The aim of this paper is to trace the evolution of modular fixturing systems (MFS) and its impacts on high-precision machining industries. The strength of current computer-aided tools for modular fixture design is reviewed together with their weaknesses. Recent trends in the integration of knowledge-based and 3D solid CAD techniques for modular fixture design, pricing and inventory control are described. The functionality, design and knowledge representation techniques of a 3D Modular Fixture Design EXpert, MOFDEX system forms the core of this paper.