The book has all the details required for the complete coverage of either undergraduate level or graduate level course on Computer Aided Design for mechanical engineers, design engineers and civil and architectural engineers. Emphasis has been laid on explaining the concepts and techniques more from the practical and implementation standpoint so that the reader can begin hands-on and to enable the reader to write his own programs and design CAD systems for any mechanical element. Each chapter has a large number of solved and unsolved exercise problems. The book is complemented by several open ended projects, topics as well as partial details of solution, in all the chapters. Close knitting among the geometric modeling, computer aided engineering and applications such as rapid prototyping is a special feature of this book. Spread in two parts containing 11 chapters the book broadly covers: Background of the CAD systems. Curve, surface and solid modeling techniques  Rapid prototyping technology.  Fundamental techniques of computer aided engineering  Fundamentals of mechanical systems Numerical techniques for analysis of mechanical systems Finite difference method and finite element method.