Traditional design of roadway was usually based on the method of CAD. That could not embody the geological features where the roadway was through, and also could not reflect the spatial relations of the roadways network. The design of roadway can be divided into two parts: the section and the axis. The goal is developing a design system with the function of optimization design for roadway in 3D environment. Geological models are established in 3D environment first. The roadway model is established by constructive solid geometry (CSG) method, and the relationships between roadway, axis and section are linked at the...