Surface forming and virtual model of simulation based on IGES

Abstract

Modelling, sharing and transmission of three-dimensional (3D) graphics data are essential for extensive application of 3D virtual simulation technology. To achieve data transmission between general modelling software and a 3D virtual simulation system, and real-time interaction with the simulation model, the topology of the Initial Graphics Exchange Specification (IGES) has been studied in depth, and the storage structure of all geometry element information has been given. Non-uniform rational B-spline (NURBS) surfaces are used to construct complicated dimensional surfaces. The arithmetic of extracting the equation parameters of NURBS surfaces from the general rotation surfaces’ parameters is derived in detail. The respective data structures for the NURBS curve entity, line entity and composite curve entity and their program frameworks consistent with IGES are defined and designed. All data structures are stored as nodes in the respective chain lists and, in turn, all nodes are finally encapsulated in different classes. Description of the base surfaces of the IGES data and trimming of the outer and inner boundaries are realised with an Open Graphics Library, which is based on the reading data stored in the data chain list. Regeneration of complicated dimensional surfaces and interaction with the model are accordingly realised. This program reads an IGES file and the model is displayed successfully.

Keywords:

• Initial Graphics Exchange Specification
• virtual model of simulation
• complicated surface
• 3D model

Acknowledgements

The authors are highly indebted to the School of Mechanical Engineering, Tianjin University, Tianjin, China, for the support provided for the research work. Thanks are also due to the Ministry of Science and Technology of China for providing the funds for the research.