Lecture
This lecture covers the concept of isometries in space, which are transformations that preserve lengths and angles. It explains how isometries can either maintain or reverse orientation, using examples of reflections, rotations, and translations. The lecture also discusses the importance of defining a reference frame in space and how to construct reflections by inverting distances. Practical applications of isometries in 3D machining are highlighted, emphasizing the significance of understanding orientation and reflections for geometric constructions.