The only way to reliably produce .cdx files (compressed CorelDRAW compressed drawings) is to use CorelDRAW as no 3rd party software is known to us that could be able to create .cdx files from other sources, including .cdr images that also come from CorelDRAW.
Convert CorelDRAW vector or bitmap graphics to CorelDRAW compressed drawing.
We have found one software suitable in our database for this conversion.
Microsoft Windows software - convert cdr to cdx on Windows
A set of applications used by professional graphic designers
Convert from cdr file format
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.