Echoing copy from an AUGI post.
The Revit MEP User Assistance team (the group responsible for help and tutorials) has been working on documenting some of the calculation methods that are used in Revit MEP. We are posting some of the information in a “pre-release” state to try and get feedback on how we can better meet your needs.
The first of these reviews is on how duct sizing in Revit MEP works, with additional sections to follow as we get them completed. Any and all comments are welcomed about the information we provide in the attached files.
If the contents of these documents don’t apply to you, please don’t feel like you need to review them (i.e. if you're the electrical person, don’t review duct sizing stuff), but if you know someone who might be interested please let them know. The more feedback we get the better we can make the documentation.
Vist the Inside the System blog
Thanks for your help!
Karen Smith (Autodesk)