Painterly rendering

You may have noticed my studies on NPR rendering techniques, some of which are on display in my Playground. On this project I’ll finally be able to make use of many, if not all, of the techniques I’ve been developing. For Bagel 2 I had various reasons to go with the more common (yet easier to produce) semi-realistic style… but not this time, here it’s cartoon all the way!!

PainterMan

One of my favorite techniques is “PainterMan”, a RenderMan shader I named after the natural and painterly images it produces. I’ve improved some features today to perhaps apply it on a character in my short film.
For testing purposes I’ve rendered the “Stanford Dragon”, playing with various settings in PainterMan to simulate different artistic styles. Note that all these images come straight from the 3d renderer, in this case 3delight, which is to say there’s absolutely no filters, plug-ins or other foul trickery in post involved…

The algorithm is based loosely on ideas outlined in “A Painterly Approach to Human Skin” by Matt Kaplan but with a few extra bells and whistles, for example an additional mode to simulate watercolors. The colors are determined by a texture map that acts similar to an environment map in that the color is chosen according to the angle that light falls onto the surface. This can become a problem: During camera movement, the texture tends to “crawl” all over the surface, something I’ll need to work on before I can incorporate the shader in production…