The product page for SF Anime Character Builder mentions the Camera Magic: ToonyCam Pro product for rendering anime-style characters. I've used ToonyCam Pro before to good effect, but as you can see, Sketchy can produce good results too. ToonyCam Pro is used with the 3Delight renderer, while Sketchy is used with the Iray renderer. All of my new images this month use Sketchy with Iray for creating the draw styles.
Whether I use ToonyCam Pro or Sketchy, I have the most difficulty with the eyes. If I use the SF Anime Character Builder, it's not really a problem, because that tool creates nicely stylized eyes. If I use models that don't include stylized eyes, applying a Sketchy draw style to the eyes without also adding an anime-style shader or material to the eyes often doesn't give good results.
One trick I've found when working with non-stylized eyes is to apply the draw style to the Eye Reflection surface, and then set the opacity of the Eye Reflection to roughly 10-20%. This keeps the original images for the Cornea, Iris, and Pupil surfaces intact, while laying the draw style over them by way of the Eye Reflection surface. Results vary with this technique.
In most of the images, I applied Sketchy shaders to all the surfaces in the scene, with possible exceptions for the eyes. A problem arises when the image background is produced due to render settings, in which case you don't have a background object to apply a shader to. In cases like this, I created a plane primitive and placed it behind all the objects in my scene, facing the camera. I then applied the desired Sketchy shader to this plane primitive, and lowered the opacity of the plane's surface to something that allowed the plane to blend well with the background.
In one image, I used a plane primitive in the foreground, between the camera and all the other objects in the scene, applying a Sketchy shader to the plane and lowering the opacity. This technique allowed me to apply the shader uniformly across the entire image. It also dims the image, so I raised the saturation level to compensate.
Now that you know my techniques, see if you can spot where I did or didn't use them on my Toon page. What do you think of the toon style?