Filippo Veniero presents a tutorial on the use of Freestyle.
Every day, 3D artists spend hours working on their computers trying to get photorealistic images, but sometimes we need to have images styled more like a comic; luckily Blender can do them, using the Freestyle option! Freestyle is an edge and line based non-photorealistic render engine. It generates 2D line drawing from a set of objects; lines can be stylized in a lot of ways (different line colors and thickness or by adding random displacements) to produce artistic (hand drawn) or technical (blueprint) styles. Freestyle for Blender has two complementary modes for line stylization: the Parameter Editor and the Python Scripting mode. In this tutorial we'll use the first one.