9.1 INTRODUCTION

The need for illustrating, visualizing, and documenting mechanical designs prior to production has existed ever since human beings began creating machines, mechanisms, and products. Over the last century, methods for achieving this function have evolved dramatically from the blackboard illustrations of the early twentieth century and from manual drafting systems that were commonplace 50 years ago to today s automated 3D solid modeling software. As computer technology has advanced, so have the tools designers and product engineers use to create and illustrate design concepts. Today, powerful computer hardware and software have supplanted the drafting tables and T-squares of the 1960s and have advanced to the point of playing a pivotal role in not only improving design visualization but also in driving the entire manufacturing process.