.
An Interface for Sketching 3D Curves
Jonathan M. Cohen, Lee Markosian, Robert C. Zeleznik, John F. Hughes, Ronen Barzel.
Proceedings of the 1999 ACM Symposium on Interactive 3D Graphics, pp. 17--21,
1999. [BibTeX]
Harold: A World Made of Drawings
Jonathan M. Cohen, John F. Hughes, Robert C. Zeleznik.
1st International Symposium on Non-Photorealistic Animation and Rendering (NPAR'00), pp. 83--90, Annecy, France, June 05 - 07,
2000. [BibTeX]
SKETCH: An Interface for Sketching 3D Scenes
Author(s): Robert C. Zeleznik, Kenneth P. Herndon, John F. Hughes.
Proceedings: Proceedings of SIGGRAPH '96, August,
1996.
[BibTeX] 
Abstract:
Sketching communicates ideas rapidly through approximate visual images with low overhead (pencil and paper), no need for precision or specialized knowledge, and ease of low-level correction and revision. In contrast, most 3D computer modeling systems are good at generating arbitrary views of precise 3D models and support high-level editing and revision. The SKETCH application described in this paper attempts to combine the advantages of each in order to create an environment for rapidly conceptualizing and editing approximate 3D scenes. To achieve this, SKETCH uses simple non-photorealistic rendering and a purely gestural interface based on simplified line drawings of primitives that allows all operations to be specified within the 3D world.