For highly diffuse rendering, some materials like snow are commonly accomplished through the use of simplified local illumination models for ambient and diffuse light. In reality, however, for a given point on a surface, the incident light is not only contributed from directional light sources, but also from backscattering from nearby surfaces. To account for this effect, a new technology has been developed, using Curvature Maps for Rendering. This rendering algorithm integrates normal mapping with curvature mapping into a local illumination model to solve the previous mentioned problem. In this report, I will derive different measures to calculate curvature maps from normal maps and I evaluate their suitability for rendering.