I have an assembly that was saved as a part, so the part has 81 bodies in it. Now I want to combine it all into one body. If I select all of the bodies and do the Combine/Add command, then it errors and says "Unable to create a single body that is the sum of the input body". So my conclusion is that at least one of those 81 bodies must be floating and not touching the other parts. Is there a way to just combine anything that is touching anything else to just reduce the number of bodies to the fewest possible?

The only way I can think of doing it now is to go through and do 81 combines of 2 parts at a time until one of them doesn't work. Or I could pick random groups of 10 bodies and see it they'll combine, if not pick another random set of bodies and try again. Either way I might miss two parts that could possibly both combine to a third part but not independently to each other.