I have ready the new (basic) "toon" and "edges" render passes.
My intention is to have a new set of "wireframe" options to be able to create some "non-photorealistic" renders.
Rendering a wireframe is really *not easy* with the current YafaRay architecture, so I've used different methods for obtaining the images I wanted.
"Wireframe" material options and render pass will be calculated at "material" integration level. It should be more finely detailed but will only show triangles (quads will show the "crossing" line).
"Faces edges" will be a render pass calculated at Film level showing the edge contours. In this case, quads will be shown more correctly. However, to calculate the faces edges with the current architecture I had to use indirect methods that are way less precise, so some artifacts and missing or incomplete edges are to be expected, including aliasing in the edges. I've added some parameters that can be accessed in the Render Passes tab for users to fine tune the edges generation as much as possible.
"Object edges" will be the same, but only rendering object edges and contour, more useful for toon-like renders, for example. Limitations are the same as with the Faces Edges.
"Toon" render pass: as I already got the above working, I thought it could be nice to work a bit more and get a full "toon-like" Render Pass. This render pass will take the original image, apply some smoothing and color quantization to make the image more "cartoon-like" and add the Object Edge. The users will be able to choose the edge color, adjust a bit the thickness and smoothing/quantization. This will be only a *very basic* toon render pass, don't expect a perfect contouring, etc!! I didn't even try making an animation yet, I suppose there will some edges changing from one frame to the next, not sure if it will be distracting or not...
Some examples for you to take a look:
"Toon" render pass:
Object Edges pass:
Faces Edges pass:
I hope this will be available in the next YafaRay version. I hope you like it!