FBX Export would fail if one of the names (avatar, cloth, acc.) has a white space at the end
I have spent a few hours trying to figure out why I cannot export one of my characters to FBX in CC3, while I had no problem exporting it in CC2. Finally I have found a cloth name which had a white space at the end.
1. Within the default project add a white space at the end of any name.
Like rename "Bra" to "Bra "
2. Try to export to FBX
Suggestion: Evaluate names and Trim white spaces. Users might accidentally add some and then would have a headache trying to figure out the problem with export.