Computational Predictions of the Hypersonic Material Environmental Test System Arc-Jet Facility.

The Hypersonic Materials Environmental Test System arc-jet facility located at the NASA Langley Research Center in Hampton, Virginia, is primarily used for the research, development, and evaluation of high-temperature thermal protection systems for hypersonic vehicles and reentry systems. In order to improve testing capabilities and knowledge of the test article environment, a detailed three-dimensional model of the arc-jet nozzle and free-jet portion of the flow field has been developed. The computational fluid dynamics model takes into account non-uniform inflow state profiles at the nozzle inlet as well as catalytic recombination efficiency effects at the probe surface.

Looking against the light: how perception of translucency depends on lighting direction.

Translucency is an important aspect of material appearance. To some extent, humans are able to estimate translucency in a consistent way across different shapes and lighting conditions, i.e.

Heterogeneous Subsurface Scattering Using the Finite Element Method.

Materials with visually important heterogeneous subsurface scattering, including marble, skin, leaves, and minerals are common in the real world. However, general, accurate, and efficient rendering of these materials is an open problem. In this paper, we describe a finite element (FE) solution of the heterogeneous diffusion equation (DE) that solves this problem.

Accurate direct illumination using iterative adaptive sampling.

This paper introduces a new multipass algorithm for efficiently computing direct illumination in scenes with many lights and complex occlusion. Images are first divided into 8 x 8 pixel blocks and for each point to be shaded within a block, a probability density function (PDF) is constructed over the lights and sampled to estimate illumination using a small number of shadow rays. Information from these samples is then aggregated at both the pixel and block level and used to optimize the PDFs for the next pass.