I've been working on solving the problem of making clean stylized cartoon shading, specifically for anime style faces. Anyone familiar with 3D anime from shows or games will recognize that dynamic toon shading usually looks bad, or is often avoided entirely. My goal as a 3D artist is to illustrate my own comics, so this is something that could be fixed in post production. But I got curious about why it looked bad, and if it could just be fixed in some convenient way.
