Shading-interval constraints for normal map editing

Abstract

Normal mapping is a compact representation to create visually rich shapes and shading effects. In this paper, we introduce a new paint-based approach to edit a normal map according to the intended shading, from realistic to non-realistic ones. For this purpose, we have formulated a normal-from-shading operation as a quadratic problem that makes use of intervals on shading. This approach ensures that the resulting normal map visually corresponds to the user-designed shading.