex set and triangles affected by roadbed from triangle set firstly. Then it constructed roadbed model using roadbed vertex set. Finally, merges roadbed and terrain model in a whole. A method of building a railway roadbed and terrain integration model has been presented. It can be applied as an assistant tool for engineering design of railway and science research.