Using dynamic teach-while-doing method children learn how to use FreeCAD’s Part workbench to model two robot toy projects. The book introduces students to the concepts of: the Cartesian coordinate system that describes three-dimensional space, conversion of inches to millimeters, the Part workbench toolbars, use of primitive solid shapes, use of Boolean operations, print-in-place design tolerances, exporting of .STL files, using Netfabb Basic to check .STL files for errors, and 3D printer settings. FreeCAD’s ability to be downloaded and ran without connection to the Internet allows it to be a terrific resource for any STEM education project worldwide.