ALTA
alpha

ALTA can open common BRDF data formats such as:
We also provide our textbased data format (cf. format) that is compatible with Gnuplot.
ALTA can perform rational interpolation in the sense of Pacanowski et al. [2012]. Multiple implementations are provided with various library for the quadratic solver:
We also provide plugin to perform leastsquare interpolation of rational functions. These plugins are based on Eigen's solvers. Due to the illposed formulation of the leastsquare method, the solution provided by those plugins might have singularities (denominator equals to zero) in the definition domain.
ALTA can perform nonlinear optimisation to fit parametric BRDF models to data. It supports a wide variety of nonlinear optimizers such as:
We try to provide as much parametric BRDF models as possible. You will find the list of currently supported BRDF models in the Function plugins list page.
Writing command lines can be burdensome. To avoid having to write lengthy command lines, we provide a scripting mechanism to launch ALTA commands from XML formatted files or Python bindings.