PowDll converter and Convx are the two common software used for XRD data conversion from one format to another. Your problem here is to convert one .raw data to another .raw (for Diffrac.Eva), and unfortunately neither software can do the job based on my experience (I haven't tried the newest versions though). Can you save the Rigaku .raw data as .txt or some other format (e.g. CPI) that can be opened with for example windows notepad? All you need is X, Y data (i.e. 2 theta and Intensity). Once you have that and know the X-ray wavelength (and whether it contains K alpha2 or not) , you can then use the two software to convert the data (e.g. TXT) into the .RAW format that can be loaded into the Eva software. If you use Convx to convert TXT into RAW (Eva), select 'ASCII' as the type for the input file and 'DIffracPlus Raw' as the output. Good luck!