Capstone Definition

CSC2521 Winter 2010: Topics in Computer Graphics:

Sketching: interaction, modeling and perception.

Sketch-based interfaces have often been touted as a “natural” approach to interactive design. While sketching is indeed a promising medium of visual communication, there are a number of inherent limitations in the motor control of the human hand, human drawing skill, perception and the ambiguities of inference, that make the leap from 2D sketching to 3D visual concepts a challenging task. This seminar style course will read papers and present results on various aspects of a sketch-based modeling pipeline: gesture drawing, the creation, processing and filtering of strokes to create the metaphor of a virtual 2D sketchbook, an understanding of human limitations in perceiving or drawing accurate 2D projections of imagined 3D shapes, and finally approaches that facilitate the leap from 2D sketches to 3D models despite these limitations. We will discuss the relative artistic and computational merits of various sketching philosophies: single-view vs. multi-view, symbolic vs. perceptual, precision vs. free-form and static vs. dynamic and test various hypotheses as small experimental projects.

Professor:

Karan Singh (http://www.dgp.toronto.edu/~karan)

Grading scheme:

- paper presentation (1 or 2 depending on the number of students) 50%

- implementation and demo of a small self-contained idea on sketch-based interactive design 40% (due by early April. 2010)

- project report (1-2 pager) 10% (due by early April 2010)

Duration:

The class will meet once a week R 12-2 (first meeting on the 7th to discuss the agenda and day and time of the weekly meeting), in BA 5181, the Dynamic Graphics Project lab (http://www.dgp.toronto.edu).

Slides

First meeting (Introduction)

Papers:

jan 20 Overall: ILoveSketch, EverybodyLovesSketch (project page)

jan 27 Drawing perception:

Why cant most people draw what they see? Cohen and Bennett 1997

Where do people draw lines? siggraph 08

How well do line drawings depict shape? siggraph 09

feb 3 Gestures (stroke processing):

Xiang Cao, Ravin Balakrishnan. (2005). Evaluation of an online adaptive gesture interface with command prediction. Proceedings of GI 2005, Graphics Interface Conference. p. 187-194.

Xiang Cao, Shumin Zhai. (2007). Modeling human performance of pen stroke gestures. Proceedings of CHI 2007, ACM Conference on Human Factors in Computing Systems. p. 1495-1504. Demo Program

Gestures without Libraries, Toolkits or Training: A $1 Recognizer for User Interface Prototypes

Appert, C., Zhai, S., Using strokes as command shortcuts: cognitive benefits and toolkit supportProc. ACM CHI 2009 Conference on Human Factors in Computing Systems. pp. 2289-2298.

feb 17: Strokes for animation (gestural instances):

Motion Doodles

As rigid as possible shape manipulation

feb 25: 2D to 3D (stroke inference)

Analytic Drawing of 3D Scaffolds

mar 3 NPR and sketching (stroke appearance):

Line Drawings for 3D models (SIGGRAPH course notes 2008)

mar 10 2D to 3D (stroke inflation):

SKETCH: An interface for sketching 3D scenes, by R. C. Zeleznik, K. Herndon, and J. F. Hughes. Proceedings of SIGGRAPH '96.

Teddy