iv About the Authors David A. Madsen is the president of Madsen Designs Inc. (www.madsendesigns.com). David is Faculty Emeritus and the former Chairperson of Drafting Technology and the Autodesk Premier Training Center at Clackamas Community College in Oregon City, Oregon. David was an instructor and department Chairperson at Clackamas Commu- nity College for nearly 30 years. In addition to community college experience, David was a Drafting Technology instructor at Centennial High School in Gresham, Oregon. David is a former member of the American Design Drafting Association (ADDA) Board of Directors, and was honored by the ADDA with Director Emeritus status at the annual conference in 2005. David has extensive experience in mechanical drafting, architectural design and drafting, and building construction. David holds a Master of Education degree in Vocational Administration and a Bachelor of Science degree in Industrial Education from Oregon State University. David is the coauthor of AutoCAD and Its Applications—Basics, AutoCAD and Its Applications—Comprehensive, and other textbooks in the areas of architectural drafting, mechanical drafting, engineer- ing drafting, civil drafting, architectural print reading, mechanical print reading, and building construction. David P. Madsen is the president of Engineering Drafting & Design, Inc., and the vice president of Madsen Designs Inc. (www.madsendesigns.com). Dave provides drafting and design consultation and training for all disciplines. Dave has been a professional design drafter since 1996, and has extensive experience in a variety of drafting, design, and engineering disciplines. Dave has provided drafting and com- puter-aided design and drafting instruction to secondary and postsecondary learners since 1999, and has considerable curriculum, program coordination, and development experience. Dave holds a Master of Science degree in Educational Policy, Founda- tions, and Administrative Studies with a specialization in Postsecondary, Adult, and Continuing Education from Portland State University a Bachelor of Science degree in Technology Education from Oregon State University and an Associate of Science degree in General Studies and Drafting Technology from Clackamas Community Col- lege. Dave is the coauthor of AutoCAD and Its Applications—Basics, AutoCAD and Its Applications—Comprehensive, and other textbooks in the areas of architectural drafting, mechanical drafting, engineering drafting, civil drafting, architectural print reading, mechanical print reading, and building construction. Dennis A. Schwartz is a member of the American Design Drafting Association (ADDA) Board of Directors and serves as executive vice president. Dennis holds a Master of Science degree in Operations Management from the University of Arkansas and a Bachelor of Science degree in Management from Christian Brothers Univer- sity in Memphis, Tennessee. Dennis has ASME Senior Level GD&T certifications for the ASME Y14.5M-1994 and ASME Y14.5-2009 standards. Dennis has more than 45 years of experience in the drafting and design field. Dennis has taught GD&T for his employer, the ADDA, and private companies since 2004. American Design Drafting Association (ADDA) Approved Publication The content of this textbook is considered a fundamental com- ponent to the design drafting profession by ADDA Interna- tional. This publication covers topics and related material, as stated in the ADDA Curriculum Certification Standards and the ADDA Professional Certification Examination Review Guides. Although this publication is not conclusive, with respect to ADDA standards, it should be considered a key reference tool in pursuit of a professional career.