Three-dimensional modeling has emerged as the modern method of CAD use in product design and manufacturing, revolutionizing the way industry integrates computers into the design process. Commercial 3-D modeling packages, available since the mid 1980s, have become commonplace in a wide range of industries.

Two-dimensional CAD has, in many ways, matured to the point where simply using a more powerful computer will not have much of an impact on how well a 2-D CAD program functions. Like traditional drafting methods, 2-D CAD programs attempt to represent objects in two dimensions; in fact, the packages were developed to be computer drafting tools, with the end product being a drawing on paper. In contrast, a 3-D computer model is more like a real object, not just a drawing of the object; 3-D CAD is considered a computer modeling tool.

This chapter introduces the possibilities for, and the limitations of, integrating 3-D CAD operations into the design process. While 3-D modeling software has enhanced such integration, current computer models fall short of being a complete replacement for physical objects, because of the mathematical and computational limitations of existing computer software.

The chapter outlines the most common approaches for generating 3-D computer models, in addition to how these models are viewed and modified on the computer. The chapter concludes with examples of 3-D computer modeling applications in the design process.