Group 3D
3d as a good suspect to inform 2d graphics on less path-dependant approaches
blender collision
baking http://wiki.blender.org/index.php/Doc:2.5/Manual/Render/Bake
padding
render as vectors? http://freestyle.sourceforge.net/GALLERY/CARTOON/dirindex.php
objects as predator or attractor
http://en.wikipedia.org/wiki/Scene_graph
http://verse.blender.org/faq/