Abstract: Sketch-based interfaces are becoming a useful methodology for interaction with a wide range of applications. Drawing is a natural and simple paradigm for designers. One of the problems in most of the current generation of such interfaces is that designers are forced to use single strokes where they may prefer to use many strokes while drawing with traditional tools such as a pencil.

In this work we have addressed this problem by analyzing multiple strokes and replacing them with a single stroke that makes a reasonable estimate of the designer's intention. Our solution recursively subdivides space stopping where either there is only a single stroke, or several strokes that have a proper ordering using principal component analysis. The subspaces are then reconnected, and the orderings are joined to create the control points of a single B-spline curve. The resulting curve is very noisy due to the multitude of strokes. A multi-resolution technique that makes use of reverse subdivision has been used to fit a smooth B-spline curve.