It is not uncommon to have to create a duct fitting that not only transitions from one rectangular size to another but also is offset. I assume this software will not create such a fitting. The simplest way I can see doing this (my suggestion) is for the user to create the 2 sections of ductwork at there respective X,Y and Z location,leaving out the transition/offset and then selecting a NEW command that prompts the user to select each duct and "WOLLA" a Transition/Offset fitting is created between the two ducts. A must need in the real world!
Thank you,
Aaron
P.S.
Jason, you are awsome...quick responses and very helpfull..A++++
AAG
Advance Design