.
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
Robert D. Kalnins, Lee Markosian, Barbara J. Meier, Michael A. Kowalski, Joseph C. Lee, Philip L. Davidson, Matthew Webb, John F. Hughes, Adam Finkelstein.
ACM Transactions on Graphics, Vol. 21, No. 3, pp. 755--762, July,
2002. [BibTeX]
WYSIWYG NPR: Interactive Stylization for Stroke-Based Rendering of 3D Animation
Author(s): Robert D. Kalnins.
PhD Thesis: Princeton University, June,
2004.
[BibTeX] 
Abstract:
Artists and illustrators have developed a large repertoire of techniques to communicate information effectively using traditional media. Recent work in computer graphics has begun to leverage these techniques in the form of non-photorealistic rendering (NPR) algorithms for 3D, but, to date, little research has addressed flexible, interactive tools to make such algorithms accessible to content creators. In this dissertation we demonstrate the importance of developing these tools for NPR. In particular, we show that "hands-on" NPR systems can provide the designer with new levels of aesthetic flexibility, and the means to achieve effects tedious or even impossible to attain by traditional methods.
We approach this open problem for stroke-based NPR of animated 3D geometry. Our system employs a tablet interface to provide the designer with an interactive paradigm in which stroke effects are sketched directly into the scene. The artist imparts his unique aesthetic by sketching strokes over the outlines of objects, and drawing details and hatching effects onto their surfaces...