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Flattening 3D objects using silhouettes
Author(s): Domingo Martín, Jean-Daniel Fekete, J. C. Torres.
Article: Computer Graphics Forum (EG'02), Vol. 21, No. 3,
2002.
[BibTeX] 
Abstract:
An important research area in non-photorealistic rendering is the obtention of silhouettes. There are many methods to do this using 3D models and raster structures, but these are limited in their ability to create stylised silhouettes while maintaining complete flexibility. These limitations do not exist in illustration, as each element is plane and the interaction between them can be eliminated by locating each one in a different layer. This is the approach presented in this paper: a 3D model is flattened into plane elements ordered in space, which allows the silhouettes to be drawn with total flexibility.
TicTacToon: A Paperless System for Professional 2D Animation
Jean-Daniel Fekete, Erick Bizouarn, Eric Cournarie, Thierry Galas, Frederic Taillefer.
SIGGRAPH '95: Proceedings of the 22nd annual conference on Computer graphics and interactive techniques, pp. 79--90, New York, NY, USA, ACM Press,
1995. [BibTeX]