Non-Photorealistic Computer Graphics Library

Simulation of sparkling and depth effect in paints

Author(s): Roman Durikovic, William L. Martens.
Proceedings: Proceedings of the 19th ACM Spring Conference on Computer Graphics - SCCG2003, K.I. Joy and L. Szirmay-Kalos, pp. 207--213, Budmerice, Slovakia, 2003.
[BibTeX]

Abstract:
This paper reports on our attempts to simulate light reflection from surfaces that exhibit sparkling and depth effects that are associated with paint coatings containing metallic flakes. The novelty of the approach is to explicitly model the sparkle geometry for rendering the surface of a graphic object. The light scattering within the system of metal flakes or particles creates the sparkling and glare effects with radial streaks of light around high intensity particles. The 3D geometry of the simulated flakes creates a view-dependent reflectance pattern that makes the surface appear differently in the two images rendered for each eye's view in a stereoscopic display. The results of 3D geometry-based rendering are then compared to the surfaces rendered using 2D random dot patterns that provide no cues to depth variation at the surface. Stereoscopic display of 3D objects with and without the 3D geometry-based surface rendering was used to validate the difference in perceived depth effects associated with the two cases. To confirm the applicability of the technique, we adopted a standard test in common use by paint designers in which the appearance of paints with different sparkle density is observed on silver plates. Our results showed typical variation in sparkling on plates with different statistical distributions of sparkles, which confirmed the robustness of the 3D sparkle modeling system. In a final application test, the technique was used to simulate the appearance of an expensive variety of Japanese lacquerware made using the nashiji technique.