This lecture covers the concepts of surface and curvature, focusing on the TopSolid 7 software and its application in education. It explains the generation of different sections, resolution of inclinations, and the use of various tools for modeling surfaces. The lecture also delves into the curvature of normal sections, the Gauss curvature, and the main sections defining the curvature of a surface. It discusses the concept of Gaussian curvature, its independence of surface orientation, and its significance in distinguishing between convex and concave regions. The lecture concludes with practical examples and demonstrations of curvature calculations in different software tools.