Despite revolutionary advances in how images are recorded, manipulated, and reproduced, our ability to re-create the visual experience remains remarkably limited. Few realistic computer models exist for the characteristic appearance of natural materials such as marble, wood, coral, or skin, or man-made ones such as color-shifting automotive paints. Digitizing and creating realistic images of these substances involves reproducing their interaction with light: the way light is reflected from surfaces, or scattered and absorbed within the materials. Full reproducibility also involves "printing" a material as a real, physical object that modulates the light around us. However, it is currently impossible to output complex appearance the way we print color on a paper with fixed gloss, or create shapes using a 3D printer. This project encompasses a comprehensive, collaborative research agenda in computer graphics and related areas, to develop an end-to-end framework for acquiring, representing, and fabricating complex appearance, as well as to understand how it is perceived by the human visual system.
The enabling technical idea of the project is to treat materials as thin three-dimensional volumes populated with general scattering sites. This is a radical departure from the hitherto standard approach in computer graphics, which has studied materials purely as surfaces. The volumetric representation subsumes and generalizes the diverse set of conventional representations that currently exist in graphics, including surface-based notions such as bidirectional reflectance (BRDF), spatially varying BRDF, and subsurface scattering distributions (BSSRDF). Moreover, it enables fundamentally improved approaches to efficient yet general acquisition, fast and realistic rendering, and fabrication of objects exhibiting phenomena beyond simple surface reflectance and spatially homogeneous subsurface scattering.
