I'm trying to get a hang of how to automatically generate duct layouts in Revit MEP 2010. I have attached a simple project (which just consists of 2 diffusers, a VAV box, and an AHU) on which I'm trying to figure it out. I can create a supply system by selecting either of the diffusers or the VAV box, create supply system button, edit system, add equipment, and select the VAV. Then when I go to generate the duct layout it lays it all out for me in 3D. Sweet! One problem though: it connects the diffusers to the inlet of the VAV. That's question #1.
Question #2: If I try to add the AHU to the system, it give the error "Cannot add 05 to System. There is no available connector matching the System Type (Supply Air) for the System.", and in fact, if I attempt to create a system with the AHU, supply air is not an option, although editing the (OOTB) family reveals that there is in fact a supply air connector on the unit. Any idea why this is?