Simulating Artistic Brushstrokes Using Interval Splines

In this paper we present a novel method of simulating the elegant brushstrokes found in calligraphic lettering and painting. Such simulations have earlier been attempted with physically based or texture-mapped approaches, methods that succeeded in producing aesthetic, but also computationally intensive, results. We introduce a brushstroke model based on a parametric curve, the interval spline. By defining brush effects as mathematical constraints between knots, we generate artistic strokes that render faster than earlier methods and are also resistant to scaling. More significantly, because the construction of the interval spline curve is based on changes in the shape of the brush as it moves along a path, variations within a single stroke not fully modeled with earlier attempts are inherently captured by this representation. We present a system for painting with interval spline strokes and discuss a number of examples created with this method.