Edge (Toon) Rendering
Blender's toon shaders can give your rendering a comic-book-like or manga-like appearance, affecting the shades of colours, as you may be able to appreciate in A scene with Toon materials.. The effect is not perfect since real comics and manga also usually have china ink outlines. Blender can add this feature as a post-processing operation.
- This makes Blender search for edges in your rendering and add an 'outline' to them.
Before repeating the rendering it is necessary to set some parameters. The Edge Settings opens a window to set these (Toon edge settings (F10).). Edge Settings
- Colour / R/G/B
- The colour of the rendered edges (black by default). Use the sliders or click on the swatch to see the color picker
- The edge's intensity from 0 to 255. 10 gives outline of object against the background, whereas higher settings start to pick up forward or leading edges based on the contrast in the image caused by the geometry of the object and not specular spots caused by lighting. At maximum intensity, Edge will even faintly display geometry subsurf edge lines in areas of imperfect smoothing.
It is possible to separate out the edge layer using a renderlayer dedicated to that purpose. The alpha channel is 0 where there is no edge, and 1 where the edge is. By separating out the edge layer, you can blur it, change its color, mask it, etc. The image to the right shows how to do this. I created an Edge renderlayer that only has the Sky and Edge layers (I included sky so that we get the world color later on in the composite output). The other renderlayer omits the Edge layer, so it returns just the normal image. On the output panel I enabled Edge with a width of 10 in black. I run that layer through a blur node. Using the Alphaover node, I then composite the cube on top of the blurred edge. The result gives a soft-shadow kind of effect. Note that Premultiply is set because the Edge image already has an alpha of 1.0 set.