Within the large spectrum of possible VR application areas, automotive applications were among the first to appear, and are among the most demanding. Technology has not been sufficiently sophisticated for many tasks. The troubling thought is that we are happy to push the technology envelope, but don't really know how useful this technology is, or can be. Could I do my job even if I had a real-time, ortho-stereoscopic, head-tracked, multi-viewer, wide-field-of-view, high-dynamic-range display with eye-limiting acuity?

Wood coated with transparent finish has a beautiful and distinctive appearance that is familiar to everyone. Woods with unusual grain patterns. such as tiger, burl, and birdseye figures, have a strikingly unusual directional reflectance that is prized for decorative applications. With new, high resolution measurements of spatially varying BRDFs. we show that this distinctive appearance is due to light scattering that does not conform to the usual notion of anisotropic surface reflection. The behavior can be explained by scattering from the matrix of wood fibers below the surface, resulting in a subsurface highlight that occurs on a cone with an out-of-plane axis. We propose a new shading model component to handle reflection from subsurface fibers, which is combined with the standard diffuse and specular components to make a complete shading model. Rendered results from fits of our model to the measurement data demonstrate that this new model captures the distinctive appearance of wood.

We describe a physically-based Monte Carlo technique for approximating bidirectional reflectance distribution functions (BRDFs) for a large class of geometries by directly simulating optical scattering.The technique is more general than previous analytical models: it removes most restrictions on surface microgeometry.Three main points are described: a new representation of the BRDF, a Monte Carlo technique to estimate the coefficients of the representation, and the means of creating a milliscale BRDF from microscale scattering events.These allow the prediction of scattering from essentially arbitrary roughness geometries.The BRDF is concisely represented by a matrix of spherical harmonic coefficients; the matrix is directly estimated from a geometric optics simulation, enforcing exact reciprocity.The method applies to roughness scales that are large with respect to the wavelength of light and small with respect to the spatial density at which the BRDF is sampled across the surface; examples include brushed metal and textiles.The method is validated by comparing with an existing scattering model and sample images are generated with a physically-based global illumination algorithm.

A general light transfer simulation algorithm for environments composed of materials with arbitrary reflectance functions is presented. This algorithm removes the previous practical restriction to ideal specular and/or ideal diffuse environments, and supports complex physically based reflectance distributions, This is accomplished by extending previous two-pass ray-casting radiosity approaches to handle non-uniform intensity distributions, and resolving all possible energy transfers between sample points. An implementation is described based on a spherical harmonic decomposition for encoding both bidirectional reflectance distribution functions for materials, and directional intensity distributions for illuminated surfaces. The method compares favorably with experimental measurements.