A well-known artifact in production rendering from the use of shading normals is the shadow terminator problem: the abrupt interruption of the light’s smooth cosine falloff at geometric horizons. Recent publications introduced several ad-hoc techniques, based loosely on microfacet theory to deal with these issues. We show that these techniques can themselves introduce artifacts and suggest a new technique that is an improvement in many situations. More importantly, we introduce a framework for analyzing these different techniques so artists and researchers can choose appropriate solutions and more reliably predict and understand expected results.

Research Paper of Predictable and Targeted Softening of the Shadow Terminator