SpaceClaim software supports, amongst other formats, export to DWG format so it is your best and perhaps also only way to convert its own .scdoc CAD files. We have found no 3rd party software that would support SpaceClaim formats.
Convert SpaceClaim 3D CAD document to AutoCAD drawing.
We found one software available in the database for this conversion.
Microsoft Windows software - convert scdoc to dwg on Windows
A 3D solid modeler for engineers
Convert from scdoc 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.