Update 3 is now available for Revit 2013 products.
For Autodesk Revit Architecture, Autodesk Revit Structure, and Autodesk Revit MEP, you can find the update in the Data & Downloads > Updates section of each product page.
The update for Autodesk Revit 2013 can be found in the Design & Creation Suites Support > Data & Downloads > Updates & Service Packs section.
Here are the direct links:
Revit Architecture 2013 Update Release 3
Revit Structure 2013 Update Release 3
Revit MEP 2013 Update Release 3
Installation ReadMe files and Update Enhancement PDFs are available at each of these locations as well.
If you are using ProjectWise and Revit there appears to be an issue with the file format on Update Release 3 files. If a file is saved on PWise by a UR3 machiine you will not be able to open it again. I have sent Bentley a service ticket this morning.
Posted by: TheBIMinator | June 18, 2013 at 09:02 PM