round duct fitting for split

[AnmarieJames8335]

ok, HVAC guys, I need your help on this.  Take a look at this picture of a mech/elec room ceiling. I can manage the flex and rigid duct, and I've got the fan. But how the heck do I recreate this duct split fitting?

I looked online for something existing that's even similar, but haven't come up with any splits for round duct. So now I'm trying to create one, which is proving harder than anticipated. The ducts are 8" diameter and 4" diameter, which Revit can blend, but it looks really weird, and not at all like the picture.  And it seems that to create a blend, the top and bottom profiles must be parallel, which doesn't quite work for this, as one of the 4" ducts goes off at an angle to the 8" duct. The closest I've gotten is to create an excentric blend and then mirror it to create the second, creating an overlap. They won't join, so it's not really a useable solution.

I'm open to any ideas.

AJ

[julianjameson8403]

How about taking a wye fitting from the plastic plumbing families and chnaging the categories and connector types to try and get it to look how you are anticipating. Before using it, test it in a dummy project first in case the change between categories affects the family in an adverse way.

[AnmarieJames8335]

Interesting concept, and I think it has the potential to work.  I copied a pvc wye family and changed it to a duct fitting family. Then I swapped the pipe connections for duct connections and tried it out. The connections work, but the wye isn't adjusting to the chosen size of duct like the original pipe wye does. I'm thinking this is because the original family uses a Lookup Table.

I found the table and was planning to copy and rename it to match the new duct fitting family name, but I'm not sure where to put it. The only folders within the Lookup Tables folder are Pipe and Conduit. Can a duct fitting family even use a lookup table? Seems like I read somewhere that only certain family types can use them.

For this, I really just need the one size, so maybe I'll create a type that's the correct size in the original famly, then saveas and convert to a duct fitting family.

AJ

[vewright]

Revit MEP has an assortment of wye fittings for round duct. They don't look exactly like the photo, but should suffice.