.
Coherent stylized silhouettes
Robert D. Kalnins, Philip L. Davidson, Lee Markosian, Adam Finkelstein.
ACM Transactions on Graphics, Vol. 22, No. 3, pp. 856--861, July,
2003. [BibTeX]
WYSIWYG NPR: Drawing Strokes Directly on 3D Models
Author(s): Robert D. Kalnins, Lee Markosian, Barbara J. Meier, Michael A. Kowalski, Joseph C. Lee, Philip L. Davidson, Matthew Webb, John F. Hughes, Adam Finkelstein.
Article: ACM Transactions on Graphics, Vol. 21, No. 3, pp. 755--762, July,
2002.
[BibTeX] [DOI] 
Abstract:
We present a system that lets a designer directly annotate a 3D model with strokes, imparting a personal aesthetic to the non-photorealistic rendering of the object. The artist chooses a "brush" style, then draws strokes over the model from one or more viewpoints. When the system renders the scene from any new viewpoint, it adapts the number and placement of the strokes appropriately to maintain the original look.
WYSIWYG NPR: Interactive Stylization for Stroke-Based Rendering of 3D Animation
Robert D. Kalnins.
Princeton University, June,
2004. [BibTeX]