It is simple to create a material from a data file that contains real and/or imaginary refractive index data. First, open the RSoft CAD and go to the Material Editor. Then, click New Material in the top toolbar to create a new Project Material, click the Import NK Data button highlighted in Fig 1a, and then select the material data file. To illustrate the procedure, we use Molybdenum (Mo) data from the CRC Handbook of Chemistry and Physics. The refractive index data must be in the RSoft file format: three columns of data for wavelength (μm), real and imaginary parts of the refractive index. For more information about this format, please refer to the October 2013 RSoft Enews. If needed, click Display to show the contents of the data file as in Fig.1b.