Ink-and-Ray: Bas-Relief Meshes for Adding Global Illumination Effects to Hand-Drawn Characters

We present a new approach for generating global illumination renderings ofhand-drawn characters using only a small set of simple annotations. Our systemexploits the concept of bas-relief sculptures, making it possible to generate3D proxies suitable for rendering without requiring side-views or extensiveuser input. We formulate an optimization process that automatically constructsapproximate geometry sufficient to evoke the impression of a consistent 3Dshape. The resulting renders provide the richer stylization capabilities of 3Dglobal illumination while still retaining the 2D hand-drawn look-and-feel. Wedemonstrate our approach on a varied set of hand-drawn images and animations,showing that even in comparison to ground-truth renderings of full 3D objects,our bas-relief approximation is able to produce convincing global illuminationeffects, including self-shadowing, glossy reflections, and diffuse colorbleeding.