The team of Visidyne, Inc. and Space Dynamics Laboratory propose to develop an algorithm to improve the radiometric visualization of facetted vehicle models. The new algorithm will address the problem of optimizing the calculation of non-diffuse radiation reflected from curved surfaces. The algorithm will start with a coarsely faceted global model of a vehicle and Bidirectional Reflectance Distribution Functions describing the local character of the reflection. The algorithm will subdivide the facets as necessary to reduce the errors in the radiance specularly reflected from curved surfaces. While it is not possible to reduce both run time, i.e., the number of facets, and errors simultaneously, the algorithm will produce an appropriately facetted description for a given prescribed error. In Phase I the Visidyne Team will develop and test the facet subdivision algorithm for an ellipsoid as surrogate for a complex vehicle. The ellipsoid illustrates the range of reflection geometries and provides a spectrum of surface curvatures while being described with simple, analytical, geometric equations. The primary benefit of Phase I will be the development and validation of a new algorithm for the optimal subdivision of a facetted description of curved surfaces. The new algorithm will improve the quantitative rendering of complex objects viewed by reflected light. It will help military analysts assess the visibility of new vehicles based on their designs. By improving visual realism in the modeling/rendering process the new algorithm will be of value in commercial visualization products for both Computer Aided Design and Simulation.
