Several ellipsometric and spectrophotometric data files can be fitted simultaneously. Incoherent reflections (single or multiple) in the internal faces of the substrates can be taken into account.

Data files from different samples obtained from the same coating run can be fitted simultaneously.

The errors in the measurement (imprecision of spectral data) are always taken into account in the fitting algorithms.

Many models have been included for describing the spectral behavior of complex refractive index (for transparent materials, semiconductors, metals...), covering a wide range of applications.

Effective Medium Approximation (EMA) models for the description of layers with mixtures of materials are also available. The optical constants of the materials are read from a file.

For coatings with many layers, the characteristics of the component materials can be linked between the layers, in order to reduce the number of parameters and to obtain more meaningful results.

The fittings can be restricted to regions of the spectra, named "targets". This allows to exclude inaccurate data that could prevent a meaningful characterization.

The fitting procedure can also include an estimation of the error on the parameters, thus providing an assessment on the quality of the result. This estimation is done by evaluating the covariance matrix of the χ² at its minimum.