Book excerpt: The Autodesk® Inventor® program was introduced in 1999 as an ambitious 3D parametric modeler based not on the familiar Autodesk® AutoCAD® software programming architecture but instead on a separate foundation that would provide the room needed to grow into the fully featured modeler it is now, more than a decade later. Autodesk Inventor 2015 continues the development of Autodesk Inventor with improved modeling, drawing, assembly, and visualization tools. Autodesk has set out to improve this release of Autodesk Inventor by devoting as much time and energy to improving existing tools and features as it has to adding new ones. With this book, the sixth edition of Mastering Autodesk® Inventor® 2015 and Autodesk® Inventor LT™ 2015, I have set out to update the existing pages and add new content and exercises. In these pages, you will fi nd detailed information on the specifi cs of the tools and the principles of sound parametric design techniques. Some readers will fi nd this book works best for them as a desktop reference, whereas others will use it primarily for the step-by-step tutorials. With this in mind, I’ve worked to shape the pages of this book with a mix of reference material, instructional steps, and tips and hints from the real world.