CATDRAWING and CATPART file types are both created in CATIA CAD software from Dassault Systemes. However, it doesn't look like these two formats can be converted between each other, because they serve different purpose and contain different CAD data.
Convert CATIA drawing file to CATIA part data.
We found 2 software records in the database related to .catdrawing to .catpart file format conversion.
Microsoft Windows software - convert catdrawing to catpart on Windows
A PLM/CAD/CAM/CAE software suite
Convert from catdrawing file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned catdrawing to catpart. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
A CAD converter with huge format support