The aim of this book is to show how to use Tecnomatix Process Simulate software to design and validate modular fixtures concurrent with process planning tasks. The unchangeable need of securing and locating parts during different manufacturing processes turned the fixtures to key elements in production industries, but the iterations between design engineers and manufacturing planners because of late collision detection of the part/fixtures with robots cost a lot of time and money. Therefore, the lead-time can be reduced by developing tools and/or methods for early verification of the fixtures during the simultaneous engineering phase. To do so, Different aspects of fixture designing, modeling and simulating is investigated in this study. The focus of this book is on the fixtures designed for robotic applications specifically in Automotive Body in White lines.