“Real-time Simulation of Thin Paint Media”

The possibility of experimenting with various techniques and paint media, as well as the ability of introducing a wide range of digital tools, makes a digital equivalent of the traditional painting process a valuable asset for both novices and experienced artists. Existing work on applications for thin watery paint is mainly focused on automatic generation of painterly-style images from input images, ignoring the fact that painting is a process that intuitively should be interactive. Efforts to create real-time interactive systems are limited to a single paint medium and results often suffer from a trade-off between real-timeness and simulation complexity.
We present an application for real-time interactive creation of im- ages with thin watery paint, including watercolor, gouache and Chinese ink. Our canvas model adopts stable fluid dynamics algorithms to transfer pigment densities and water quantities on top of the canvas. Heuristic rules handle the deposition of pigment within the irregularities of the canvas surface, as well as the evaporation, ab- sorption and capillary diffusion of water inside the canvas structure. We extend our previous work on a parallel implementation [Van Laerhoven et al. 2004] with a new approach suitable for graphics hardware, the Kubelka-Munk diffuse reflectance model and the capability to produce paintings with paint media related to water- color, like gouache and Chinese ink. The application can also generate animated paintings from stroke curve data.

Baxter, W., Wendt, J., and Lin, M. C. 2004. Impasto: A realistic model for paint. In Proceedings of the 3rd International Symposium on Non-Photorealistic Animation and Rendering, 45–46.
Curtis, C. J., Anderson, S. E., Seims, J. E., Fleischer, K. W., and Salesin, D. H. 1997. Computer-generated watercolor. In Proceedings of the 24th annual conference on Computer graphics and interactive techniques, ACM Press/Addison-Wesley Publishing Co., 421–430.
Stam, J. 1999. Stable fluids. In Siggraph 1999, Computer Graphics Proceedings, Addison Wesley Longman, Los Angeles, A. Rockwood, Ed., 121–128.
Van Laerhoven, T., Liesenborgs, J., and Van Reeth, F. 2004. Real-time watercolor painting on a distributed paper model. In Proceedings of Computer Graphics International 2004, 640–643.