.
A Developer's Guide to Silhouette Algorithms for Polygonal Models
Tobias Isenberg, Bert Freudenberg, Nick Halper, Stefan Schlechtweg, Thomas Strothotte.
IEEE Computer Graphics and Applications, Vol. 23, No. 4, pp. 28--37, July/August,
2003. [BibTeX]
Game Programming Gems 4
Bert Freudenberg, Maic Masuch, Thomas Strothotte.
Andrew Kirmse, Real-Time Halftoning: Fast and Simple Stylized Shading, pp. 443--440, Charles River Media,
2004. [BibTeX]
Non-Photorealistic Shading in an Educational Game Engine
Bert Freudenberg, Maic Masuch.
Production Process of 3D Computer Graphics Applications - Structures, Roles and Tools, Snowbird, Utah, USA, June 1 - 4,
2002. [BibTeX]
OPENNPAR: A System for Developing, Programming, and Designing Non-Photorealistic Animation and Rendering
Nick Halper, Tobias Isenberg, Felix Ritter, Bert Freudenberg, Oscar E. Meruvia Pastor, Stefan Schlechtweg, Thomas Strothotte.
11th Pacific Conference on Computer Graphics and Applications (PG'03), pp. 424, Canmore, Canada,
2003. [BibTeX]
Real-Time Animated Stippling
Oscar E. Meruvia Pastor, Bert Freudenberg, Thomas Strothotte.
IEEE Computer Graphics and Applications, Vol. 23, No. 4, pp. 62-68,
2003. [BibTeX]
Real-Time Halftoning: A Primitive For Non-Photorealistic Shading
Author(s): Bert Freudenberg, Maic Masuch, Thomas Strothotte.
Proceedings: Eurographics Workshop on Rendering, pp. 1–4,
2002.
[BibTeX] 
Abstract:
We introduce halftoning as a general primitive for real-time non-photorealistic shading. It is capable of producing a variety of rendering styles, ranging from engraving with lighting-dependent line width to pen-and-ink style drawings using prioritized stroke textures. Since monitor resolution is limited we employ a smooth threshold function that provides stroke antialiasing. By applying the halftone screen in texture space and evaluating the threshold function for each pixel we can influence the shading on a pixel-by-pixel basis. This enables many effects to be used, including indication mapping and
individual stroke lighting. Our real-time halftoning method is a drop-in replacement for conventional multitexturing and runs on commodity hardware. Thus, it is easy to integrate in existing applications, as we demonstrate with an artistically rendered level in a game engine.
Real-Time Stroke Textures
Bert Freudenberg.
Technical Sketch presented at SIGGRAPH 2001,
2001. [BibTeX]
Real-Time Stroke-Based Halftoning
Bert Freudenberg.
Otto-von-Guericke-Universität, Magdeburg,
2003. [BibTeX]
Subdivision for Line Drawings
Bert Freudenberg.
2001. [BibTeX]
The Computer-Visualistik-Raum: veritable and inexpensive presentation of a virtual reconstruction
Bert Freudenberg, Maic Masuch, Niklas Röber, Thomas Strothotte.
Proceedings of the 2001 conference on Virtual reality, archeology, and cultural heritage (VAST '01), pp. 97--102,
2001. [BibTeX]