Various 3D modeling software has been developed for design and manufacturing. Most of the commercially available software uses native file formats, which may not be able to be read or understood by other software. This paper deals with the development of a generic approach of a 3D model conversion program for virtual manufacturing (VM), using a lexical analyzer generator Lex and the Open Graphic Library (OpenGL). The program is able to convert 3D mesh data between four universal file formats, i.e., Stereolithography (STL), Virtual Reality Modeling Language (VRML), eXtensible Markup Language (XML), and Object (OBJ). Simple assembly functions can be applied to the imported models. The quaternion angle is used for object rotation to overcome the problem of gimbal lock or a loss of one degree of rotational freedom. The program has been validated by importing the neutral format models into the program, applying the transformation, saving the new models with a new coordinate system, and lastly exporting into other commercial software. The results showed that the program is able to render and re-arrange accurately the geometry data from the different universal file formats and that it can be used in VM. Therefore, the output models from a VM system can be transferred or imported to another VM system in a universal file format.

关键词： Virtual manufacturing,  Lex,  OpenGL,  Three-dimensional mesh data,  Quaternion,  Neutral format