We can produce ductwork design drawings, where both the size and thickness of the duct is showing  and on the other hand types of connection, construction of straight  segments, etc.
The specification  for the preparation of the above drawings are drawn from the literature (SMAGNA) and the benefits from this study are:
Reducing the weight of the ducting (up to 35%)
Scientific and no empirical instructions for connection and construction of the ductwork
And this is a service we only can offer.