Advanced Design for a Realistic Virtual Brush

This paper proposes a novel algorithmic framework for an advanced virtual brush to be used in interactive digital painting. The framework comprises the following components: a geometry model of the brush using a hierarchical representation that leads to substantial savings in every step of the painting process; fast online brush motion simulation assisted by offline calibration that guarantees an accurate and stable simulation of the brush’s dynamic behavior; a new pigment model based on a diffusion process of random molecules that considers delicate and complex pigment behavior at dipping time as well as during painting; and a user-adaptation component that enables the system to cater for the personal painting habits of different users. A prototype system has been implemented based on this framework. Compared with other virtual brushes, this new system is designed to present a realistic brush in the sense that the system accurately and stably simulates the complex painting functionality of a running brush, and therefore is capable of creating high-quality digital paintings with minute aesthetic details that can rival the real artwork. The advanced features also give rise to a high degree of expressiveness of the virtual brush that the user can comfortably manipulate. http://www.csis.hku.hk/∼songhua/e-brush/ provides supplementary materials for this paper.