This book addresses a concept of a software system that analyzes freeform surfaces in terms of machinability with definable NC milling tools. The local curvatures of the respective freeform surface play a central role in the context of the analysis and are examined alongside a raster consideration of the surface and the NC milling tool. Three mathematical methods for calculating the surface quality characteristic of curvature are presented and conceptually implemented into the prototype software system. The mathematical approaches for curvature calculation include analytical, numerical, and semi-numerical variants, each with specific qualitative characteristics within the framework of an algorithmic implementation for integration into the software system. Ultimately, the software system is presented as a prototype of a system to be implemented in the C++ programming language.