A digital rendering method employs measured BRDF values for a modeled
material by collecting BRDF measurements using a precision reflectometer.
A laser light may be used as the source of the incident beam. Sparsely
measured BRDF data is resampled to build a data table of BRDF values over
a dense regular grid. The data table may be supplied as input to a
ray-tracing shader, and the shader may calculate BRDF values for modeled
light rays by interpolating between adjacent grid points for the data
table.