Can I convert .nwd files directly to .dwg format.
Converting Autodesk Navisworks Documents directly to AutoCAD Drawings (.nwd to .dwg conversion) is not possible. Navisworks documents (.nwd) are somewhat different to .nwf files (Navisworks File Sets), since they contain all source data. Thus the documents can be viewed as standalone projects. Naviswork file sets merely store references to those source data files. They act as snapshots of current projects' file sets.
We are not aware of any available software or conversion utility capable of converting .nwd to .dwg format.
You can, however, try to export your project to .nwf format. Converting .nwf to .dwg is then quite straightforward.