  Recently, a Monte Carlo method has been presented which allows for the
form-free retrieval of size distributions from isotropic scattering patterns,
complete with uncertainty estimates linked to the data quality. Here, we
present an adaptation to this method allowing for the fitting of anisotropic 2D
scattering patterns. The model consists of a finite number of non-interacting
ellipsoids of revolution (but would work equally well for cylinders),
polydisperse in both dimensions, and takes into account disorientation in the
plane parallel to the detector plane. The method application results in three
form-free distributions, two for the ellipsoid dimensions, and one for the
orientation distribution. It is furthermore shown that a morphological
restriction is needed to obtain a unique solution.
