Autodesk has now introduced your Account in place of the previous Subscription Center.
Details are outlined in Autodesk Account FAQ Customers. Please read it carefully.
In summary, to download software, extensions, request boxed copies, … proceed as follows:
1. www.autodesk.com/account
2. Sign in with:
Autodesk ID or email address
Password (use “Forgot your password?” if not known)
3. All your products are displayed
4. Click on product required for serial numbers, product keys and options
5. On right of selected product choose from options:
Download now OR
More actions (see example Autodesk products options for details)

Autodesk Account Sample