Abstract: Herein, the central line of a complex design route is considered as a case study to investigate the generation principle of the threedimensional (3D) engineering route in the Revit modeling space and analyze the accuracy of route data generated using different modeling methods. Deterministic and random accuracy verification methods are adopted to study the construction of the Revit space curve based on Civil 3D and Dynamo software in the Autodesk platform. The following research results are obtained. (1) In the process of upgrading the twodimensional polyline of Revit, the system automatically converts the polyline to a cubic (4th order) space curve with a weight of one nonuniform rational Bspline, thus realizing a smooth transition between adjacent unit polylines. (2) The BCAD method exhibits the largest range of accuracy errors, reaching 15 mm in the x direction. The error interval of the BCAD and CS methods affected by the circular curve of the designed longitudinal section is more concentrated in the z direction. (3) The pointbypoint fitting method with encrypted steps is used for fitting, achieving good performance in the construction of Revit space curve. Moreover, the modeling accuracy can meet the actual engineering requirements. These results provide a reference for subsequent detailed modeling in Revit.

Key words: 3D engineering route construction, modeling accuracy, nonuniform rational Bspline (NURBS) space curve, pointbypoint fitting, Autodesk platform