A catdrawing to dwg conversion represents export of CATIA CAD drawings to AutoCAD DWG format, something that can be easily achieved using CATIA.
If you do not have access to CATIA, you have to look for alternative 3D modeling / CAD software with CATIA format support or some dedicated CAD-converter solution.
Open CATDRAWING file Open DWG fileA 3D CAD translation software