Perhaps you have signed up at an Autodesk online community like the Autodesk discussion forums or the Autodesk Feedback Community where Autodesk Beta and Labs projects happen and you didn’t think much about the username set as yoyoyoasdfasdf.
Now you want to change your username that is displayed in the forums to something more appropriate, but how? Its actually quite easy but not obvious.
Go to http://accounts.autodesk.com then select Security Settings and change your Username there.